磺胺嘧啶在黑土及其不同粒径组分中的吸附行为研究

采用批平衡吸附试验法,研究了磺胺嘧啶在黑土及其不同粒径中的吸附行为。结果表明,磺胺嘧啶的吸附不同程度地偏离线性模型,但均可用Freundlich模型和Langmuir模型进行良好地线性拟合。黑土（〈0.2mm）及其不同粒径（粘粒：〈0.002mm、粉粒：0.002~0.02mm、砂粒：0.02~0.2mm）的Freundlich容量因子Kf值分别为29.6、53.1、32.9L.kg-1和21.6L.kg-1,说明磺胺嘧啶在黑土及其不同粒径中的吸附行为存在差异。将吸附参数Kf进行碳标化处理后,Koc值除粉粒外,其他基本一致。随着溶液pH的持续增加（1.0~10.0）,黑土及其不同粒径中的磺胺嘧啶的吸附参数lgKf呈现先急剧降低然后稍微回升的趋势,由此推测,阳离子交换作用可能是磺胺嘧啶土壤吸附的重要机制。过氧化氢处理去除土壤有机质后,黑土的Kd值从1.92L.kg-1降为1.22L.kg-1,磺胺嘧啶的吸附量由16.5mg.kg-1降低到11.2mg.kg-1,说明有机质含量也是影响磺胺嘧啶吸附行为的重要因素。

Adsorption Behavior of Sulfadiazine on Black Soil and Its Different Particle Sizes

The adsorption of sulfadiazine on the black soil and its different particle sizes was tested by batch equilibrium experiments.The results showed that the adsorption data were well fitted for the Freundlich and Langmuir model,but deviated different degrees from the linear model.The Freundlich model parameter Kf values of the bulk soil（0.2 mm） and different particle sizes（clay：0.002 mm,fine：0.002~0.02 mm,sand：0.02~0.2 mm） were 29.6,53.1,32.9 L·kg-1 and 21.6 L·kg-1,respectively,which showed that there was some difference in the sorption behaviors of sulfadiazine in different soil sizes.After treated with organic carbon normalized equation on the Kf,the resulting Koc values showed some consistentance except for the silt particle.With the increase of the solution pH（1.0~10.0）,the lgKf values of sulfadiazine presented a trend that greatly decreased and then slightly increased.It could be deduced that the cation exchange might be the predominant sorption mechanism of sulfadiazine on the tested soils.After dealt with H2O2,the Kd value of the bulk soil decreased from 1.92 L·kg-1 to 1.22 L·kg-1,and the sorption amount of sulfadiazine decreased from 16.5 mg·kg-1 to 11.2 mg·kg-1.It suggested that organic matter amount was also an important factor which affected the sorption of sulfadiazine on soils.