六氯苯在红壤和黄泥土上的依时解吸特征  

Time-dependent Desorption Characteristics of Hexachlorobenzene(HCB) from Red Soil and Huangni Soil

作　　者：郜红建[1] 蒋新[2] 常江[1] 张自立[1] 章力干[1] 

机构地区：[1]安徽农业大学资源与环境学院,安徽合肥230036 [2]中国科学院南京土壤研究所,江苏南京210008

出　　处：《农业环境科学学报》2007年第2期588-591,共4页Journal of Agro-Environment Science

基　　金：国家重点基础发展规划项目(2002CB410805);安徽高校省级自然科学研究项目(2006KJ175B);安徽省高校青年教师科研资助计划项目(2006JQL119)

摘　　要：采用批量平衡实验和动态实验的方法,研究了六氯苯在红壤和黄泥土上的吸附和依时解吸特征。结果表明,六氯苯在红壤和黄泥土上的吸附与解吸行为可用Freundlich方程进行拟合,并表现非线性特征。六氯苯从这两种土壤上解吸的过程受解吸时间的影响,随着解吸时间的延长,六氯苯吸附等温线与解吸等温线的差异变大,表现出一定的滞后效应。用不同方程对滞后系数H和λ进行量化发现,随着解吸时间的延长,和吸附强度有关的参数Kdes逐渐增大,滞后效应增强。Sorption and time-dependent desorption characteristics of HCB in red soil and Huangni soil were investigated by using the kinetic batch experiments with wide range of initial concentrations （from 0.25 to 5.0 mg · L^-1）. Five successive desorption steps （10 d） were carried out after sorption experiments. The results revealed that the adsorption and desorption isotherms of HCB in two soils could be best described by Freundlich equations, which were highly nonlinear, with a Freundlich reaction order n less than 1（0.71-0.79）. The Freundlich adsorption capacity parameters Krfor desorption （10.45 L. kg^-1 and 11.54 L. kg^-1） were higher than those associated with adsorption （8.62 L. kg^-1 and 10.52 L.kg^-1） in red soil and Huangni soil, respectively. The distinct discrepancies between adsorption and desorption isotherms clearly indicated considerable desorption hysteresis for HCB in two soils. Desorption hysteresis coefficient could be described by H, based on the ratio of desorption and adsorption isotherm parameter n, and λ, based on the difference in the area between the adsorption and desorption isotherms. For the time-dependent desorption isotherms, ）t increased as desorption time prolonged, which is indicative of difficulty to desorb HCB from soils. This observed hysteresis might be due to the existence of irreversible reaction, which caused a decrease of desorbed HCB amount as desorption time increased.

关 键 词：六氯苯 土壤 解吸特征 滞后效应 

分 类 号：X592[环境科学与工程—环境工程]