2种典型土壤中外源Ag^+的吸附行为及形态转化研究  

Adsorption Behavior and Speciation Transformation of Ag^+ in Phaeozem and Red Soil

作　　者：姚娜[1,2] 侯红[2] 王林权[1] 周友亚[2] 李发生[2] 

机构地区：[1]西北农林科技大学资源环境学院,杨凌712100 [2]中国环境科学研究院土壤污染与控制研究室,北京100012

出　　处：《环境科学》2010年第4期1085-1091,共7页Environmental Science

基　　金：科技部科技基础性工作专项项目(2007FY240200);中央级公益性科研院所基本科研业务专项(2007KYYW03)

摘　　要：采用一次平衡法研究了我国典型土壤——东北黑土和湖南红壤对Ag+的吸附特性及pH对土壤Ag+吸附的影响,并运用连续提取法分析了Ag+在2种土壤中吸附前后赋存形态的变化.结果表明,土壤对Ag+的吸附量随着Ag+溶液初始pH的升高而增加;在Ag+浓度为0～100mg·L-1范围内,东北黑土和湖南红壤对Ag+的吸附量均随着溶液中初始Ag+浓度的增加而增加,当Ag+浓度为0～20mg·L-1时增加明显,20～100mg·L-1趋于平缓.2种土壤的吸附等温线与Langmuir方程均具有良好的拟合性,拟合结果计算出Ag+在东北黑土和湖南红壤中的最大吸附量分别为250mg·kg-1和88.5mg·kg-1,表明东北黑土的吸附能力大于湖南红壤.东北黑土和湖南红壤的吸附动力学特征相似,吸附速率很快,均能在30min内达到吸附平衡,但东北黑土在0～30min内的吸附速率明显大于湖南红壤.形态分析结果表明,吸附后湖南红壤中离子交换态和残渣态的含量都增加迅速,而东北黑土中有机金属络合态、离子交换态、碳酸盐结合态和残渣态的含量增加明显.The batch equilibration experiments were carried out to study the adsorption characteristics of Ag^ ＋ and the effect of pH on the adsorption process in two typical Chinese soils,which the phaeozem from Northeast China and the red soil from Hunan province. The species transformation of Ag ^＋ was investigated in the experiments using the sequential extraction method. The results showed that an adsorption quantity of Ag ＋ for both soils increased with increasing solutions initial pH. Adsorption quantity of Ag ＋ in the two soils also increased with increasing of initial Ag ^＋ concentration in the range from 0 to 100 mg·L^-1,specifically,going up quickly in the concentration range of 0-20 mg·L^-1,but increased gently when Ag ＋ concentration exceeded 20 mg·L^-1 The Ag^ ＋ adsorption data of both soils were adequately described by Langmuir isotherm occurred in Ag^ ＋ sorption processes,their maximum adsorption quantities were 250 mg·kg ^-1 in the phaeozem soil and 88. 5 mg·kg ^-1 in the red soil,indicating a much higher adsorption capacity in northeast phaeozem soil than that of Hunan red soil. The two soils had similar adsorption kinetic characteristics,with respect to quickly reaching equilibrium within 30 minutes,but the adsorption rate of phaeozem soil was significantly greater than that of the red soil. The species analysis of Ag showed that exchangeable Ag and residual Ag increased in red soil,and metal-organic complex-bound Ag,exchangeable Ag,carbonate-bound Ag and residual Ag increased in phaeozem,respectively.

关 键 词：Ag+ 东北黑土 湖南红壤 吸附 化学形态 

分 类 号：X131.3[环境科学与工程—环境科学]