Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 7-Day Trial for You or Your Team.

Learn More →

Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and its application as a novel mesoporous sorbent for preconcentration and trace detection of copper and cadmium ions

Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and its... RSC Advances PAPER Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and Cite this: RSC Adv.,2015, 5, 68500 its application as a novel mesoporous sorbent for preconcentration and trace detection of copper and cadmium ions† a a a b Mohammad Behbahani, Azam Aliakbari, Mostafa M. Amini, Ahmad S. Behbahani and Fariborz Omidi We are introducing diphenylcarbazide functionalized siliceous mesocellular foam as a novel mesoporous solid-phase for the extraction of heavy metal ions including copper(II) and cadmium(II). The synthesized mesoporous sorbent was characterized using Fourier transform infrared spectrometry, scanning electron microscopy, elemental analysis, nitrogen adsorption–desorption isotherms and thermal analysis. Determination of the extracted ions was performed by flame atomic absorption spectrophotometry. Effects of pH value, adsorption and desorption time, type, concentration and volume of the eluent, breakthrough volume, and effect of potentially interfering ions were studied. Under optimized conditions, the extraction efficiency is >98%, and the limits of detection are 0.1, and 0.04 mgL for the ions of copper and cadmium, respectively, and the adsorption capacities for these ions are 160 and Received 30th May 2015 190 mg g . The obtained data for adsorption capacity of the sorbent shows the high tendency of the Accepted 3rd August 2015 sorbent toward the mentioned target ions. Finally, this sorbent can be used as a simple, rapid, reliable, DOI: 10.1039/c5ra10240e selective and sensitive method for the determination of trace levels of copper(II) and cadmium(II)in www.rsc.org/advances different water samples. 10–16 trace amounts of heavy metal ions in various matrices. 1. Introduction However, the direct determination of trace amounts of these ions in real samples using these techniques is challenging due Heavy metals such as cadmium and copper ions are common to matrix effects and the need for extremely low detection limits. pollutants of water, food, soil and biological samples and have Hence, sample pre-treatment, such as preconcentration of the generated intense research interest due to their toxicity to 17,18 1–4 analyzed elements and matrix separation, is oen necessary. humans, animals, and other living creatures. Hence, the A number of separation and preconcentration procedures, development of fast, reliable and effective analytical methods 19,20 21 such as solid phase extraction (SPE), coprecipitation, cloud for the determination of trace amounts of cadmium and copper 22 23 5–9 in real samples is an important area of research. point extraction (CPE) and liquid–liquid extraction (LLE), have been developed and used for the enrichment and separa- Several analytical techniques, including ame atomic tion of heavy metals at trace levels in various environmental absorption spectrometry (FAAS), electrothermal atomic samples. Among these, solid phase extraction is widely accepted absorption spectrometry (ETAAS), inductively coupled plasma as an ideal, and a powerful technique because of its simplicity, optical emission spectrometry (ICP-OES) and inductively high enrichment factor, low cost, low or no consumption of coupled plasma-mass spectrometry (ICP-MS) and electroana- organic solvents, ease of automation and ability to be coupled lytical instruments are widely used for the determination of with various modern detection techniques. Siliceous mesostructured cellular foams (MCF) is a novel mesoporous silica material template by oil-in-water micro- Department of Chemistry, Shahid Beheshti University, Evin, Tehran, Iran. E-mail: [email protected]; Fax: +98 21 22431683; Tel: +98 21 22431661 emulsions with high surface areas and well dened pore Department of Chemistry, Applied Chemistry, Shahid Beheshti University, Evin, structures have attracted considerable attention for applica- Tehran, Iran tions in catalysis, adsorption and separations. Compared to Department of Occupational Health Engineering, School of Public Health, Shahroud MCM-41 and SBA-15, MCFs prepared with the microemulsion University of Medical Sciences, Shahroud, Iran templating process by using 1,3,5-trimethylbenzene (TMB) as † Electronic supplementary information (ESI) available. See DOI: the organic swelling agent has a well-dened ultra large pores 10.1039/c5ra10240e 68500 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances (24–42 nm), a narrow pore size distribution, and three dimen- were recorded (KBr pellets) on an 8700 Shimadzu Fourier sional (3-D) pore structures. Furthermore, MCFs with uniform transform infrared (FT-IR) spectrophotometer. spherical pores interconnected by windows of around 9–22 nm 2 1 have high BET surface areas (up to 1000 m g ). Their 3-D pores 2.3. Synthesis of spherical siliceous mesocellular foam are substantially larger than those of the ordered counterparts Spherical MCF sample was synthesized by modifying the SBA-15 and MCM-41. MCFs can provide more favorable condi- conventional MCF synthesis method. In a typical preparation, tions for mass diffusion. 4.0 g of triblock copolymer Pluronic P123 were dissolved in an In this work, we have prepared organic–inorganic based acidic solution (10 mL of HCl (37%) and 65 mL of H O). A total conjugate material as an adsorbent for efficient extraction and of 4.0 g of 1,3,5-trimethylbenzene (TMB) were then added, and preconcentration of cadmium and copper ions from water the resulting solution was heated to 37–40 C with vigorous solutions. For preparation of the new class conjugate adsorbent, stirring for 2 h to synthesize the microemulsion (template). A a specic functional group of organic ligand (diphenylcarba- total of 9.2 mL of tetraethoxysilane (TEOS) was then added and zide) was successfully incorporated into siliceous mesocellular stirred for 5 min. The solution was transferred to an autoclave foam. The synthesized sorbent was characterized by Fourier and aged at 40 C for 20 h under a quiescent condition. A total of transform infrared spectroscopy, scanning electron microscopy, 46 mg of NH F was added, and the mixture was aged at 100 C elemental analysis, nitrogen adsorption–desorption isotherm for another 24 h. The resulting precipitate was ltered, washed and thermal and elemental analyses. The effects of pH, ow with water and ethanol, and dried. The white powder obtained rates, type, concentration and volume of eluent for simulta- was calcined in air at 550 C for 6 h. neous elution of copper and cadmium ions, break through volume and effect of coexisting ions on the separation and 2.4. Preparation of diphenylcarbazide functionalized MCF determination of these heavy metals were investigated. The developed method was applied for determination of copper and In this approach, in a typical reaction, 1.0 g of MCF was sus- cadmium ions in several real samples, and the accuracy of the pended in 80 mL dried toluene, and 3-chloro- method was conrmed by standard reference material. propyltriethoxysilane (4.0 mL) was added to mixture and was reuxed for 48 h under nitrogen atmosphere. The resulted white solid was suspended in 100 mL of toluene and triethyl- 2. Experimental amine mixture (3 : 1 v/v) and an excess amount of 1,5-diphe- 2.1. Chemicals nylcarbazide (1.0 g) solved in the minimum amount of acetone and then added to the reaction mixture. Aer 24 h reux the Triblock copolymer poly(ethylene oxide)-b-poly(propylene resulted solid was removed from solvent by ltration, washed oxide)-b-poly(ethylene oxide), Pluronic P123 (MW ¼ 5800), was with methanol and acetone and then dried at room tempera- purchased from Aldrich Chemical Inc. Tetraethyl orthosilicate ture. FT-IR spectroscopy, SEM, elemental and thermal analysis, (TEOS), ammonium uoride, 1,3,5-trimethylbenzene (TMB), and BET surface area measurement conrmed the synthesis of hydrogen chloride (HCl), (3-chloropropyl)triethoxysilane, MCF-diphenylcarbazide. 1,5-diphenylcarbazide, triethylamin (TEA) were purchased from Aldrich Chemical Inc. Toluene and acetone ware obtained from 2.5. Real sample pretreatment Mujallali Company (Tehran, Iran). All chemicals were used as received without any further purication. The tested water samples were tap water (Tehran, Iran), sea water (Persian Gulf and Caspian Sea) and lake water. The water samples were collected in polyethylene bottles. They were 2.2. Instrumentation cleaned with acid bath, and then ltered through nylon lters Copper and cadmium concentration was determined by an (Millipore, 0.22 mm) before the analysis. Certied reference AA-680 Shimadzu (Kyoto, Japan) ame atomic absorption material (0.1 g) were digested using 8 mL mixture of 5% aqua spectrometer (FAAS) in an air–acetylene ame, according to the regia with the assistance of a microwave digestion system. user's manual provided by the manufacturer. Copper and Digestion was carried out for 2 min at 250 W, 2 min at 0 W, cadmium hollow cathode lamps (HCL) were used as the radia- 6 min at 250 W, 5 min at 400 W, and 8 min at 550 W, and the tion source with wavelengths of 324.8 and 228.8 nm, respec- mixture was then vented for 8 min. The residue from the tively. The pH was measured at 25  1 C with a digital Metrohm digestion, as well as a controlled digestion was then diluted 827 Ion Analyzer (Herisau, Switzerland) equipped with a with deionized water. Finally, the pH of each solution was combined glass–calomel electrode. Scanning electron micros- adjusted to 7.0 by drop wise addition of HCl and NaOH for copy (SEM) was performed with a JEOL JSM-7400F electron separation and preconcentration of cadmium and copper ions microscope. The nitrogen adsorption–desorption isotherms from the water samples. were obtained using a BELSORP-mini system; the sample was degassed at 150 C for 10 h before analysis. Thermal analysis 2.6. Solid phase extraction procedure (TGA-DTA) was carried out on a Bahr STA-503 instrument in air at a heating rate of 10 C min up to 800 C. The nitrogen and Batch experiments were used for adsorption and desorption sulfur contents in the modied MCF were obtained with a studies. The dried synthesized sorbent (10 mg) was immersed in Thermo Finnigan Flash-1112EA microanalyzer. Infrared spectra a solution containing 2 mg L concentration of copper and This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68501 RSC Advances Paper cadmium ion. The pH of solution was adjusted to 7.0. Aer spherical cells. A schematic synthesis of the sorbent applied in stirring for 5 min, the solution was centrifuged and ultrapure this study is represented in Fig. 1 which contains three parts; water was used for washing of adsorbed copper and cadmium MCF synthesis, functionalization MCF with (3-chloropropyl) ions. The solid mesoporous sorbent was suspended in 2 mL of triethoxysilane (MCF-Cl) and reaction of diphenylcarbazide HCl (1 mol L ) as the eluent and stirred for 2 min. The resulted with MCF-Cl to produce (MCF-DPC). MCF synthesis in rst part solution was subsequently centrifuged and separated, and the of scheme has several stages containing emulsion formation, concentration of copper and cadmium ions was measured by the silica source putting on the template and its hydrolysis FAAS. under acidic condition and the elimination of the organic part with calcination. The pore size, window size, total pore volume and surface area of the spherical MCF sample prepared were 3. Results and discussion shown in Table 1 which characterized by N adsorption– 3.1. Characterization of the synthesized sorbent desorption isotherm. Furthermore FT-IR analysis of MCF showed a FTIR spectrum typical of silica (Fig. 2a). Spectrum MCF has a unique three-dimensional pore structure, whose presents the typical Si–O–Si bands of the inorganic framework: ultra large cell-like pores (20–50 nm) are interconnected by symmetric vibration mode around 800 cm and asymmetric 27,29,30 windows of a smaller opening (9–26 nm). The pore size stretching vibration around 1080–1100 cm . The absorption and window size of MCF could be easily controlled by using peak at 960 cm is attributed to the bending vibration of the organic swelling agent (TMB) and inorganic mineralizing agent Si–OH bands and the bands at around 1700 and 3400 cm can (NH F). However, conventional MCF consists of large, irregular be assigned to the water stretching modes and bending vibra- particles of tens of micrometers, the preparation procedure tion modes of the free or absorbed water, respectively. To applied in this article results in spherical MCF particles functionalize MCF with diphenylcarbazide, hydroxy groups on compared to the original recipe for MCF synthesis. This strategy the synthesized MCF surface was rstly reacted with silanol in the synthesis leads to synthesize MCF with spherical groups of (3-chloropropyl) triethoxysilane as a linker which is a morphology compared to conventional MCF with long straight well-established method to prepare the functionalized silica. It cylinders morphology. Actually emulsion made from oil-to- must be mentioned that there are hydroxyl groups in pore and polymer (TMB/P123) ratios above 0.2, would nally make Fig. 1 Schematic diagram of the synthesized MCF-DPC sorbent. 68502 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances Table 1 The textural properties of MCF-DPC sorbent a a 3 1 2 1 Pore size (nm) Window size (nm) Pore volume (cm g ) Surface area (m g ) Ref. MCF 29.4 17 2.1 557.3 34 MCF-DPC 25 16 1.95 480 This work The pore size and window size were derived from the adsorption branch and desorption branch of the N sorption isotherm, respectively, according to a simplied Broekhoff-de Boer method (BdB-FHH). also window parts, so the functionalization is occurred in both. Brunauer, Emmett and Teller (BET) method. Meanwhile, total 3 1 Modication with (3-chloropropyl) triethoxysilane, which is pore volume (V ,cm g ) was calculated as the amount of pore performed by condensation of –OH on MCF and ethoxy groups nitrogen adsorbed at P/P ¼ 0.990. The summary of the textural of linker, is presented in the second part of scheme (only the two properties of the prepared sorbent are shown in Table 1, which groups of linker in the pore site as an example is shown). Aer are decreased in comparing with MCF from 29.4, 17, 2.1 and modication, new bands in FT-IR spectrum at 2850–3000 cm 557.3 to 25, 16, 1.95 and 480 in pore size (nm), window size 3 1 2 1 were observed, which associated with C–H vibration (Fig. 2b). (nm), pore volume (cm g ) and surface area (m g ) respec- Last part of the scheme contains reaction of MCF-Cl with tively, indicating that incorporation of diphenylcarbazide 1,5-diphenylcarbazide by the remove of HCl, which is trapped by ligand into MCF silica supports with (3-chloropropyl) triethoxy- TEA in order to increase the reaction yield. The presence of silane as a linker. The decline in both pore and window sizes in bands at 1250–1550 cm conrmed 1,5-diphenylcarbazide MCF-DPC than MCF conrms the functionalization in both groups' immobilization on MCF-Cl (Fig. 2c). parts. As shown in Fig. 4, a typical type IV adsorption isotherm The electron microscopy studies were conducted to gain with a H hysteresis loop is obtained for MCF-DPC indicating insight in the morphology of MCF-DPC. Fig. 3 shows its image typical mesoporous materials with large pore size and narrow that clearly conrmed a spherical particle of MCF-DPC with a pore size distributions. size of about 5 mm in diameter along with some agglomeration In order to determine the loading of 1,5-diphenylcarbazide, of these particles. Furthermore, SEM indicates that the MCF the N content in this sample was measured by elemental structure aer two stages of modication hasn't changed. analyzer (CHN). The results showed 1.93% N content which is The textural properties of MCF-DPC sorbent were derived corresponds to 0.4 mmol g 1,5-diphenylcarbazide loaded on based on nitrogen adsorption–desorption data using Barrett, the MCF mesoporous. Joyner and Halenda (BJH) method to obtain the average pore The thermal stability of MCF-DPC was studied by carrying size and window size. Specic surface area was evaluated using out TGA-DTA analysis (Fig. 5). A weight loss occurred between Fig. 2 FT-IR spectra of (a) pure MCF, (b) MCF-Cl and (c) MCF-DPC. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68503 RSC Advances Paper Fig. 6 indicate that the target ions could be retained simulta- neously on functionalized MCF in the pH of 7.0. The adsorption of cadmium and copper ions by the sorbent increased from pH 2.0 to 7.0 but decreased slightly from pH 8.0 to 10.0. In the low pH, the mesoporous adsorbent was positively charged (the –N group of ligand in low pH is in the form of –NH ) and an elec- trostatic repulsion occurred between the positively charged ana- lytes and the adsorbent particles. Meanwhile, the observed decrease in retention percentage of cadmium and copper ions on the sorbent at the pH values higher than 7.0, is most probably due to the precipitation of target ions in the hydroxide form, which leads to decreasing the concentration of free cadmium and copper ions in sample. Also, in the presence of modied MCF by DPC in the extraction solution, other parameters can inuence in the retention of target ions in different pH (such as different K of complexation of ligand with target ions and viscosity of the Fig. 3 Scanning electron micrograph of MCF-DPC. solution in different pHs). Thus, pH of 7.0 was chosen as the optimum pH for further experiments. 250 C and 800 C which is accompanied with exothermic peak 3.3. Effect of the adsorbent amounts at 500 C in the DTA curve, corresponds to the oxidative decomposition of the organic part associated with 1,5-diphe- Compared to conventional sorbents, MCFs offer a signicantly nylcarbazide. Furthermore, according to thermal analysis, the higher surface area-to-volume ratio and a short diffusion route, prepared composite is stable up to 200 C. According to the 11% which results in high extraction capacity, rapid extraction weight loss in the TGA curve, the amount of ligand introduced dynamics and high extraction efficiencies. Therefore, satisfac- into MCF-DPC is 0.39 mmol g which is in good agreement tory results can be obtained with fewer amounts of these with the loading result of elemental analysis. adsorbents. For the optimization of the amount of adsorbent, 5, Overall, characterization demonstrated that the obtained 10, 15 and 20 mg of the modied MCF were tested. In the functionalized MCF possesses excellent connectivity, large present work, by increasing amounts of the modied MCF due cavities, and small and-well tailored windows, which might be to increase in the surface area and accessible sites to the eminently suitable for post application like adsorption. adsorption of the analytes, the extraction efficiency increased. Quantitative extraction of the target ions was achieved using only 10 mg of the modied MCF. At higher amounts of the 3.2. The effect of pH on retention of target ions by the adsorbent, the extraction efficiency was almost constant. synthesized mesoporous sorbent Therefore, 10 mg of the sorbent was chosen for further studies. To study the effect of pH on the extraction of target ions, the pH of 25 mL of different sample solutions containing 2 mg L of 3.4. Equilibrium sorption time each target ions was adjusted in the range of 2–10. Interaction In order to investigate the effect of shaking time on the between electron pair of –N of ligand on mesoporous sorbent and extraction efficiency, extraction experiments were carried out at target ions were affective at natural pHs. The obtained results in Fig. 4 Nitrogen sorption isotherm and corresponding pore size and window size distributions of MCF-DPC. Fig. 5 TGA-DTA analysis of MCF-DPC. 68504 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances simultaneous desorption of the target ions by 2.0 mL of the 1 mol L HCl. 3.6. Effect of sample volume Due to the low concentrations of trace metals in real samples, by using samples with large volumes, the trace metals in these volumes should be taken into smaller volumes for high pre- concentration factor. Hence, the maximum sample volume was optimized by the investigation of the recovery of target ions in various synthetic samples, volumes in the range of 25–600 mL containing 0.01 mg of targets were used to study. In the opti- mization of the sample volume, 10 mg of the sorbent was used. The recovery of targets from different volumes of aqueous solutions were shown in Fig. 7. The recovery was found to be stable until 300 mL and was chosen as the largest sample volume to this work. 3.7. Effect of potentially interfering ions Because of the presence of other elements in real samples, the determination and preconcentration of target ions is difficult. So, the effects of common coexisting cations and anions on the adsorption of the target ions on the modied MCF were inves- tigated. In these experiments, 150 mL of solution containing 0.003 mg target ions were added to interfering cations and anions and treated according to the recommended procedure. The results in Table 3 show that the vast majority of transition, alkaline, and earth alkaline metals do not interfere at environ- mentally relevant concentrations. This is due to the low capacity or rates of adsorption for interfering ions under optimum condition. Thus, these results conrm that the procedure using modied MCF is independent of matrix interferences. Fig. 6 (a) The effect of solution's pH on the retention of target ions by the mesoporous sorbent. (b) The results for the samples with only copper and cadmium ions (without adsorbent) at different pHs as a 3.8. Maximum adsorption capacity control (2 mg L of target ions was analysis without adsorbent in In order to determine how much sorbent was required to different pHs and the obtained concentration was presented). quantitatively remove a specic amount of a metal ion from the solution, the capacity of the sorbent was calculated. To evaluate this factor, 25 mL of a solution containing 2 mg target ions 2, 5, 10 and 20 min time intervals. According to the results, an underwent the extraction procedure, and the maximum equilibration time of about 5 min was required for quantitative capacity was calculated (with 10 mg of the synthesized sorbent). extraction of the target ions from solution into mesoporous The obtained capacities of modied MCF were found to be 190 solid phase. Thus, the mixtures have been shaken for 5 min to and 160 mg g for cadmium and copper ions, respectively. In reach equilibrium in the subsequent experiments. order to evaluate the maximum adsorption capacity, the difference between concentration of the solution before and the concentration of the solution aer solid phase extraction 3.5. Desorption condition procedure by the sorbent was calculated. A series of selected eluent solutions, including HNO , HCl, HNO : HCl and CH COOH were used for elution of target ions 3 3 1 3.9. Langmuir isotherm models from the modied MCF. The results show that 1 mol L HCl is a suitable and effective eluent to simultaneous elute the target In this work, Langmuir isotherms were used to measure the ions from modied MCF. The effect of eluent volume on the adsorption of copper and cadmium ions onto DPC-MCF recovery of target ions was also studied (Table 2). Also the surface. The Langmuir adsorption model is a theoretical results show, quantitative recovery could be obtained with equation and applicable to homogeneous binding sites and 2.0 mL of 1 mol L HCl. Therefore, 2.0 mL volume of eluent for assumes that the molecules are adsorbed at a xed number of desorption of target ions was used in the following experiments. well-dened sites, each of which can only hold one molecule. Desorption times were evaluated in the range of 2–10 min. These sites are also assumed to be energetically equivalent and The results showed that the time of 2 min is sufficient for distant to each other; therefore, there are no interactions This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68505 RSC Advances Paper Table 2 The effect of type, concentration, volume and time of the elution step on the extraction recovery of cadmium and copper ions a b R (%)  S Eluent Concentration (mol L ) Desorption time (min) Volume (mL) Cadmium Copper HNO 2 10 5.0 87.0  1.4 93.0  1.2 HCl 2 10 5.0 99.0  1.0 99.0  1.0 CH COOH 2 10 5.0 48.0  1.1 40.0  1.3 HNO : HCl 0.5 : 0.5 10 5.0 89.0  1.3 87.0  1.2 HCl 1.5 10 5.0 99.0  1.0 99.0  1.0 HCl 1 10 5.0 99.0  1.0 99.0  1.0 HCl 0.5 10 5.0 86.0  1.2 82.0  1.0 HCl 0.25 10 5.0 65.0  1.3 70.0  1.2 HCl 1 10 4.0 99.0  1.0 99.0  1.0 HCl 1 10 3.0 99.0  1.0 99.0  1.0 HCl 1 10 2.0 99.0  1.0 99.0  1.0 HCl 1 10 1.5 90.0  1.2 75.0  1.3 HCl 1 5 2.0 99.0  1.0 99.0  1.0 HCl 1 3 2.0 99.0  1.0 99.0  1.0 HCl 1 2 2.0 99.0  1.0 99.0  1.0 a b Recovery. Standard deviation. between molecules adsorbed on adjacent sites. The amount of adsorption capacity and energy of adsorption, respectively. The Cu(II) and Cd(II) bound by the modied mesoporous sorbent Langmuir equation can be linearized in a normal form for the was calculated according to the following formula: determination of Langmuir constants: ðC  CÞV 1 1 1 Q ¼ ¼ þ 1000W Q Q bQ C max max e where Q is the amount of adsorbed Cu(II) and Cd(II) (mg g ); C and C are the initial and nal concentrations of Cu(II) and Cd(II) Langmuir equations for copper and cadmium at pH 7 for 25 (mg L ), respectively; V is the volume of mixture (mL); and W is mL of sample volume and 10 mg of the sorbent are as follows: the amount of sorbent (g). The Langmuir adsorption isotherm is expressed by following Y ¼ 0.0078X + 0.0053 (R ¼ 0.98) equation. Langmuir equations for cadmium ions Q bC max e Q ¼ 1 þ bC e Table 3 The effect of potentially interfering ions on the extraction recovery of cadmium and copper by the synthesized mesoporous where Q is the amount of adsorbed Cu(II) and Cd(II) ions on the sorbent MCF-DPC at equilibrium (mg g ), C is the equilibrium a b concentration of Cu(II) and Cd(II) ions in solution (mg L ) and R (%)  S Tolerable concentration ratio Q and b are Langmuir constants related to the maximum max Foreign ion X/cadmium and copper ions Cadmium(II) Copper(II) K 10 000 99.0  2.0 99.0  2.0 Na 10 000 99.0  1.0 99.0  2.0 Ag 1000 97.0  1.0 96.0  1.0 Cs 1000 97.1  1.2 96.5  1.1 2+ Ca 1000 97.0  1.1 96.5  0.9 2+ Mg 1000 96.2  1.4 98.5  0.6 3+ Al 1000 97.5  1.1 97.2  1.1 2+ Fe 900 97.1  1.4 98.5  1.0 2+ Ni 600 96.5  1.5 97.1  0.9 2+ Mn 800 97.2  1.2 97.5  0.5 2+ Pb 600 97.4  0.8 98.2  1.4 3+ Cr 700 96.5  1.1 97.2  1.4 CO 1000 98.4  0.9 98.0  1.2 SO 1000 97.0  1.4 97.0  1.5 CrO 800 97.0  1.2 97.0  1.4 PO 800 98.0  1.1 97.0  1.2 Cl 3000 96.0  1.2 97.0  1.5 a b Fig. 7 The effect of sample volume on the recovery of target ions by Recovery. Standard deviation. the mesoporous sorbent. 68506 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances value is above to unity adsorption is a favorable physical process. Y ¼ 0.0082X + 0.0062 (R ¼ 0.99) 1/nF q ¼ K C can be linearized in the logarithmic form and the Langmuir equations for copper ions e F e Freundlich constants can be determined: log q ¼ log K +1/nF log C According to the relations above, adsorption capacities for e F e Cd(II) and Cu(II) were calculated to be 188.7 mg g and 161.2 mg g , respectively. The plot of log(q ) versus log(C ) was employed to generate e e Furthermore, the essential characteristic of the Langmuir the intercept value of K and the slope of 1/nF (Table 4). The isotherm can be expressed in terms of a dimensionless equi- correlation coefficients obtained from Freundlich model is librium parameter, the separation factor (RL), which used in the comparable to that obtained from Langmuir model linear form. following equation, RL ¼ 1/(1 + bC ). The value of parameter RL The values of Freundlich constant 1/nF is between 0 and 1.0 indicates the nature of the adsorption process which irrevers- which also indicated that adsorption of cadmium (0.86) and ible (RL ¼ 0), favorable (0 < RL < 1), linear (RL ¼ 1), or unfa- copper (0.7) ions under the studied condition are suitable. vorable (RL > 1). The value of RL for the present system comes A comparison of the two isotherms based on the linear out to be 0.018 and 0.02 for cadmium and copper, respectively, regression coefficient (R ) values showed that the sorption of communicating the favorable adsorption of the target ions onto target ions on DPC-MCF nearly similar results (R ) for both DPC-MCF. Langmuir and Freundlich isotherm models, under the concentration range studied. 3.10. Freundlich isotherm model The Freundlich isotherm model is the earliest known relation- 3.11. Analytical performance ship describing the sorption process. The model applies to Under the optimized conditions, calibration curves were adsorption on heterogeneous surfaces with interaction between sketched for the determination of cadmium and copper ions adsorbed molecules and the application of the Freundlich according to the optimum extraction procedure. Linearity was equation also suggests that sorption energy exponentially 1 1 maintained 0.5–200 mgL for copper and 0.1–30 mgL for decreases on completion of the sorptional centers of an adsor- cadmium in initial solution (150 mL of sample). The correlation bent. This isotherm is an empirical equation can be employed of determination (R ) was 0.99 for copper and 0.99 for cadmium to describe heterogeneous systems and is expressed as follow: ions. The limit of detection, which is dened as C ¼ 3S /m, LOD b 1/nF q ¼ K C where S is the standard deviation of eight replicate blank e F e b signals and m is the slope of the calibration curve aer pre- where K is the Freundlich constant (L g ) related to the bonding concentration, for a sample volume of 150 mL, was found to be 1 1 energy. K can be dened as the adsorption or distribution coef- 0.1 mgL for copper and 0.04 mgL for cadmium ions, cient and represents the quantity of ions adsorbed onto adsor- respectively. The relative standard deviations for eight separate bent for unit equilibrium concentration. 1/nF is the heterogeneity experiments for determination of 7.5 mg of cadmium and factor and nF is a measure of the deviation from linearity of copper ions in 150 mL of water was 2.5 and 3.1, respectively. adsorption. Its value indicates the degree of non-linearity between Regression equation, dynamic linear range (DLR), correlation of solution concentration and adsorption as follows: if the value of determination (R ), preconcentration factor (PF), limit of nF is equal to unity, the adsorption is linear; if the value is below detection (LOD) and relative standard deviation (RSD) for to unity, this implies that adsorption process is chemical; if the cadmium and copper were calculated under optimized condi- tions and summarized in Table 5. Since 150 mL of the solution was preconcentrated to 2.0 mL, Table 4 The obtained data from Freundlich isotherm model the approximately preconcentration factor of 75 was obtained. Ion Freundlich model R K nF 3.12. Real sample analysis Cadmium Y ¼ 0.86X + 1.92 0.97 83.2 1.16 Finally, this method was performed on real samples to check its Copper Y ¼ 0.71X + 1.77 0.98 58.9 1.4 accuracy. Since the amounts of cadmium and copper ions in Table 5 Regression equation, dynamic linear range (DLR), correlation of determination (R ), preconcentration factor (PF), limit of detection (LOD) and relative standard deviation (RSD) for copper and copper were calculated under optimized conditions 2 1 1 b b a 1 Analyte Regression equation r LOD (ng mL ) DLR (ng mL ) PF Recovery (%) RSD (%) MAC (mg g ) Copper ion Y ¼ 8.53X (mg L ) + 0.001 0.99 0.1 0.5–200 75 >98 3.1 160 Cadmium ion Y ¼ 51.75X (mg L ) + 0.0004 0.99 0.04 0.01–20 75 >98 2.5 190 a b 1 Maximum sorption capacity. Recovery and RSD is calculated for 50 mgL of copper and cadmium ions. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68507 RSC Advances Paper Table 6 Analysis of copper and cadmium ion in different food samples cadmium ions was determined at optimum conditions in standard reference material (Soil (NCS DC 73323)). As it can Added Founded RR RSD be seen in Table 1S (ESI†), good correlation was achieved 1 1 Sample Ion (mgL ) (mgL ) (%) (%) between estimated content by the present method and refer- Tap water Copper — 10.2 — 2.1 ence materials. Therefore, modied MCF with diphe- 5.0 15.2 100.0 2.8 nylcarbazide can be used as a reliable solid phase for 50.0 59.5 98.6 2.6 extraction and determination of copper and cadmium ions in Cadmium —— — — real samples. 5.0 5.1 102.0 2.9 50.0 49.8 99.6 2.9 Caspian sea water Copper — 19.8 — 2.6 4. Conclusions 5.0 24.7 98.0 3.1 50.0 69.9 100.2 2.8 S-MCF microparticles with a spherical morphology and a Cadmium — 7.1 — 2.8 narrow particle size distribution were prepared by a simple 5.0 12.0 98.0 3.1 modication of the conventional MCF synthesis. The pore 50.0 56.9 99.6 2.7 Persian Gulf water Copper — 18.3 — 1.9 sizes and surface areas of S-MCF particles could be adjusted 5.0 23.4 102.0 2.7 without affecting the particle morphology. The S-MCF parti- 50.0 68.1 99.6 2.4 cles were functionalized with diphenylcarbazide groups, and Cadmium — 6.6 — 2.5 applied as a new class mesoporous sorbent for simultaneous 5.0 11.7 102.0 2.9 separation and trace detection of copper and cadmium ions 50.0 56.5 99.8 2.2 Lake water Copper — 15.2 — 2.1 in environmental water samples. Their high surface areas 5.0 20.3 102.0 2.8 gave rise to very good retention ability, as illustrated in the 50.0 64.9 99.4 3.1 separation of cadmium and copper ions. The highly inter- Cadmium — 2.3 — 2.7 connected porous structure and ultra large pore size allowed 5.0 7.3 100.0 2.5 MCF to be used as a sorbent for rapid extraction of ions and 50.0 52.1 99.6 2.5 molecules. In this work, for the rst time, modied MCF with diphenylcarbazide was utilized as an adsorbent for the simultaneous separation of ultra-trace amounts of cadmium and copper ions. This method is simple, rapid and reliable real samples are too low, some amount of the target ions was and found as a selective and sensitive method for the deter- also spiked in these samples. To test the reliability of the mination of trace levels of cadmium and copper ions. The method for extraction and determination of the target ions in convenient data was found for adsorption capacity, detection the environmental water samples were applied. The results limit and pre-concentration factor in the determination of demonstrate that quantitative recoveries of the target ions for the target ions and conrmed that this method using modi- modied MCF with diphenylcarbazide are achievable. The ed MCF with diphenylcarbazide has a high potential for results are listed in Table 6. extraction of metal ions. As a result, the LOD, pre- The concentration of copper and cadmium ions obtained concentration factor and maximum adsorption capacity of by modied MCF was compared to the standard reference this method is better than some of the previously reported material. For this reason, the concentration of the copper and 35–39 pre-concentration methods (Table 7). Table 7 Comparison of the proposed method with previously published work related to the extraction and determination of cadmium and copper ions 1 a b Instrument Method Elements LOD (ng mL)PF MAC Ref. ICP-OES AEDHB-SG sorbent Cadmium 0.012 100 0.40 mmol g 35 Copper 0.098 100 0.56 mmol g FAAS UA-IL-DLLME Cadmium —— — 36 Copper 0.17 100 — ICP-OES Morin-magnetic nanoparticle Cadmium —— — 37 Copper 0.9 28 — FAAS Chelating resin Cadmium 4.2 100 — 38 Copper —— — FAAS Modied silica gel Cadmium 1.1 27 0.067 mmol g 39 Copper 1.0 27 0.30 mmol g FAAS Diphenylcarbazide-MCF Cadmium 0.04 75 190 mg g This work Copper 0.1 75 160 mg g a b Preconcentration factor. Maximum adsorption capacity. 68508 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances 18 M. H. Karbasi, B. Jahanparast, M. Shamsipur and J. Hassan, References J. Hazard. Mater., 2009, 170, 151–155. 19 Z. A. Alothman, E. Yilmaz, M. Habila and M. Soylak, 1 G. Somer, A. N. Unlu, S. Kalayci and F. Sahin, Turk. J. Chem., 2006, 30, 419–427. Ecotoxicol. Environ. Saf., 2015, 112,74–79. 2 A. Bagheri, M. Taghizadeh, M. Behbahani, 20 H. R. Fouladian and M. Behbahani, Food Analytical Methods, A. A. Asgharinezhad, M. Salarian, A. Dehghani, 2015, 8, 982–993. H. Ebrahimzadeh and M. M. Amini, Talanta, 2012, 99, 132– 21 B. Feist and B. Mikula, Food Chem., 2014, 147, 225–229. 139. 22 S. Aslam Arain, T. G. Kazi, H. I. Afridi, A. R. Abbasi, 3 A. Bagheri, M. Behbahani, M. M. Amini, O. Sadeghi, A. H. Panhwar, Naeemullah, B. Shanker and M. B. Arain, M. Taghizade, L. Baghayi and M. Salarian, Talanta, 2012, Spectrochim. Acta, Part A, 2014, 133, 651–656. 89, 455–461. 23 G. Helle, C. Mariet and G. Cote, Talanta, 2015, 139, 123–131. 4 N. Jalbani and M. Soylak, Talanta, 2015, 131, 361–365. 24 C. F. Poole, A. D. Gunatilleka and R. Sethuraman, J. 5 M. Behbahani, Y. Bide, M. Salarian, M. Niknezhad, Chromatogr. A, 2000, 885,17–39. S. Bagheri, A. Bagheri and M. R. Nabid, Food Chem., 2014, 25 Y. Han, S. Seong Lee and J. Y. Ying, J. Chromatogr. A, 2010, 158,14–19. 1217, 4337–4343. 26 Q. Li, Z. Wu, D. Feng, B. Tu and D. Zhao, J. Phys. Chem. C, 6 F. Aydin, E. Yilmaz and M. Soylak, RSC Adv., 2015, 5, 40422– 2010, 114, 5012–5019. 27 P. Schmidt-Winkel, W. W. Lukens, J. Dongyuan Zhao, 7 Z. Wei, S. Sandron, A. T. Townsend, P. N. Nesterenko and P. Yang, B. F. Chmelka and G. D. Stucky, J. Am. Chem. Soc., B. Paull, Talanta, 2015, 135, 155–162. 1999, 121, 254–255. 8 Z. Wang, P. Mun Lee and E. Liu, Thin Solid Films, 2013, 544, 28 M. Behbahani, M. Salarian, M. M. Amini, O. Sadeghi, 341–347. A. Bagheri and S. Bagheri, Food Analytical Methods, 2013, 6, 9 M. Behbahani, P. Ghareh Hassanlou, M. M. Amini, F. Omidi, 1320–1329. A. Esrali, M. Farzadkia and A. Bagheri, Food Chem., 2015, 29 J. S. Lettow, Y. J. Han, P. Schmidt-Winkel, P. Yang, D. Zhao, 187,82–88. G. D. Stucky and J. Y. Ying, Langmuir, 2000, 16, 8291–8295. 10 E. Yilmaz and M. Soylak, Talanta, 2014, 126, 191–195. 11 M. R. Nabid, R. Sedghi, M. Behbahani, B. Arvan, 30 W. W. Lukens Jr, P. Yang and G. D. Stucky, Chem. Mater., M. M. Heravi and H. Abdi Oskooie, J. Mol. Recognit., 2014, 2001, 13,28–34. 27, 421–428. 31 P. Innocenzi, J. Non-Cryst. Solids, 2003, 316, 309–319. 12 C. Cui, M. He, B. Chen and B. Hu, Talanta, 2013, 116, 1040– 32 M. Behbahani, A. Ali Akbari, M. M. Amini and A. Bagheri, 1046. Anal. Methods, 2014, 6, 8785–8792. 13 S. Su, B. Chen, M. He and B. Hu, Talanta, 2014, 123,1–9. 33 K. Barnes, J. Liang, S. D. Worley, J. Lee, R. M. Broughton and 14 C. Kulek de Andrade, V. Eg´ea dos Anjos, M. Lurdes Felsner, T. S. Huang, J. Appl. Polym. Sci., 2007, 105, 2306–2613. Y. Reyes Torres and S. P´ercio Quin´aia, Food Chem., 2014, 146, 34 Y. Han, S. Seong Lee and J. Y. Ying, Chem. Mater., 2007, 19, 166–173. 2292–2298. 15 M. Kalate Bojdi, M. H. Mashhadizadeh, M. Behbahani, 35 E. Durduran, H. Altundag, M. Imamoglu, S. Zeki Yıldız and A. Farahani, S. S. Hosseini Davarani and A. Bagheri, M. Tuzen, J. Ind. Eng. Chem., 2015, 27, 245–250. Electrochim. Acta, 2014, 136,59–65. 36 N. Jalbani and M. Soylak, Food Chem., 2015, 167, 433–437. 37 M. Khajeh, Biol. Trace Elem. Res., 2010, 135, 355–363. 16 A. Bahrami, A. Besharati-Seidani, A. Abbaspour and 38 I. Narin, Y. Surme, E. Bercin and M. Soylak, J. Hazard. Mater., M. Shamsipur, Electrochim. Acta, 2014, 118,92–99. 2007, 145, 113–119. 17 M. Hossien-poor-Zaryabi, M. Chamsaz, T. Heidari, 39 W. Ngeontae, W. Aeungmaitrepirom and T. Tuntulani, M. H. Arbab Zavar, M. Behbahani and M. Salarian, Food Talanta, 2007, 71, 1075–1082. Analytical Methods, 2014, 7, 352–359. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68509 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png RSC Advances Royal Society of Chemistry

Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and its application as a novel mesoporous sorbent for preconcentration and trace detection of copper and cadmium ions

Download PDF
10 pages

Loading next page...
 
/lp/royal-society-of-chemistry/synthesis-and-characterization-of-diphenylcarbazide-siliceous-G0GYwmTAcR

References (39)

Datasource
Royal Society of Chemistry
Publisher site
See Article on Publisher Site

Abstract

RSC Advances PAPER Synthesis and characterization of diphenylcarbazide-siliceous mesocellular foam and Cite this: RSC Adv.,2015, 5, 68500 its application as a novel mesoporous sorbent for preconcentration and trace detection of copper and cadmium ions† a a a b Mohammad Behbahani, Azam Aliakbari, Mostafa M. Amini, Ahmad S. Behbahani and Fariborz Omidi We are introducing diphenylcarbazide functionalized siliceous mesocellular foam as a novel mesoporous solid-phase for the extraction of heavy metal ions including copper(II) and cadmium(II). The synthesized mesoporous sorbent was characterized using Fourier transform infrared spectrometry, scanning electron microscopy, elemental analysis, nitrogen adsorption–desorption isotherms and thermal analysis. Determination of the extracted ions was performed by flame atomic absorption spectrophotometry. Effects of pH value, adsorption and desorption time, type, concentration and volume of the eluent, breakthrough volume, and effect of potentially interfering ions were studied. Under optimized conditions, the extraction efficiency is >98%, and the limits of detection are 0.1, and 0.04 mgL for the ions of copper and cadmium, respectively, and the adsorption capacities for these ions are 160 and Received 30th May 2015 190 mg g . The obtained data for adsorption capacity of the sorbent shows the high tendency of the Accepted 3rd August 2015 sorbent toward the mentioned target ions. Finally, this sorbent can be used as a simple, rapid, reliable, DOI: 10.1039/c5ra10240e selective and sensitive method for the determination of trace levels of copper(II) and cadmium(II)in www.rsc.org/advances different water samples. 10–16 trace amounts of heavy metal ions in various matrices. 1. Introduction However, the direct determination of trace amounts of these ions in real samples using these techniques is challenging due Heavy metals such as cadmium and copper ions are common to matrix effects and the need for extremely low detection limits. pollutants of water, food, soil and biological samples and have Hence, sample pre-treatment, such as preconcentration of the generated intense research interest due to their toxicity to 17,18 1–4 analyzed elements and matrix separation, is oen necessary. humans, animals, and other living creatures. Hence, the A number of separation and preconcentration procedures, development of fast, reliable and effective analytical methods 19,20 21 such as solid phase extraction (SPE), coprecipitation, cloud for the determination of trace amounts of cadmium and copper 22 23 5–9 in real samples is an important area of research. point extraction (CPE) and liquid–liquid extraction (LLE), have been developed and used for the enrichment and separa- Several analytical techniques, including ame atomic tion of heavy metals at trace levels in various environmental absorption spectrometry (FAAS), electrothermal atomic samples. Among these, solid phase extraction is widely accepted absorption spectrometry (ETAAS), inductively coupled plasma as an ideal, and a powerful technique because of its simplicity, optical emission spectrometry (ICP-OES) and inductively high enrichment factor, low cost, low or no consumption of coupled plasma-mass spectrometry (ICP-MS) and electroana- organic solvents, ease of automation and ability to be coupled lytical instruments are widely used for the determination of with various modern detection techniques. Siliceous mesostructured cellular foams (MCF) is a novel mesoporous silica material template by oil-in-water micro- Department of Chemistry, Shahid Beheshti University, Evin, Tehran, Iran. E-mail: [email protected]; Fax: +98 21 22431683; Tel: +98 21 22431661 emulsions with high surface areas and well dened pore Department of Chemistry, Applied Chemistry, Shahid Beheshti University, Evin, structures have attracted considerable attention for applica- Tehran, Iran tions in catalysis, adsorption and separations. Compared to Department of Occupational Health Engineering, School of Public Health, Shahroud MCM-41 and SBA-15, MCFs prepared with the microemulsion University of Medical Sciences, Shahroud, Iran templating process by using 1,3,5-trimethylbenzene (TMB) as † Electronic supplementary information (ESI) available. See DOI: the organic swelling agent has a well-dened ultra large pores 10.1039/c5ra10240e 68500 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances (24–42 nm), a narrow pore size distribution, and three dimen- were recorded (KBr pellets) on an 8700 Shimadzu Fourier sional (3-D) pore structures. Furthermore, MCFs with uniform transform infrared (FT-IR) spectrophotometer. spherical pores interconnected by windows of around 9–22 nm 2 1 have high BET surface areas (up to 1000 m g ). Their 3-D pores 2.3. Synthesis of spherical siliceous mesocellular foam are substantially larger than those of the ordered counterparts Spherical MCF sample was synthesized by modifying the SBA-15 and MCM-41. MCFs can provide more favorable condi- conventional MCF synthesis method. In a typical preparation, tions for mass diffusion. 4.0 g of triblock copolymer Pluronic P123 were dissolved in an In this work, we have prepared organic–inorganic based acidic solution (10 mL of HCl (37%) and 65 mL of H O). A total conjugate material as an adsorbent for efficient extraction and of 4.0 g of 1,3,5-trimethylbenzene (TMB) were then added, and preconcentration of cadmium and copper ions from water the resulting solution was heated to 37–40 C with vigorous solutions. For preparation of the new class conjugate adsorbent, stirring for 2 h to synthesize the microemulsion (template). A a specic functional group of organic ligand (diphenylcarba- total of 9.2 mL of tetraethoxysilane (TEOS) was then added and zide) was successfully incorporated into siliceous mesocellular stirred for 5 min. The solution was transferred to an autoclave foam. The synthesized sorbent was characterized by Fourier and aged at 40 C for 20 h under a quiescent condition. A total of transform infrared spectroscopy, scanning electron microscopy, 46 mg of NH F was added, and the mixture was aged at 100 C elemental analysis, nitrogen adsorption–desorption isotherm for another 24 h. The resulting precipitate was ltered, washed and thermal and elemental analyses. The effects of pH, ow with water and ethanol, and dried. The white powder obtained rates, type, concentration and volume of eluent for simulta- was calcined in air at 550 C for 6 h. neous elution of copper and cadmium ions, break through volume and effect of coexisting ions on the separation and 2.4. Preparation of diphenylcarbazide functionalized MCF determination of these heavy metals were investigated. The developed method was applied for determination of copper and In this approach, in a typical reaction, 1.0 g of MCF was sus- cadmium ions in several real samples, and the accuracy of the pended in 80 mL dried toluene, and 3-chloro- method was conrmed by standard reference material. propyltriethoxysilane (4.0 mL) was added to mixture and was reuxed for 48 h under nitrogen atmosphere. The resulted white solid was suspended in 100 mL of toluene and triethyl- 2. Experimental amine mixture (3 : 1 v/v) and an excess amount of 1,5-diphe- 2.1. Chemicals nylcarbazide (1.0 g) solved in the minimum amount of acetone and then added to the reaction mixture. Aer 24 h reux the Triblock copolymer poly(ethylene oxide)-b-poly(propylene resulted solid was removed from solvent by ltration, washed oxide)-b-poly(ethylene oxide), Pluronic P123 (MW ¼ 5800), was with methanol and acetone and then dried at room tempera- purchased from Aldrich Chemical Inc. Tetraethyl orthosilicate ture. FT-IR spectroscopy, SEM, elemental and thermal analysis, (TEOS), ammonium uoride, 1,3,5-trimethylbenzene (TMB), and BET surface area measurement conrmed the synthesis of hydrogen chloride (HCl), (3-chloropropyl)triethoxysilane, MCF-diphenylcarbazide. 1,5-diphenylcarbazide, triethylamin (TEA) were purchased from Aldrich Chemical Inc. Toluene and acetone ware obtained from 2.5. Real sample pretreatment Mujallali Company (Tehran, Iran). All chemicals were used as received without any further purication. The tested water samples were tap water (Tehran, Iran), sea water (Persian Gulf and Caspian Sea) and lake water. The water samples were collected in polyethylene bottles. They were 2.2. Instrumentation cleaned with acid bath, and then ltered through nylon lters Copper and cadmium concentration was determined by an (Millipore, 0.22 mm) before the analysis. Certied reference AA-680 Shimadzu (Kyoto, Japan) ame atomic absorption material (0.1 g) were digested using 8 mL mixture of 5% aqua spectrometer (FAAS) in an air–acetylene ame, according to the regia with the assistance of a microwave digestion system. user's manual provided by the manufacturer. Copper and Digestion was carried out for 2 min at 250 W, 2 min at 0 W, cadmium hollow cathode lamps (HCL) were used as the radia- 6 min at 250 W, 5 min at 400 W, and 8 min at 550 W, and the tion source with wavelengths of 324.8 and 228.8 nm, respec- mixture was then vented for 8 min. The residue from the tively. The pH was measured at 25  1 C with a digital Metrohm digestion, as well as a controlled digestion was then diluted 827 Ion Analyzer (Herisau, Switzerland) equipped with a with deionized water. Finally, the pH of each solution was combined glass–calomel electrode. Scanning electron micros- adjusted to 7.0 by drop wise addition of HCl and NaOH for copy (SEM) was performed with a JEOL JSM-7400F electron separation and preconcentration of cadmium and copper ions microscope. The nitrogen adsorption–desorption isotherms from the water samples. were obtained using a BELSORP-mini system; the sample was degassed at 150 C for 10 h before analysis. Thermal analysis 2.6. Solid phase extraction procedure (TGA-DTA) was carried out on a Bahr STA-503 instrument in air at a heating rate of 10 C min up to 800 C. The nitrogen and Batch experiments were used for adsorption and desorption sulfur contents in the modied MCF were obtained with a studies. The dried synthesized sorbent (10 mg) was immersed in Thermo Finnigan Flash-1112EA microanalyzer. Infrared spectra a solution containing 2 mg L concentration of copper and This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68501 RSC Advances Paper cadmium ion. The pH of solution was adjusted to 7.0. Aer spherical cells. A schematic synthesis of the sorbent applied in stirring for 5 min, the solution was centrifuged and ultrapure this study is represented in Fig. 1 which contains three parts; water was used for washing of adsorbed copper and cadmium MCF synthesis, functionalization MCF with (3-chloropropyl) ions. The solid mesoporous sorbent was suspended in 2 mL of triethoxysilane (MCF-Cl) and reaction of diphenylcarbazide HCl (1 mol L ) as the eluent and stirred for 2 min. The resulted with MCF-Cl to produce (MCF-DPC). MCF synthesis in rst part solution was subsequently centrifuged and separated, and the of scheme has several stages containing emulsion formation, concentration of copper and cadmium ions was measured by the silica source putting on the template and its hydrolysis FAAS. under acidic condition and the elimination of the organic part with calcination. The pore size, window size, total pore volume and surface area of the spherical MCF sample prepared were 3. Results and discussion shown in Table 1 which characterized by N adsorption– 3.1. Characterization of the synthesized sorbent desorption isotherm. Furthermore FT-IR analysis of MCF showed a FTIR spectrum typical of silica (Fig. 2a). Spectrum MCF has a unique three-dimensional pore structure, whose presents the typical Si–O–Si bands of the inorganic framework: ultra large cell-like pores (20–50 nm) are interconnected by symmetric vibration mode around 800 cm and asymmetric 27,29,30 windows of a smaller opening (9–26 nm). The pore size stretching vibration around 1080–1100 cm . The absorption and window size of MCF could be easily controlled by using peak at 960 cm is attributed to the bending vibration of the organic swelling agent (TMB) and inorganic mineralizing agent Si–OH bands and the bands at around 1700 and 3400 cm can (NH F). However, conventional MCF consists of large, irregular be assigned to the water stretching modes and bending vibra- particles of tens of micrometers, the preparation procedure tion modes of the free or absorbed water, respectively. To applied in this article results in spherical MCF particles functionalize MCF with diphenylcarbazide, hydroxy groups on compared to the original recipe for MCF synthesis. This strategy the synthesized MCF surface was rstly reacted with silanol in the synthesis leads to synthesize MCF with spherical groups of (3-chloropropyl) triethoxysilane as a linker which is a morphology compared to conventional MCF with long straight well-established method to prepare the functionalized silica. It cylinders morphology. Actually emulsion made from oil-to- must be mentioned that there are hydroxyl groups in pore and polymer (TMB/P123) ratios above 0.2, would nally make Fig. 1 Schematic diagram of the synthesized MCF-DPC sorbent. 68502 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances Table 1 The textural properties of MCF-DPC sorbent a a 3 1 2 1 Pore size (nm) Window size (nm) Pore volume (cm g ) Surface area (m g ) Ref. MCF 29.4 17 2.1 557.3 34 MCF-DPC 25 16 1.95 480 This work The pore size and window size were derived from the adsorption branch and desorption branch of the N sorption isotherm, respectively, according to a simplied Broekhoff-de Boer method (BdB-FHH). also window parts, so the functionalization is occurred in both. Brunauer, Emmett and Teller (BET) method. Meanwhile, total 3 1 Modication with (3-chloropropyl) triethoxysilane, which is pore volume (V ,cm g ) was calculated as the amount of pore performed by condensation of –OH on MCF and ethoxy groups nitrogen adsorbed at P/P ¼ 0.990. The summary of the textural of linker, is presented in the second part of scheme (only the two properties of the prepared sorbent are shown in Table 1, which groups of linker in the pore site as an example is shown). Aer are decreased in comparing with MCF from 29.4, 17, 2.1 and modication, new bands in FT-IR spectrum at 2850–3000 cm 557.3 to 25, 16, 1.95 and 480 in pore size (nm), window size 3 1 2 1 were observed, which associated with C–H vibration (Fig. 2b). (nm), pore volume (cm g ) and surface area (m g ) respec- Last part of the scheme contains reaction of MCF-Cl with tively, indicating that incorporation of diphenylcarbazide 1,5-diphenylcarbazide by the remove of HCl, which is trapped by ligand into MCF silica supports with (3-chloropropyl) triethoxy- TEA in order to increase the reaction yield. The presence of silane as a linker. The decline in both pore and window sizes in bands at 1250–1550 cm conrmed 1,5-diphenylcarbazide MCF-DPC than MCF conrms the functionalization in both groups' immobilization on MCF-Cl (Fig. 2c). parts. As shown in Fig. 4, a typical type IV adsorption isotherm The electron microscopy studies were conducted to gain with a H hysteresis loop is obtained for MCF-DPC indicating insight in the morphology of MCF-DPC. Fig. 3 shows its image typical mesoporous materials with large pore size and narrow that clearly conrmed a spherical particle of MCF-DPC with a pore size distributions. size of about 5 mm in diameter along with some agglomeration In order to determine the loading of 1,5-diphenylcarbazide, of these particles. Furthermore, SEM indicates that the MCF the N content in this sample was measured by elemental structure aer two stages of modication hasn't changed. analyzer (CHN). The results showed 1.93% N content which is The textural properties of MCF-DPC sorbent were derived corresponds to 0.4 mmol g 1,5-diphenylcarbazide loaded on based on nitrogen adsorption–desorption data using Barrett, the MCF mesoporous. Joyner and Halenda (BJH) method to obtain the average pore The thermal stability of MCF-DPC was studied by carrying size and window size. Specic surface area was evaluated using out TGA-DTA analysis (Fig. 5). A weight loss occurred between Fig. 2 FT-IR spectra of (a) pure MCF, (b) MCF-Cl and (c) MCF-DPC. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68503 RSC Advances Paper Fig. 6 indicate that the target ions could be retained simulta- neously on functionalized MCF in the pH of 7.0. The adsorption of cadmium and copper ions by the sorbent increased from pH 2.0 to 7.0 but decreased slightly from pH 8.0 to 10.0. In the low pH, the mesoporous adsorbent was positively charged (the –N group of ligand in low pH is in the form of –NH ) and an elec- trostatic repulsion occurred between the positively charged ana- lytes and the adsorbent particles. Meanwhile, the observed decrease in retention percentage of cadmium and copper ions on the sorbent at the pH values higher than 7.0, is most probably due to the precipitation of target ions in the hydroxide form, which leads to decreasing the concentration of free cadmium and copper ions in sample. Also, in the presence of modied MCF by DPC in the extraction solution, other parameters can inuence in the retention of target ions in different pH (such as different K of complexation of ligand with target ions and viscosity of the Fig. 3 Scanning electron micrograph of MCF-DPC. solution in different pHs). Thus, pH of 7.0 was chosen as the optimum pH for further experiments. 250 C and 800 C which is accompanied with exothermic peak 3.3. Effect of the adsorbent amounts at 500 C in the DTA curve, corresponds to the oxidative decomposition of the organic part associated with 1,5-diphe- Compared to conventional sorbents, MCFs offer a signicantly nylcarbazide. Furthermore, according to thermal analysis, the higher surface area-to-volume ratio and a short diffusion route, prepared composite is stable up to 200 C. According to the 11% which results in high extraction capacity, rapid extraction weight loss in the TGA curve, the amount of ligand introduced dynamics and high extraction efficiencies. Therefore, satisfac- into MCF-DPC is 0.39 mmol g which is in good agreement tory results can be obtained with fewer amounts of these with the loading result of elemental analysis. adsorbents. For the optimization of the amount of adsorbent, 5, Overall, characterization demonstrated that the obtained 10, 15 and 20 mg of the modied MCF were tested. In the functionalized MCF possesses excellent connectivity, large present work, by increasing amounts of the modied MCF due cavities, and small and-well tailored windows, which might be to increase in the surface area and accessible sites to the eminently suitable for post application like adsorption. adsorption of the analytes, the extraction efficiency increased. Quantitative extraction of the target ions was achieved using only 10 mg of the modied MCF. At higher amounts of the 3.2. The effect of pH on retention of target ions by the adsorbent, the extraction efficiency was almost constant. synthesized mesoporous sorbent Therefore, 10 mg of the sorbent was chosen for further studies. To study the effect of pH on the extraction of target ions, the pH of 25 mL of different sample solutions containing 2 mg L of 3.4. Equilibrium sorption time each target ions was adjusted in the range of 2–10. Interaction In order to investigate the effect of shaking time on the between electron pair of –N of ligand on mesoporous sorbent and extraction efficiency, extraction experiments were carried out at target ions were affective at natural pHs. The obtained results in Fig. 4 Nitrogen sorption isotherm and corresponding pore size and window size distributions of MCF-DPC. Fig. 5 TGA-DTA analysis of MCF-DPC. 68504 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances simultaneous desorption of the target ions by 2.0 mL of the 1 mol L HCl. 3.6. Effect of sample volume Due to the low concentrations of trace metals in real samples, by using samples with large volumes, the trace metals in these volumes should be taken into smaller volumes for high pre- concentration factor. Hence, the maximum sample volume was optimized by the investigation of the recovery of target ions in various synthetic samples, volumes in the range of 25–600 mL containing 0.01 mg of targets were used to study. In the opti- mization of the sample volume, 10 mg of the sorbent was used. The recovery of targets from different volumes of aqueous solutions were shown in Fig. 7. The recovery was found to be stable until 300 mL and was chosen as the largest sample volume to this work. 3.7. Effect of potentially interfering ions Because of the presence of other elements in real samples, the determination and preconcentration of target ions is difficult. So, the effects of common coexisting cations and anions on the adsorption of the target ions on the modied MCF were inves- tigated. In these experiments, 150 mL of solution containing 0.003 mg target ions were added to interfering cations and anions and treated according to the recommended procedure. The results in Table 3 show that the vast majority of transition, alkaline, and earth alkaline metals do not interfere at environ- mentally relevant concentrations. This is due to the low capacity or rates of adsorption for interfering ions under optimum condition. Thus, these results conrm that the procedure using modied MCF is independent of matrix interferences. Fig. 6 (a) The effect of solution's pH on the retention of target ions by the mesoporous sorbent. (b) The results for the samples with only copper and cadmium ions (without adsorbent) at different pHs as a 3.8. Maximum adsorption capacity control (2 mg L of target ions was analysis without adsorbent in In order to determine how much sorbent was required to different pHs and the obtained concentration was presented). quantitatively remove a specic amount of a metal ion from the solution, the capacity of the sorbent was calculated. To evaluate this factor, 25 mL of a solution containing 2 mg target ions 2, 5, 10 and 20 min time intervals. According to the results, an underwent the extraction procedure, and the maximum equilibration time of about 5 min was required for quantitative capacity was calculated (with 10 mg of the synthesized sorbent). extraction of the target ions from solution into mesoporous The obtained capacities of modied MCF were found to be 190 solid phase. Thus, the mixtures have been shaken for 5 min to and 160 mg g for cadmium and copper ions, respectively. In reach equilibrium in the subsequent experiments. order to evaluate the maximum adsorption capacity, the difference between concentration of the solution before and the concentration of the solution aer solid phase extraction 3.5. Desorption condition procedure by the sorbent was calculated. A series of selected eluent solutions, including HNO , HCl, HNO : HCl and CH COOH were used for elution of target ions 3 3 1 3.9. Langmuir isotherm models from the modied MCF. The results show that 1 mol L HCl is a suitable and effective eluent to simultaneous elute the target In this work, Langmuir isotherms were used to measure the ions from modied MCF. The effect of eluent volume on the adsorption of copper and cadmium ions onto DPC-MCF recovery of target ions was also studied (Table 2). Also the surface. The Langmuir adsorption model is a theoretical results show, quantitative recovery could be obtained with equation and applicable to homogeneous binding sites and 2.0 mL of 1 mol L HCl. Therefore, 2.0 mL volume of eluent for assumes that the molecules are adsorbed at a xed number of desorption of target ions was used in the following experiments. well-dened sites, each of which can only hold one molecule. Desorption times were evaluated in the range of 2–10 min. These sites are also assumed to be energetically equivalent and The results showed that the time of 2 min is sufficient for distant to each other; therefore, there are no interactions This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68505 RSC Advances Paper Table 2 The effect of type, concentration, volume and time of the elution step on the extraction recovery of cadmium and copper ions a b R (%)  S Eluent Concentration (mol L ) Desorption time (min) Volume (mL) Cadmium Copper HNO 2 10 5.0 87.0  1.4 93.0  1.2 HCl 2 10 5.0 99.0  1.0 99.0  1.0 CH COOH 2 10 5.0 48.0  1.1 40.0  1.3 HNO : HCl 0.5 : 0.5 10 5.0 89.0  1.3 87.0  1.2 HCl 1.5 10 5.0 99.0  1.0 99.0  1.0 HCl 1 10 5.0 99.0  1.0 99.0  1.0 HCl 0.5 10 5.0 86.0  1.2 82.0  1.0 HCl 0.25 10 5.0 65.0  1.3 70.0  1.2 HCl 1 10 4.0 99.0  1.0 99.0  1.0 HCl 1 10 3.0 99.0  1.0 99.0  1.0 HCl 1 10 2.0 99.0  1.0 99.0  1.0 HCl 1 10 1.5 90.0  1.2 75.0  1.3 HCl 1 5 2.0 99.0  1.0 99.0  1.0 HCl 1 3 2.0 99.0  1.0 99.0  1.0 HCl 1 2 2.0 99.0  1.0 99.0  1.0 a b Recovery. Standard deviation. between molecules adsorbed on adjacent sites. The amount of adsorption capacity and energy of adsorption, respectively. The Cu(II) and Cd(II) bound by the modied mesoporous sorbent Langmuir equation can be linearized in a normal form for the was calculated according to the following formula: determination of Langmuir constants: ðC  CÞV 1 1 1 Q ¼ ¼ þ 1000W Q Q bQ C max max e where Q is the amount of adsorbed Cu(II) and Cd(II) (mg g ); C and C are the initial and nal concentrations of Cu(II) and Cd(II) Langmuir equations for copper and cadmium at pH 7 for 25 (mg L ), respectively; V is the volume of mixture (mL); and W is mL of sample volume and 10 mg of the sorbent are as follows: the amount of sorbent (g). The Langmuir adsorption isotherm is expressed by following Y ¼ 0.0078X + 0.0053 (R ¼ 0.98) equation. Langmuir equations for cadmium ions Q bC max e Q ¼ 1 þ bC e Table 3 The effect of potentially interfering ions on the extraction recovery of cadmium and copper by the synthesized mesoporous where Q is the amount of adsorbed Cu(II) and Cd(II) ions on the sorbent MCF-DPC at equilibrium (mg g ), C is the equilibrium a b concentration of Cu(II) and Cd(II) ions in solution (mg L ) and R (%)  S Tolerable concentration ratio Q and b are Langmuir constants related to the maximum max Foreign ion X/cadmium and copper ions Cadmium(II) Copper(II) K 10 000 99.0  2.0 99.0  2.0 Na 10 000 99.0  1.0 99.0  2.0 Ag 1000 97.0  1.0 96.0  1.0 Cs 1000 97.1  1.2 96.5  1.1 2+ Ca 1000 97.0  1.1 96.5  0.9 2+ Mg 1000 96.2  1.4 98.5  0.6 3+ Al 1000 97.5  1.1 97.2  1.1 2+ Fe 900 97.1  1.4 98.5  1.0 2+ Ni 600 96.5  1.5 97.1  0.9 2+ Mn 800 97.2  1.2 97.5  0.5 2+ Pb 600 97.4  0.8 98.2  1.4 3+ Cr 700 96.5  1.1 97.2  1.4 CO 1000 98.4  0.9 98.0  1.2 SO 1000 97.0  1.4 97.0  1.5 CrO 800 97.0  1.2 97.0  1.4 PO 800 98.0  1.1 97.0  1.2 Cl 3000 96.0  1.2 97.0  1.5 a b Fig. 7 The effect of sample volume on the recovery of target ions by Recovery. Standard deviation. the mesoporous sorbent. 68506 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances value is above to unity adsorption is a favorable physical process. Y ¼ 0.0082X + 0.0062 (R ¼ 0.99) 1/nF q ¼ K C can be linearized in the logarithmic form and the Langmuir equations for copper ions e F e Freundlich constants can be determined: log q ¼ log K +1/nF log C According to the relations above, adsorption capacities for e F e Cd(II) and Cu(II) were calculated to be 188.7 mg g and 161.2 mg g , respectively. The plot of log(q ) versus log(C ) was employed to generate e e Furthermore, the essential characteristic of the Langmuir the intercept value of K and the slope of 1/nF (Table 4). The isotherm can be expressed in terms of a dimensionless equi- correlation coefficients obtained from Freundlich model is librium parameter, the separation factor (RL), which used in the comparable to that obtained from Langmuir model linear form. following equation, RL ¼ 1/(1 + bC ). The value of parameter RL The values of Freundlich constant 1/nF is between 0 and 1.0 indicates the nature of the adsorption process which irrevers- which also indicated that adsorption of cadmium (0.86) and ible (RL ¼ 0), favorable (0 < RL < 1), linear (RL ¼ 1), or unfa- copper (0.7) ions under the studied condition are suitable. vorable (RL > 1). The value of RL for the present system comes A comparison of the two isotherms based on the linear out to be 0.018 and 0.02 for cadmium and copper, respectively, regression coefficient (R ) values showed that the sorption of communicating the favorable adsorption of the target ions onto target ions on DPC-MCF nearly similar results (R ) for both DPC-MCF. Langmuir and Freundlich isotherm models, under the concentration range studied. 3.10. Freundlich isotherm model The Freundlich isotherm model is the earliest known relation- 3.11. Analytical performance ship describing the sorption process. The model applies to Under the optimized conditions, calibration curves were adsorption on heterogeneous surfaces with interaction between sketched for the determination of cadmium and copper ions adsorbed molecules and the application of the Freundlich according to the optimum extraction procedure. Linearity was equation also suggests that sorption energy exponentially 1 1 maintained 0.5–200 mgL for copper and 0.1–30 mgL for decreases on completion of the sorptional centers of an adsor- cadmium in initial solution (150 mL of sample). The correlation bent. This isotherm is an empirical equation can be employed of determination (R ) was 0.99 for copper and 0.99 for cadmium to describe heterogeneous systems and is expressed as follow: ions. The limit of detection, which is dened as C ¼ 3S /m, LOD b 1/nF q ¼ K C where S is the standard deviation of eight replicate blank e F e b signals and m is the slope of the calibration curve aer pre- where K is the Freundlich constant (L g ) related to the bonding concentration, for a sample volume of 150 mL, was found to be 1 1 energy. K can be dened as the adsorption or distribution coef- 0.1 mgL for copper and 0.04 mgL for cadmium ions, cient and represents the quantity of ions adsorbed onto adsor- respectively. The relative standard deviations for eight separate bent for unit equilibrium concentration. 1/nF is the heterogeneity experiments for determination of 7.5 mg of cadmium and factor and nF is a measure of the deviation from linearity of copper ions in 150 mL of water was 2.5 and 3.1, respectively. adsorption. Its value indicates the degree of non-linearity between Regression equation, dynamic linear range (DLR), correlation of solution concentration and adsorption as follows: if the value of determination (R ), preconcentration factor (PF), limit of nF is equal to unity, the adsorption is linear; if the value is below detection (LOD) and relative standard deviation (RSD) for to unity, this implies that adsorption process is chemical; if the cadmium and copper were calculated under optimized condi- tions and summarized in Table 5. Since 150 mL of the solution was preconcentrated to 2.0 mL, Table 4 The obtained data from Freundlich isotherm model the approximately preconcentration factor of 75 was obtained. Ion Freundlich model R K nF 3.12. Real sample analysis Cadmium Y ¼ 0.86X + 1.92 0.97 83.2 1.16 Finally, this method was performed on real samples to check its Copper Y ¼ 0.71X + 1.77 0.98 58.9 1.4 accuracy. Since the amounts of cadmium and copper ions in Table 5 Regression equation, dynamic linear range (DLR), correlation of determination (R ), preconcentration factor (PF), limit of detection (LOD) and relative standard deviation (RSD) for copper and copper were calculated under optimized conditions 2 1 1 b b a 1 Analyte Regression equation r LOD (ng mL ) DLR (ng mL ) PF Recovery (%) RSD (%) MAC (mg g ) Copper ion Y ¼ 8.53X (mg L ) + 0.001 0.99 0.1 0.5–200 75 >98 3.1 160 Cadmium ion Y ¼ 51.75X (mg L ) + 0.0004 0.99 0.04 0.01–20 75 >98 2.5 190 a b 1 Maximum sorption capacity. Recovery and RSD is calculated for 50 mgL of copper and cadmium ions. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68507 RSC Advances Paper Table 6 Analysis of copper and cadmium ion in different food samples cadmium ions was determined at optimum conditions in standard reference material (Soil (NCS DC 73323)). As it can Added Founded RR RSD be seen in Table 1S (ESI†), good correlation was achieved 1 1 Sample Ion (mgL ) (mgL ) (%) (%) between estimated content by the present method and refer- Tap water Copper — 10.2 — 2.1 ence materials. Therefore, modied MCF with diphe- 5.0 15.2 100.0 2.8 nylcarbazide can be used as a reliable solid phase for 50.0 59.5 98.6 2.6 extraction and determination of copper and cadmium ions in Cadmium —— — — real samples. 5.0 5.1 102.0 2.9 50.0 49.8 99.6 2.9 Caspian sea water Copper — 19.8 — 2.6 4. Conclusions 5.0 24.7 98.0 3.1 50.0 69.9 100.2 2.8 S-MCF microparticles with a spherical morphology and a Cadmium — 7.1 — 2.8 narrow particle size distribution were prepared by a simple 5.0 12.0 98.0 3.1 modication of the conventional MCF synthesis. The pore 50.0 56.9 99.6 2.7 Persian Gulf water Copper — 18.3 — 1.9 sizes and surface areas of S-MCF particles could be adjusted 5.0 23.4 102.0 2.7 without affecting the particle morphology. The S-MCF parti- 50.0 68.1 99.6 2.4 cles were functionalized with diphenylcarbazide groups, and Cadmium — 6.6 — 2.5 applied as a new class mesoporous sorbent for simultaneous 5.0 11.7 102.0 2.9 separation and trace detection of copper and cadmium ions 50.0 56.5 99.8 2.2 Lake water Copper — 15.2 — 2.1 in environmental water samples. Their high surface areas 5.0 20.3 102.0 2.8 gave rise to very good retention ability, as illustrated in the 50.0 64.9 99.4 3.1 separation of cadmium and copper ions. The highly inter- Cadmium — 2.3 — 2.7 connected porous structure and ultra large pore size allowed 5.0 7.3 100.0 2.5 MCF to be used as a sorbent for rapid extraction of ions and 50.0 52.1 99.6 2.5 molecules. In this work, for the rst time, modied MCF with diphenylcarbazide was utilized as an adsorbent for the simultaneous separation of ultra-trace amounts of cadmium and copper ions. This method is simple, rapid and reliable real samples are too low, some amount of the target ions was and found as a selective and sensitive method for the deter- also spiked in these samples. To test the reliability of the mination of trace levels of cadmium and copper ions. The method for extraction and determination of the target ions in convenient data was found for adsorption capacity, detection the environmental water samples were applied. The results limit and pre-concentration factor in the determination of demonstrate that quantitative recoveries of the target ions for the target ions and conrmed that this method using modi- modied MCF with diphenylcarbazide are achievable. The ed MCF with diphenylcarbazide has a high potential for results are listed in Table 6. extraction of metal ions. As a result, the LOD, pre- The concentration of copper and cadmium ions obtained concentration factor and maximum adsorption capacity of by modied MCF was compared to the standard reference this method is better than some of the previously reported material. For this reason, the concentration of the copper and 35–39 pre-concentration methods (Table 7). Table 7 Comparison of the proposed method with previously published work related to the extraction and determination of cadmium and copper ions 1 a b Instrument Method Elements LOD (ng mL)PF MAC Ref. ICP-OES AEDHB-SG sorbent Cadmium 0.012 100 0.40 mmol g 35 Copper 0.098 100 0.56 mmol g FAAS UA-IL-DLLME Cadmium —— — 36 Copper 0.17 100 — ICP-OES Morin-magnetic nanoparticle Cadmium —— — 37 Copper 0.9 28 — FAAS Chelating resin Cadmium 4.2 100 — 38 Copper —— — FAAS Modied silica gel Cadmium 1.1 27 0.067 mmol g 39 Copper 1.0 27 0.30 mmol g FAAS Diphenylcarbazide-MCF Cadmium 0.04 75 190 mg g This work Copper 0.1 75 160 mg g a b Preconcentration factor. Maximum adsorption capacity. 68508 | RSC Adv.,2015, 5,68500–68509 This journal is © The Royal Society of Chemistry 2015 Paper RSC Advances 18 M. H. Karbasi, B. Jahanparast, M. Shamsipur and J. Hassan, References J. Hazard. Mater., 2009, 170, 151–155. 19 Z. A. Alothman, E. Yilmaz, M. Habila and M. Soylak, 1 G. Somer, A. N. Unlu, S. Kalayci and F. Sahin, Turk. J. Chem., 2006, 30, 419–427. Ecotoxicol. Environ. Saf., 2015, 112,74–79. 2 A. Bagheri, M. Taghizadeh, M. Behbahani, 20 H. R. Fouladian and M. Behbahani, Food Analytical Methods, A. A. Asgharinezhad, M. Salarian, A. Dehghani, 2015, 8, 982–993. H. Ebrahimzadeh and M. M. Amini, Talanta, 2012, 99, 132– 21 B. Feist and B. Mikula, Food Chem., 2014, 147, 225–229. 139. 22 S. Aslam Arain, T. G. Kazi, H. I. Afridi, A. R. Abbasi, 3 A. Bagheri, M. Behbahani, M. M. Amini, O. Sadeghi, A. H. Panhwar, Naeemullah, B. Shanker and M. B. Arain, M. Taghizade, L. Baghayi and M. Salarian, Talanta, 2012, Spectrochim. Acta, Part A, 2014, 133, 651–656. 89, 455–461. 23 G. Helle, C. Mariet and G. Cote, Talanta, 2015, 139, 123–131. 4 N. Jalbani and M. Soylak, Talanta, 2015, 131, 361–365. 24 C. F. Poole, A. D. Gunatilleka and R. Sethuraman, J. 5 M. Behbahani, Y. Bide, M. Salarian, M. Niknezhad, Chromatogr. A, 2000, 885,17–39. S. Bagheri, A. Bagheri and M. R. Nabid, Food Chem., 2014, 25 Y. Han, S. Seong Lee and J. Y. Ying, J. Chromatogr. A, 2010, 158,14–19. 1217, 4337–4343. 26 Q. Li, Z. Wu, D. Feng, B. Tu and D. Zhao, J. Phys. Chem. C, 6 F. Aydin, E. Yilmaz and M. Soylak, RSC Adv., 2015, 5, 40422– 2010, 114, 5012–5019. 27 P. Schmidt-Winkel, W. W. Lukens, J. Dongyuan Zhao, 7 Z. Wei, S. Sandron, A. T. Townsend, P. N. Nesterenko and P. Yang, B. F. Chmelka and G. D. Stucky, J. Am. Chem. Soc., B. Paull, Talanta, 2015, 135, 155–162. 1999, 121, 254–255. 8 Z. Wang, P. Mun Lee and E. Liu, Thin Solid Films, 2013, 544, 28 M. Behbahani, M. Salarian, M. M. Amini, O. Sadeghi, 341–347. A. Bagheri and S. Bagheri, Food Analytical Methods, 2013, 6, 9 M. Behbahani, P. Ghareh Hassanlou, M. M. Amini, F. Omidi, 1320–1329. A. Esrali, M. Farzadkia and A. Bagheri, Food Chem., 2015, 29 J. S. Lettow, Y. J. Han, P. Schmidt-Winkel, P. Yang, D. Zhao, 187,82–88. G. D. Stucky and J. Y. Ying, Langmuir, 2000, 16, 8291–8295. 10 E. Yilmaz and M. Soylak, Talanta, 2014, 126, 191–195. 11 M. R. Nabid, R. Sedghi, M. Behbahani, B. Arvan, 30 W. W. Lukens Jr, P. Yang and G. D. Stucky, Chem. Mater., M. M. Heravi and H. Abdi Oskooie, J. Mol. Recognit., 2014, 2001, 13,28–34. 27, 421–428. 31 P. Innocenzi, J. Non-Cryst. Solids, 2003, 316, 309–319. 12 C. Cui, M. He, B. Chen and B. Hu, Talanta, 2013, 116, 1040– 32 M. Behbahani, A. Ali Akbari, M. M. Amini and A. Bagheri, 1046. Anal. Methods, 2014, 6, 8785–8792. 13 S. Su, B. Chen, M. He and B. Hu, Talanta, 2014, 123,1–9. 33 K. Barnes, J. Liang, S. D. Worley, J. Lee, R. M. Broughton and 14 C. Kulek de Andrade, V. Eg´ea dos Anjos, M. Lurdes Felsner, T. S. Huang, J. Appl. Polym. Sci., 2007, 105, 2306–2613. Y. Reyes Torres and S. P´ercio Quin´aia, Food Chem., 2014, 146, 34 Y. Han, S. Seong Lee and J. Y. Ying, Chem. Mater., 2007, 19, 166–173. 2292–2298. 15 M. Kalate Bojdi, M. H. Mashhadizadeh, M. Behbahani, 35 E. Durduran, H. Altundag, M. Imamoglu, S. Zeki Yıldız and A. Farahani, S. S. Hosseini Davarani and A. Bagheri, M. Tuzen, J. Ind. Eng. Chem., 2015, 27, 245–250. Electrochim. Acta, 2014, 136,59–65. 36 N. Jalbani and M. Soylak, Food Chem., 2015, 167, 433–437. 37 M. Khajeh, Biol. Trace Elem. Res., 2010, 135, 355–363. 16 A. Bahrami, A. Besharati-Seidani, A. Abbaspour and 38 I. Narin, Y. Surme, E. Bercin and M. Soylak, J. Hazard. Mater., M. Shamsipur, Electrochim. Acta, 2014, 118,92–99. 2007, 145, 113–119. 17 M. Hossien-poor-Zaryabi, M. Chamsaz, T. Heidari, 39 W. Ngeontae, W. Aeungmaitrepirom and T. Tuntulani, M. H. Arbab Zavar, M. Behbahani and M. Salarian, Food Talanta, 2007, 71, 1075–1082. Analytical Methods, 2014, 7, 352–359. This journal is © The Royal Society of Chemistry 2015 RSC Adv.,2015, 5,68500–68509 | 68509

Journal

RSC Advances – Royal Society of Chemistry

Published: Aug 11, 2015

There are no references for this article.