PEI-DTC的制备及其对Pb^(2+)、Cu^(2+)、Zn^(2+)的吸附性能

Preparation of PEI-DTC and its adsorption performance on Pb^(2+),Cu^(2+),Zn^(2+)

以Pb^(2+)吸附量为评价指标获得了PEI-DTC的最佳制备条件,采用SEM和FT-IR对所制备材料的形貌和结构进行了表征,考察了吸附时间、pH、振荡速度和材料投量对PEI-DTC吸附Pb^(2+)、Cu^(2+)、Zn^(2+)效果的影响,分析了吸附过程中的动力学特征、热力学特征,研究了材料的复用性能。结果表明,采用30%PEI溶液制备PEI-DTC的最佳条件为m(PEI)/m(戊二醛)=2:1、m(PEI)/m(硼氢化钠)=3:1、m(PEI)/m(二硫化碳)=3:1;所制备材料表面呈颗粒状和蜂窝状结构,比表面积较大;PEI-DTC对Pb^(2+)、Cu^(2+)、Zn^(2+)的吸附效果随吸附时间、溶液pH增加呈先快速增加后趋于稳定的变化趋势,Pb^(2+)、Cu^(2+)在100 r·min^(-1)、Zn^(2+)在150 r·min^(-1)时表现出较好的吸附效果,Pb^(2+)在材料投量为0.03 g时即近于完全吸附,而Cu^(2+)、Zn^(2+)在材料投量为0.08 g时仍处于上升趋势;适宜吸附条件下PEI-DTC对Pb^(2+)、Zn^(2+)、Cu^(2+)的去除率分别可达97.62%、14.79%、78.92%,对应的吸附量分别为4.005、0.509、4.658 mmol·g^(-1);PEI-DTC对Pb^(2+)、Zn^(2+)、Cu^(2+)的吸附过程符合Langmuir模型和准二级反应动力学模型,吸附为自发的吸热过程;经4次使用,材料对Pb^(2+)的吸附量仍保留81.14%。

The optimum preparation conditions of PEI-DTC were obtained by taking the adsorption amount of Pb^(2+) as the evaluation index,and the morphology and structure of PEI-DTC were characterized by SEM and FTIR.The effects of adsorption duration,pH,oscillation speed,and material dosage on the adsorption effect of PEI-DTC to Pb^(2+),Cu^(2+),and Zn^(2+) were investigated,and the kinetic,thermodynamic characteristics of the adsorption process,and reuse performance of PEI-DTC were analyzed.The results showed that the optimum preparation conditions of PEI-DTC were m(PEI)/m(glutaraldehyde)=2:1,m(PEI)/m(NaBH)=3:1,m(PEI)/m(CS2)=3:1 when 30% PEI solution was used.The prepared PEI-DTC material had a granular and honeycomb structure with a large specific surface area.The adsorption effect of PEI-DTC on Pb^(2+),Cu^(2+),and Zn^(2+) showed a trend of increasing and then stabilizing with the increase of adsorption time and pH,Pb^(2+),Cu^(2+)showed a better adsorption effect at the oscillations speed of 100 r·min^(-1),and Zn^(2+) showed a better adsorption effect at the oscillations speed of 150 r·min^(-1).Pb^(2+) was nearly completely adsorbed at PEI-DTC dosage of 0.03g,while the removal rates of Cu^(2+) and Zn^(2+) still increased at PEI-DTC dosage of 0.08 g.The removal rates of Pb^(2+),Zn^(2+),and Cu^(2+) by PEI-DTC under suitable adsorption conditions were 97.62%,14.79%,and 78.92%,respectively,with the corresponding adsorption amounts of 4.005 mmol·g^(-1),0.509 mmol·g^(-1),and 4.658mmol·g^(-1),respectively.The adsorption process conformed to Langmuir adsorption isothermal and the quasisecond-order kinetic model.Moreover,Pb^(2+),Cu^(2+),and Zn^(2+) adsorption was a spontaneous and endothermic process.The regeneration rate still maintained at 81.14% after four cycles of reuse.