Adsorption of phenanthrene on amphoteric-cationic modified yellow-brown soil

LIU Wei;LI Wen-bin;MENG Zhao-fu;HANG Zhao-xi;WANG Teng;HU Xiao-long;REN Shuang;Department of Natural Resource and Environment, Northwest A&F University;Department of Chemical and Environmental Engineering, Xinjiang Institute of Engineering;College of Environmental Science and Engineering,China West Normal University;Key Laboratory of Plant Nutrition and Agri-Environment in Northwest China,Ministry of Agriculture;

combined modification;;yellow-brown soil;;phenol;;phenanthrene;;adsorption capacity

Two series of amphoteric-cationic modified yellow-brown soils, containing 43% and 6% montmorillonite, were used to explore the adsorption effect and mechanism of phenanthrene on co-modified yellow-brown soils. The experiment was based on the best modification ratio of adsorption of phenol on montmorillonite modified by an amphoteric modifier of dodecyl dimethyl betaine(BS-12) and a cationic modifier of hexadecyltrimethyl ammonium bromide(CTMAB). The adsorption properties of phenanthrene at different temperature, pH, and ionic strength were analyzed. The related adsorption mechanism was also explored. Results showed that adsorption of phenanthrene on comodified yellow-brown soils increased as the total modification ratios increased. The Henry model successfully described the adsorption of phenanthrene. Adsorption of phenanthrene on modified yellow-brown soils decreased as temperature and pH increased, but increased as ionic strength increased at low concentration ranges. Distribution played a leading role in the adsorption of phenanthrene on co-modified yellow-brown soils. In general, the mechanism of phenanthrene adsorption on modified yellow-brown soils was similar to that of phenol.Overall, cation exchange capacity(CEC)and modification ratios were the most important factors influencing the adsorption of phenanthrene on co-modified yellow-brown soils.