Batch Adsorption and Column Leaching Studies of Aniline in Chinese Loess Under Different Hydrochemical Conditions

Through batch adsorption and column leaching experiments, this study aimed to investigate the adsorption and transport behavior of aniline in loess and related mechanism under different hydrochemical conditions. Batch experiments results indicated that aniline adsorption reached equilibrium after about 120 min, and the adsorption fitted the pseudo-second-order kinetic and Freundlich models well. The adsorption was spontaneous and exothermic process, indicating the aniline adsorbed by inherent colloidal particles (ICPs) tended to transport. Low pH value, ionic strength and temperature benefitted the adsorption. Column experiments results under different ionic strengths (100, 10 and 1 mM) confirmed the potential transport of aniline. The FT-IR spectra have further suggested that aniline was adsorbed by the ICPs through hydrogen-bond, hydrophobic effect and cation exchange interactions. Low ionic strength was advantageous for the adsorption of aniline in loess and the stabilities of ICPs in solution, but enhanced the co-transport probability of ICPs with aniline in loess.