All chemicals were analytical grade and used without further purification. Kaolin, provided by Shanghai Reagent Co., China, is composed of Al4[Si4O10][OH]8 [surface area: 20 m2 g−1 and pore volume: 0.5 cm3 g−1]. 0.3 g L−1 synthetical MB represented dye wastewater used in the experiment. NaOH or H2SO4 in proper amounts was used to get the suitable original pH value.