玉米芯生物炭对河岸带土壤中乙草胺和阿特拉津的吸附性能

Adsorption performance of corn cob biochar for acetochlor and atrazine in riparian soil

为改善农药对河岸带土壤污染状况,进而防控农业面源污染,以玉米芯为原料制备生物质炭,利用模拟实验研究其对河岸带土壤中乙草胺和阿特拉津的吸附性能影响,并探讨了其吸附机理。结果表明:河岸带土壤中添加生物炭可使乙草胺和阿特拉津的吸附容量显著增强,其吸附热力学过程与Freundlich和Langmuir模型拟合均有较好的相关性。与对照土壤相比,添加质量分数为1.0%生物炭的土壤对乙草胺的最大吸附量从13.28μg·g^(-1)升高到769.23μg·g^(-1);添加质量分数为0.3%生物炭的土壤对阿特拉津的最大吸附量从70.92μg·g^(-1)升高到333.33μg·g^(-1)。伪二级动力学速率方程对河岸带土壤吸附乙草胺和阿特拉津的过程拟合效果较好,优于一级动力学速率模型的拟合结果,吸附量以及吸附速率均与土壤中生物炭投加量成正比。玉米芯生物炭可作为河岸带土壤的修复剂,降低乙草胺和阿特拉津的迁移性。

In order to alleviate the pesticides pollution in riparian soil,and further prevent and control agricultural non-point source pollution,this study mainly focused on the adsorption behavior and mechanism of acetochlor and atrazine in riparian soil on a type of biochar derived from corn cob.Results show that the adsorption capacity of the riparian soil was remarkably enhanced by biochar addition.The adsorption thermodynamic process fitted well into both Freundlich and Langmuir models.In comparison with the control riparian soil,the maximum adsorption capacity of acetochlor on the biochar-amended soil increased from 13.28to 769.23μg·g^-1 at 1.0%weight biochar addition,and 0.3%weight biochar addition could cause the maximum adsorption capacity of atrazine to increase from 70.92to 333.33μg'g^-1.The fitting results of the adsorption kinetics of acetochlor and atrazine onto biochar-amended soil by the pseudo-second order kinetic model was better than the pseudo-first order kinetic one.Both the adsorption capacity and rate are proportional to the addition amount of biochar in the soil.Corncob biochar can be used as a remediation agent for riparian soil so as to reduce the migration of acetochlor and atrazine.