Lead adsorption of zinc oxide-coated ACOR montmorillonite was investigated in batches and under reducing conditions at ambient temperature. The presence of zinc oxide coating significantly enhanced the adsorption of P...Lead adsorption of zinc oxide-coated ACOR montmorillonite was investigated in batches and under reducing conditions at ambient temperature. The presence of zinc oxide coating significantly enhanced the adsorption of Pb^(2+) ions by ACOR montmorillonite. Characterization of adsorbents involved the use of X-ray diffraction, sodium saturation techniques, coulter laser analysis, scanning electron microscopy, and electron dispersive spectroscopy.Synthesis involved the trimetric process, activation of the ACOR montmorillonite and reacting of the same with zinc nitrate to produce a zinc oxide composite solid at 450 °C.The reaction mechanism indicated less than one proton coefficient, and higher mass transfer rates, when compared with bare montmorillonite. Intraparticle diffusion was higher than the value recorded for the bare montmorillonite. Reactions based on initial Pb^(2+) concentration indicated that coated montmorillonite gradually became saturated as the concentration was increased. Reactions based on solid concentration demonstrated a complex change in the capacity of adsorption over different Pb^(2+) concentrations(10–40 mg L^(-1)) and solid concentrations(2–10 g L^(-1)). The specific surface area reduction, particle size increase, mineral aggregation, and concentration gradient effect controlled the complex changes in adsorption.展开更多
A rapid method for the extraction and monitoring of nanogram level of Pbz＋ and Cuz＋ ions using uniform silanized mesopor （SBA-15） functionalized with aminobenzenesulfonamide groups and flame atomic absorption spec...A rapid method for the extraction and monitoring of nanogram level of Pbz＋ and Cuz＋ ions using uniform silanized mesopor （SBA-15） functionalized with aminobenzenesulfonamide groups and flame atomic absorption spectrometry （FAAS） is presented. Aminobenzenesulfonamide functionalized SBA-15 was synthesized according to procedure in the literature and the presence of organic groups in the silica framework was demonstrated by FT-IR spectra. The functionalized product showed the BET surface area 110 mZ/g and pore diameter 5. l nm, based on adsorption-desorption of N2 at 77 K. The effect of several variables such as （amount of adsorbent, stirring time, pH and presence of other ions in the medium） has been studied. Lead and copper were completely extracted at pH greater than 3 after stirring for 10 min. The maximum capacity of the adsorbent was found to be 191.3 ＋ 1.4 and 155.0 ＋ 1.0 ~xg of lead and copper ions/mg functionalized SBA-15, respectively. The preconcentration factor of the method was found to be 200. The detection limit of the technique was 3.4 and 0.4 ng/mL for Pb2＋ and Cuz＋, respectively. The applications of this methodology for real samples were examined by various water type, black tea and pepper samples.展开更多
基金the Niger Delta University for the usual research allowances provided for the running of research projects
文摘Lead adsorption of zinc oxide-coated ACOR montmorillonite was investigated in batches and under reducing conditions at ambient temperature. The presence of zinc oxide coating significantly enhanced the adsorption of Pb^(2+) ions by ACOR montmorillonite. Characterization of adsorbents involved the use of X-ray diffraction, sodium saturation techniques, coulter laser analysis, scanning electron microscopy, and electron dispersive spectroscopy.Synthesis involved the trimetric process, activation of the ACOR montmorillonite and reacting of the same with zinc nitrate to produce a zinc oxide composite solid at 450 °C.The reaction mechanism indicated less than one proton coefficient, and higher mass transfer rates, when compared with bare montmorillonite. Intraparticle diffusion was higher than the value recorded for the bare montmorillonite. Reactions based on initial Pb^(2+) concentration indicated that coated montmorillonite gradually became saturated as the concentration was increased. Reactions based on solid concentration demonstrated a complex change in the capacity of adsorption over different Pb^(2+) concentrations(10–40 mg L^(-1)) and solid concentrations(2–10 g L^(-1)). The specific surface area reduction, particle size increase, mineral aggregation, and concentration gradient effect controlled the complex changes in adsorption.
基金the Islamic Azad University, Shahre Rey Branch, for the support
文摘A rapid method for the extraction and monitoring of nanogram level of Pbz＋ and Cuz＋ ions using uniform silanized mesopor （SBA-15） functionalized with aminobenzenesulfonamide groups and flame atomic absorption spectrometry （FAAS） is presented. Aminobenzenesulfonamide functionalized SBA-15 was synthesized according to procedure in the literature and the presence of organic groups in the silica framework was demonstrated by FT-IR spectra. The functionalized product showed the BET surface area 110 mZ/g and pore diameter 5. l nm, based on adsorption-desorption of N2 at 77 K. The effect of several variables such as （amount of adsorbent, stirring time, pH and presence of other ions in the medium） has been studied. Lead and copper were completely extracted at pH greater than 3 after stirring for 10 min. The maximum capacity of the adsorbent was found to be 191.3 ＋ 1.4 and 155.0 ＋ 1.0 ~xg of lead and copper ions/mg functionalized SBA-15, respectively. The preconcentration factor of the method was found to be 200. The detection limit of the technique was 3.4 and 0.4 ng/mL for Pb2＋ and Cuz＋, respectively. The applications of this methodology for real samples were examined by various water type, black tea and pepper samples.
