[Application of Amphoteric-Cationic Combined Modification on Phenol Adsorption of Yellow Brown Soil]

Based on the best modification ration of adsorption of phenol on montmorillonite modified by a mixture of amphoteric modifier, dodecyl dimethyl betaine(BS-12), and cationic modifier, hexadecyltrimethyl ammonium bromide(CTMAB),an experiment was designed to prepare two series of amphoteric-cationic modified soils by two yellow brown soils with montmorillonite contents of 43% and 6%,respectively. The adsorption properties of phenol were studied, and the adsorption influence at different temperature, pH and ionic strength was also analyzed and moreover, the adsorption differences between co-modified montmorillonite and yellow brown soils and between two co-modified yellow brown soils were discussed by comparing with co-modified montmorillonite. The results showed that adsorption of yellow brown soils as well as co-modified montmorillonite on phenol increased with combined modification, adsorption capacity was in order of 215BS+215CT(215%BS-12+215%CTMAB) > 215CT(215%CTMAB) > 215BS(215%BS-12) > CK1(unmodified soil containing montmorillonite content of 43%),33BS+33CT(33%BS-12+33%CTMAB) > 33CT(33%CTMAB) > 33BS(33%BS-12) > CK2(unmodified soil with montmorillonite content of 6%) at 30℃.Henry model described the adsorption of phenol very well. The phenol adsorption of modified yellow brown soils decreased with increasing temperature and pH, but increased with increasing ionic strength at low concentration ranges as well as modified montmorillonite. The basic reason for adsorption difference between co-modified montmorillonite and yellow brown soils and between two co-modified yellow brown soils was Cation Exchange Capacity(CEC).