Peng, Z; Gong, XY; Xiong, WF; Hu, HY; Ren, DJ
Organic acids affect the adsorption of organic pollutants in soil. To study the effects of fulvic acid and citric acid on the adsorp- tion of pyrene in soils with different organic matter contents and components, isothermal adsorption experiments were carried out. The re- sults showed that the adsorption Kd values of the original soil, a H2O2 treated soil (i.e., with soft carbon removed), and a burnt soil without organic matter decreased by 16.42%, 31.29%, and 30.47%, respectively, after adding citric acid, and by 79.09%, 47.77%, and 46.00%, re- spectively, after adding fulvic acid. When no acid was added, the adsorption Kd values of the H2O2 treated soil and burnt soil decreased by 73.35% and 88.21%, respectively, in comparison to the original soil. Citric acid and fulvic acid had dissimilar effects on the adsorption of pyrene in soil. Citric acid promoted the adsorption of pyrene in soil at low concentrations, but inhibited absorption at high concentrations. In contrast, fulvic acid at different concentrations inhibited pyrene adsorption, whereby an increased fulvic acid concentration enhanced the inhibition effect. In addition, the inhibition effect of fulvic acid was stronger for soils with a relatively high organic matter content and soils containing soft carbon components, whereas the inhibition effect of citric acid was stronger for soils with a relatively low organic matter con- tent and soils containing only hard carbon or minerals. © 2020 Editorial Board of Journal of Agro-Environment Science. All rights reserved.