土壤中铬的化学行为研究Ⅴ．土壤对Cr（Ⅲ）吸附和沉淀作用的影响因素  

STUDY ON CHEMICAL BEHAVIOR OFCHROMIUM IN SOILSV. FACTORS AFFECTING Cr(III) ADIJSORPTION ANDPRECIPITATION IN SOILS

作　　者：陈英旭[1] 骆永明[1] 朱永官[1] 朱祖祥[1] 何增耀[1] 

机构地区：[1]浙江农业大学,中科院南京土壤研究所

出　　处：《土壤学报》1994年第1期77-85,共9页Acta Pedologica Sinica

摘　　要：本试验研究了土壤、矿物对Ｃｒ（Ⅲ）的吸附和沉淀作用，结果表明：在ｐＨ４．０时，三种土壤对Ｃｒ（Ⅲ）的吸附量是青紫泥＞黄筋泥＞旱地红镶。Ｃｒ（Ⅲ）的吸附量和沉淀量之和随ｐＨ的变化曲线可分为四个区域。在Ｃｒ（Ⅲ）吸附或吸附一沉淀区域的ｐＨ范围内（ｐＨ＜６．０），土壤对Ｃｒ（Ⅲ）的吸附分量随溶液中ｐＨ升高而减少，沉淀分量则随ｐＨ升高而增加；溶液中富啡酸和柠檬酸的存在可以增加Ｃｒ（Ⅲ）的沉淀量。r(III) removal in solutions with different pH values was measured under con-ditions of adding and without adding soils and minerals. With pH increasing insoil solution, the amounts of Cr(III) removal by adsorption and precipitation incre-ased when pH < 10.5, but decreased when PH > 10.5. The curve of Cr(III) removalby soils and minerals could be divided into four ranges: (1) pH range of Cr(III)adsorption when pH < about 4.0, (2) pH range of Cr(III) adsorption-precipitationwhen pH 4-6, (3) pH range of Cr(III) stable precipitation when pH 6-10.5, and(4) pH range ol Cr(III) hydrolysis when PH > 10.5.Organic acids such as citric acid and fulvic acid existing in soils would raiseCr(III) dissolubility and stability in pH range of 4-7. The pH value causing pre-cipitation of fulvic acid-Cr(III) was about pH 7.0 and rose by 3 pH unites comparedwith that of Cr(III) precipitation. Whereas, little effect on Cr(III) dissolubility wasfound for humic acid existing in soil solution. The existence of phosphate in sol-ution would lower the PH value causing stable precipitation of Cr(III).The amounts of Cr(III) adsorbed by three soils at pH 4.0 followed the sequ-ence: stagnogleyed paddy soil > submergic paddy soil from red soil > upland redsoil.Cr(III) adsorption isotherms fit Langmuir and Freundlich equations in theniontmorillonite-Cr(III) system, but did not fit Langmuir and Freundlich equationsin the soil-Cr(III) system.

关 键 词：铬 土壤 吸附作用 沉淀作用 

分 类 号：S153.61[农业科学—土壤学]