山阴地区浅层沉积物中砷的分布特征及吸附行为  

Distribution characteristics and adsorption behavior of arsenic on shallow sediments in Shanyin region

作　　者：邓天天[1] 李义连[1] 田蓉[1] 

机构地区：[1]中国地质大学(武汉)环境学院,武汉430074

出　　处：《环境工程学报》2012年第11期4006-4014,共9页Chinese Journal of Environmental Engineering

基　　金：国家"863"高技术研究发展计划项目(2007AA06Z333)

摘　　要：本文通过室内实验的方法,对山阴高砷地下水地区不同浅层沉积物中砷的分布特征及吸附行为进行了研究。结果表明:研究区内饮用水浓度高,病情重。浅层承压含水层中的砷含量平均值为290 mg/kg,在17.4～22.7 m段的平均值达643 mg/kg,22.7～25.8 m段的平均值为115 mg/kg,25.8 m以下的平均值为212 mg/kg。As(Ⅲ)、As(Ⅴ)在4种沉积物表面上的动力学吸附过程均符合Lagergren模型,相关系数达0.9以上。沉积物对As(Ⅴ)的吸附速率较As(Ⅲ)快,但As(Ⅲ)在沉积物中的吸附比As(Ⅴ)稳定。4种含水层介质对As(Ⅲ)、As(Ⅴ)的吸附速率依次为粘土>亚粘土>粉砂>中砂。吸附动力学吸附过程符合二级速率方程。Freundlich方程和Langmuir方程对As(Ⅲ)、As(Ⅴ)的吸附过程拟合性最佳,相关系数均在0.95以上。沉积物对As(Ⅲ)吸附的最佳pH在7～8范围内,As(Ⅴ)吸附的最佳pH在5～6左右。此外,沉积物对砷的吸附性能主要受沉积物颗粒大小、矿物成分等因素综合作用的影响,而非各组分吸附砷的简单加和。Different distribution characteristics and adsorption behavior of high arsenic groundwater on shallow sediments in Shanyin region,Shanxi Province,were studied.The results indicated that the concentration of arsenic in drinking water was high and the case prevalence was serious.The average content in shallow confined aquifer soil reached 290 mg/kg,while average value As concentration in the sediments of different segment of 17.4~22.7 m,22.7~25.8 m and 25.8 m below was 643 mg/kg,115 mg/kg,and 212 mg/kg,respectively.The adsorption dynamic processes of As（Ⅲ）,As（Ⅴ） on the four aquifer mediums（clay,subclay,silt,medium sand） could be fitted by the Lagergren kinetic model,with the correlation coefficient of 0.9.Compared As（Ⅴ） with As（Ⅲ）,the former adsorption rate was more faster,though the latter was more stable.The order of four different sediments on adsorption rate and capacity of arsenic was： clay loam silt mid sand.The results of experiments also showed the second-order rate equation had a better simulation for adsorption kinetic process.Both Langmuir and Freundlich isothermal equations could describe the thermodynamic behaviors of adsorption（R0.95）.The optimal pH range of As（Ⅲ） adsorption was 7 to 8,while pH 5 to 6 for As（Ⅴ）.In addition,sediment adsorption behavior of arsenic was mainly affected by the combination of sediment particle size,mineral composition and other factors,rather than the simple summation of each component.

关 键 词：沉积物 砷 吸附 PH 

分 类 号：X142[环境科学与工程—环境科学]