天然土壤对水溶液中Pb^(2+)的吸附

Adsorption of Pb^(2+) in aqueous solution by natural soils

以天然土壤为吸附材料,处理水溶液中的Pb2+,研究3种土壤对水溶液中Pb2+的吸附过程并结合土壤的理化性质对吸附规律进行初步分析。结果表明,棕壤和钙层土对Pb2+的吸附能力远大于红壤,3种土壤对Pb2+的吸附动力学曲线与二次动力学方程有较好的拟合性;3种土壤吸附Pb2+的吸附等温线用Langmuir方程描述最为合适,其次是Temkin方程,再次是Frenudlich方程,钙层土对Pb2+的吸附受温度影响较为明显;由实验数据得出的反应热力学参数说明3种土壤对Pb2+的吸附是自发的吸热过程;Pb2+在饱和吸附的土壤表面覆盖率并不高;土壤对Pb2+的吸附能力受各种土壤理化性质的综合影响。

Natural soils were used to adsorb Pb2 +in aqueous solution. Adsorption processes of Pb2 +on three soils in aqueous solution were studied,and the law of adsorption was preliminarily analyzed according to the basic physico-chemical properties of soil samples. The results indicated that the sorption capacities of brown soil and pedocal were much higher than that of red soil,and the adsorption kinetic curves of Pb2 +on studied soils fitted secondary dynamics equation well. Langmuir equation was the best model to describe theadsorption isotherms of Pb2 +on three soils,followed by Temkin equation and Frenudlich equation. The adsorption of Pb2 +on pedocal was affected by temperature significantly. Thermodynamic parameters obtained from experimental data showed that the adsorption processes were spontaneous and endothermic. Surface covered fractions of Pb2 +on adsorption saturated soils were not high enough,and the Pb2 +sorption capacities of soils were synthetically affected by a variety of soils' physico-chemical properties.