In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The sc...In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities （qe） of Pb^2＋ and Cd^2＋ was synthesized with the following conditions： Addition of pillaring solution containing Al3＋-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na＋-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2＋ and Cd^2＋ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.展开更多
In this work,the efficiency of an adsorption process,in which Moroccan diatomite(ND)is used as a low-cost adsorbent to remove Congo red(CR)dye from contaminated waters in batch and column system,was examined.The influ...In this work,the efficiency of an adsorption process,in which Moroccan diatomite(ND)is used as a low-cost adsorbent to remove Congo red(CR)dye from contaminated waters in batch and column system,was examined.The influence of experimental conditions(pH,adsorbent dose and temperature)on the adsorption of CR onto the ND adsorbent was studied.A study of the adsorption kinetics for CR revealed that a pseudo-second-order model provided the best fit to the experimental kinetic data,and the equilibrium data were well described by the Langmuir isotherm model with an adsorption capacity of 6.07 mg/g using 15 g/L of ND,pH=6,contact time 3 h and 25℃.On the other hand,the ND regeneration tests were investigated and showed that the desorption reaches at least 50%when using ethanol as eluent.In addition,the adsorption process in a continuous mode was studied.Breakthrough curves were properly represented by the Yoon—Nelson model.Hence,the adsorption capacity of 5.71 mg/g was reached using 0.114 g of adsorbent,CR concentration of 6 mg/L and a flow of 1 mL/min under 25℃.展开更多
基金Project(12JJ8016)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(CX2012B317)supported by Hunan Provincial Innovation Foundation For Postgraduate,ChinaProject(2006180)supported by the Hunan Key Discipline Construction Found of Environmental Science,China
文摘In order to greatly improve adsorption capacity, the diatomite was pillared by polyhydroxyl-aluminum.A series of adsorption tests were conducted to obtain the optimum condition for pillared diatomite synthesis. The scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, surface area and porosity analyzer and micro-electrophoresis were used to determine pore structure and surface property.The pillared diatomite attaining the optimal adsorption densities （qe） of Pb^2＋ and Cd^2＋ was synthesized with the following conditions： Addition of pillaring solution containing Al3＋-oligomers with a concentration range of 0.1-0.2 mol/L to a suspension containing Na＋-diatomite to obtain the required Al/diatomite ratio of 10 mmol/g; synthesis temperature of 80 ℃ for 120 min; aging at a temperature of 105 ℃ for 16 h. The adsorption capacities of Pb^2＋ and Cd^2＋ on pillared diatomite increase by 23.79% and 27.36% compared with natural diatomite, respectively. The surface property of pillared diatomite is more favorable for ion adsorption than natural diatomite. The result suggests that diatomite can be modified by pillaring with polyhydroxyl-aluminum to improve its adsorption properties greatly.
文摘In this work,the efficiency of an adsorption process,in which Moroccan diatomite(ND)is used as a low-cost adsorbent to remove Congo red(CR)dye from contaminated waters in batch and column system,was examined.The influence of experimental conditions(pH,adsorbent dose and temperature)on the adsorption of CR onto the ND adsorbent was studied.A study of the adsorption kinetics for CR revealed that a pseudo-second-order model provided the best fit to the experimental kinetic data,and the equilibrium data were well described by the Langmuir isotherm model with an adsorption capacity of 6.07 mg/g using 15 g/L of ND,pH=6,contact time 3 h and 25℃.On the other hand,the ND regeneration tests were investigated and showed that the desorption reaches at least 50%when using ethanol as eluent.In addition,the adsorption process in a continuous mode was studied.Breakthrough curves were properly represented by the Yoon—Nelson model.Hence,the adsorption capacity of 5.71 mg/g was reached using 0.114 g of adsorbent,CR concentration of 6 mg/L and a flow of 1 mL/min under 25℃.
