Adsorption of phenol on amphoteric-cationic modified Lou soil.

Using batch experiment,the adsorption of phenol on clay layer (CL) of Lou soil modified with a mixture of amphoteric modifier,dodecyl dimethyl betaine (BS-12),and cationic modifier,cetyltrimethylammonium bromide (CTMAB),were carried out,and its adsorption mechanism was discussed also. The adsorption capacity of phenol on CL of Lou soil could be enhanced significantly by complex modification. The phenol adsorption was ordered by CK(Unmodified soil) 50BS(50%BS-12)100BS(100%BS-12)50BS+25CT(50%BS-12+25%CTMAB)100BS+25CT (100%BS-12+25%CTMAB)50BS+50CT(50%BS-12+50%CTMAB)100BS+50CT(100%BS-12+50%CTMAB) at 20℃ and CK(Unmodified soil)50BS(50%BS–12) 100BS(100%BS-12) 50BS+25CT(50%BS-12+25%CTMAB) 50BS+ 50CT(50%BS-12+50%CTMAB)100BS+25CT(100%BS-12+25%CTMAB)100BS+50CT(100%BS-12+50%CTMAB) at 40℃. Henry equation was used to describe the phenol adsorption isotherm. The adsorption of phenol on the complex modified soil was a process with characteristics of both exothermic reaction and enthalpy decrease,its spontaneity being controlled by enthalpy decrease.