Bactericide adsorption by purple soil modified by decomposed liquid and humic substance from Bischofia javanica

To investigate the effect of plant decomposition products on bactericide adsorption, purple soil (P) was modified using different ratios of decomposed liquid (Dl) and humic substance (Hs) from Bischofia javanica. Isothermal adsorption characteristics of fenaminosulf and hymexazol by different Dl- and Hs-modified Ps (Dl-P and Hs–P) were studied using the batch method. The effects of pH, ionic strength, and temperature on bactericides adsorption were analyzed. The adsorption process of fenaminosulf and hymexazol on modified Ps was suitable to be described by the Freundlich model. Meanwhile, the adsorption capacity of two bactericides on Hs-Ps was higher than that on Dl-Ps. Acidic conditions and low temperatures were more favorable for the adsorption of fenaminosulf and hymexazol on modified Ps. The adsorption amount of fenaminosulf increased first and then decreased, but that of hymexazol decreased with the increase in ionic strength. The adsorption process of two bactericides was a spontaneous, exothermic entropy-increasing reaction, and the physical adsorption mechanism mainly controlled the adsorption rate. In conclusion, Dl-Ps and Hs-Ps showed potential environmental remediation applications.