Dodecyltrimethylammonium chloride was used to modify na-bentonite in Sichuan Yanting. It was studied that the optimal modification conditions of bentonite and its optimum decoloration conditions of crystal violet in dyeing wastewater. The optimum preparation conditions were that the concentration of dodecyltrimethylammonium chloride was 1000mg /L, the preparation temperature was 70°C and the mixing time was 20 minutes. The optimum adsorption conditions for crystal violet were that the pH value was 8, the mixing time was 20 minutes and the dosing quantity of modified bentonite was 15 g/L. The decoloration rate was 85.4% under aforesaid conditions.
