几种农药对土壤中铬吸附行为的影响

Pesticides Influence on the Chromium Adsorption of Paddy Soil

通过等温吸附实验,分别研究了仲丁威、三唑磷、马.异乳油、硫.三环唑和2,4-D等5种农药对土壤中Cr(Ⅲ)和Cr(Ⅵ)吸附行为的影响.结果表明,对照组和5种受试农药影响下,土壤对Cr(Ⅲ)和Cr(Ⅵ)的吸附等温线均符合Freundlich和Langmuir方程.5种受试农药对Cr(Ⅲ)的吸附率和饱和吸附量的影响较小.但马.异乳油和硫.三环唑使土壤吸附Cr(Ⅲ)的亲和力常数k和标准自由能变ΔG0下降,表明它们降低了土壤对Cr(Ⅲ)吸附强度.此外,三唑磷和硫.三环唑降低了土壤对Cr(Ⅵ)吸附,饱和吸附量较对照分别减少了11.0%和9.8%,而马.异乳油能显著地增加土壤对Cr(Ⅵ)的吸附,使饱和吸附量增加36.4%.

Five pesticides influence（ fenobucarb, triazophos, malathion ＋ isoprocarb, sulfur ＋ tricyclazole and 2, 4-D） on the isotherm adsorption of Cr （Ⅲ ） and Cr （Ⅵ） on paddy soil is studied in batch equilibrium experi- ments. The results indicate that the isotherms of Cr （ Ⅲ ） and Cr （Ⅵ） can be represented by Freundlich and Langmuir equations. The five pesticides on the adsorption ratio and maximum adsorption of Cr（ Ⅲ ） are not obvious. However,the affinity constant and standard free energy chhnge of Cr（ Ⅲ ） and Cr（Ⅵ） adsorption on soil are decreased by malathion ＋ isoprocarb and sulfur ＋ tricyclazole,indicating the decrease of adsorption strength. Triazophos and sulfur ＋ tricyclazole can reduce the adsorption maxima of Cr（Ⅵ） on soil by 11.0% and 9. 8%. Moreover,the adsorption of Cr（Ⅵ） of soil can be increased by malathion ＋ isoprocarb which increases the maximum adsorption by 36.4% .