不同添加剂对土壤中乙草胺吸附/解吸的影响

Impact of Different Addtives on the Sorption and Desorption Behavior of Acetochlor in Soil

采用批处理恒温振荡法,利用气相色谱-质谱联用仪研究了人工添加不同吸附物质对土壤中乙草胺的吸附/解吸作用。结果表明,人工添加不同吸附物质对土壤中乙草胺的吸附强度和吸附容量不同,不同的添加剂对土壤中乙草胺的吸附/解吸作用均呈现明显的非线性关系,可用Freundlich模型描述。并且随着土壤中添加剂量的增大,吸附强度增大、吸附容量增大、所得吸附等温线的非线性也逐步增大;另外,添加剂对乙草胺的解吸迟滞作用也随添加剂含量的增高而更加明显。但是不同添加剂对土壤中乙草胺的吸附能力有明显差异,其中煤粉的吸附能力最大,其次是壳聚糖,沸石最小。

Acetochlor is the biggest area herbicides application in China. Because of the drought condition of soil, high dosage of acetochlor is used for enhancing the effective control weed in crop. Sometimes the crops are damaged and soils are polluted by herbicide. Sorption of acetochlor in soil is influenced by soil environment, and the additive can obviously adsorb the herbicide of soil, then ease the harming from the herbicide and the pollution of soil environment. This paper researched adsorption and desorption to the acetochlor with appending different adsorbent artificially by the method of utilizing gas chromatograph-mass spectrometer in the soil, providing the theories a basis of comprehensive manage for the herbicide pollution. The experimental result showed that the adsorption strength and the adsorption capacity to the acetochlor in the soil differed with different additives, and all the sorption and desorption isotherms of the acetochlor in the soil by appending different additives were nonlinear, which could be described with Freundlich model. The adsorption strength, the adsorption capacity, and the non-linearity of the adsorption isotherm were all increasing gradually with the thickening of the appending concentration, also the desorption hysteresis of the additives to the acetochlor was more apparent with the increase of the additives content. However, the adsorption capacity of different additives to the acetochlor in the soil varied apparently, wherein, the pulverized coal had the greatest adsorption capacity, the chitosan had less, and the zeolite had the least.