Abstract:The sorption mechanism of reversible cationic surfactant (11-ferrocenylundecyl) trimethylammonium bromide (FTMA) on bentonite was studied, and compared with CTAB; the effects of the key factors of soil on sorption were also studied. Results show that, sorption variation of FTMA is consistent with CTAB, the saturated sorption capacity of FTMA is 66cmol/kg, about one times CEC of bentonite, it suggests that cation exchange is the main sorption mechanism. The isotherms of FTMA all can be described with Langmuir model at different temperature, and the sorption capacity increases from about 280.6mg/g at 298K to about 350.8mg/g at 318K. The sorption of FTMA reaches equilibrium at 8h, the sorption rate is slower than CTAB, and fits Lagergren quasi-second-order kinetics equation, chemical sorption process is the main step of controlling rate. The sorption process is spontaneous and endothermic through thermodynamic parameters calculated. In addition, sorption capacity of FTMA decreases with ionic strength increasing; the sorption is inhibited by coexisting cations, and following order: Ca2+>K+>Na+; the impact of pH is slight and the addition of humic acid (HA) promotes the sorption of FTMA.