自养硝化颗粒污泥吸附铅离子机理研究

Adsorption mechanism of lead ion by autotrophic nitrifying granular sludge

为高效去除无机废水中铅离子,利用Langmuir方程、准一级动力学和准二级动力学拟合自养硝化颗粒污泥(ANGS)对铅离子的吸附过程,再对吸附前后的ANGS进行FTIR、XPS及XRD表征,探究ANGS吸附铅离子的吸附机理。Langmuir方程的R2=0.9984,最大吸附容量为39.84 mg/g,即吸附过程属于单分子层吸附。用准一级动力学和准二级动力学模型拟合计算ANGS对铅离子的吸附速率,R^(2)分别为0.9699和0.9995,但拟二级动力学模型计算出的平衡吸附量更接近实测值(误差为5.01%),表明ANGS对铅离子吸附过程中的控制步骤为化学吸附。吸附前后ANGS的结构和形貌无明显变化,ANGS吸附铅离子的机理为离子交换、静电吸附和表面络合。

In order to achieve efficient removal of lead ions from inorganic wastewater,langmuir equation,quasi-first-order kinetics and quasi-second-order kinetics were used to fit the adsorption process of lead ions by autotrophic nitrifying granular sludge(ANGS),and then the ANGS before and after adsorption was characterized by FTIR,XPS and XRD to explore the adsorption mechanism of lead ion by ANGS.The R2=0.9984 and maximum adsorption capacity of Langmuir equation 39.84 mg/g,which means the adsorption process belongs to monolayer adsorption.The adsorption rate of lead ion by ANGS was studied by quasi-first-order kinetic model and quasi-second-order kinetic model,R^(2) was 0.9699 and 0.9995 respectively.The equilibrium adsorption calculated by the quasi-second-order kinetic model was closer to the measured value(error of 5.01%),indicating that the control step of ANGS in the process of lead ion adsorption is chemical adsorption.The structure and morphology of ANGS have no obvious change before and after adsorption.After characterization and analysis,it is considered that the mechanism of lead ion adsorption by ANGS is ion exchange,electrostatic adsorption and surface complexation.