青霉素钠在土壤中的吸附和淋溶特性

摘要

Adsorption and leaching of sodium penicillin in soils and their affecting factors were studied with the vibrating equilibrium method and the column leaching method. Results show that adsorptions of the substance in red soil from Jian⁃gxi, paddy soil from Taihu and black soil from Northeast China at 25℃ or below,were fairly well fitted with the Freundlic model with adsorption constant being 30�73, 39�26 and 64�58 mL·g-1 , respectively. PLS ( partial least squares) analy⁃sis reveals that soil clay and organic matter were the key factors affecting soil adsorption of sodium penicillin in the soils. Free energies of sodium penicillin adsorption in all the three soils were less than 40 kJ·mol-1 , suggesting that the adsorp⁃tion belonged to the type of physical adsorption. The soils followed an order of Northeast China black soil > Taihu region paddy soil > Jiangxi red soil in terms of sodium penicillin adsorption capacity. The leaching experiment indicates that the content of soil clay and the content of organic matter are also the two factors affecting leaching of sodium penicillin in soils, and that the three soils followed an order of Jiangxi red soil>Taihu region paddy soil>Northeast China black soil in terms of sodium penicillin movability in the soil profiles.%分别采用振荡平衡法和土柱淋溶法分析了青霉素钠在不同土壤中的吸附和淋溶特性及其影响因素。结果表明，25℃以下，3种供试土壤对青霉素钠的吸附特性能用Freundlic模型进行较好的拟合，江西红壤、太湖水稻土和东北黑土的吸附常数KF 分别为30�73、39�26和64�58 mL·g－1。偏最小二乘法（ PLS）分析表明土壤黏粒含量和有机质含量是影响土壤吸附青霉素钠的主要因素。供试土壤对青霉素钠的吸附自由能变化值均＜40 kJ · mol－1，该吸附过程主要属于物理吸附，吸附能力由大到小依次为东北黑土、太湖水稻土和江西红壤。土柱淋溶试验结果显示，土壤有机质含量和黏粒含量亦是影响淋溶过程的主要因素，青霉素钠在土壤剖面中的迁移能力较弱，3种土壤淋溶性能由大到小依次为江西红壤、太湖水稻土和东北黑土。