摘要
紫色土中Cr(Ⅵ)的吸持量因土壤基本化学性质不同而存在较大的差异,游离铁及pH是影响最大吸持量的主要因子,“双表面”Langmuir模式最适宜于描述紫色土中Cr(Ⅵ)的吸持作用。酸性紫色土中,由于羟基交换、形成双核络合物等作用,吸持达到平衡的时间较长;中性及石灰性紫色土中,吸持作用在极短时间内即可达到平衡点。酸性紫色土中吸持Cr(Ⅵ)的解吸量及解吸率都比中性紫色土高。酸性紫色土在整个吸持区内都存在专性吸附,中性紫色土在低吸持区以非专性吸附为主,高吸持区伴有专性吸附。
A laboratory study on the reactions between Cr(Ⅵ) and purple soils was conducted to evaluate Cr(Ⅵ) retention and its mechanisms, Results from batch experiments and kinetic studies showed that Cr(Ⅵ)retained depended on chemical properties including free iron oxides and pH,Cr(Ⅵ)may possibly be retained specifically by free iron oxides; Two-surface' Langmuir described theretention the best among the models used, Cr(Ⅵ) released by water was adsorbed nonspecifically; Entropy change of Cr(Ⅵ) retention in acid purple soils was positive all over the concentration ranges, while in neutural purple soils it was negetive at low concentrations and positive at higher concentrations.
出处
《农业环境保护》
CSCD
1992年第1期11-16,共6页
Agro-Environmental Protection
