摘要
Pb2＋ adsorption onto a soil by irrigation of sewage in the Pearl River Delta of South China was examined as a function of the reaction time, solution pH, initial lead concentration, organic matter （humic acid） and competitive ions （Cu2＋）. The adsorption of Pb2＋ onto the soil was investigated on batch equilibrium adsorption experiments. Results show that the Pb2＋ adsorption on the soil is relatively rapid in the first 30 min and reaches equilibrium at 2 h, and the kinetics of the adsorption process on the soil is well characterized by the pseudo-second order reaction rate. Langmuir, Freundlich and Temkin isothermal models are fit for the adsorption of Pb2＋ onto the soil, and the maximum amount of Pb2＋ adsorption （Qm） is 7.47 mg/g. The amount of Pb2＋ adsorption increases with increasing the pH at the range of 1.2-4.5 and reaches a plateau at the range of 4.5-12. The presence of humic acid in soil decreases the adsorption of Pb2＋ onto the soil at solution pH of 8 since the negatively charged humic acid with Pb2＋ is difficult to be adsorbed on the negatively charged soil surface. The adsorption of Pb2＋ onto the soil also decreases in the presence of Cu2＋ due to file competition adsorption between Pb2＋ and Cu2＋.
Pb2+ adsorption onto a soil by irrigation of sewage in the Pearl River Delta of South China was examined as a function of the reaction time,solution pH,initial lead concentration,organic matter(humic acid) and competitive ions(Cu2+).The adsorption of Pb2+ onto the soil was investigated on batch equilibrium adsorption experiments.Results show that the Pb2+ adsorption on the soil is relatively rapid in the first 30 min and reaches equilibrium at 2 h,and the kinetics of the adsorption process on the soil is well characterized by the pseudo-second order reaction rate.Langmuir,Freundlich and Temkin isothermal models are fit for the adsorption of Pb2+ onto the soil,and the maximum amount of Pb2+ adsorption(Qm) is 7.47 mg/g.The amount of Pb2+ adsorption increases with increasing the pH at the range of 1.2-4.5 and reaches a plateau at the range of 4.5-12.The presence of humic acid in soil decreases the adsorption of Pb2+ onto the soil at solution pH of 8 since the negatively charged humic acid with Pb2+ is difficult to be adsorbed on the negatively charged soil surface.The adsorption of Pb2+ onto the soil also decreases in the presence of Cu2+ due to the competition adsorption between Pb2+ and Cu2+.
基金
Project(SK201109) supported by the Basic Scientific Study Funding from Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Sciences
Project(2010CB428806-2) supported by the National Basic Research Program of China
