The potential of removing Cr(Ⅵ), Ni(Ⅱ) and As(ⅡI) from aqueous solution by using mesoporous materials with MCM-41 functionalized with amine group, namely NH_2-MCM-41, was evaluated. Simplex-lattice design is studied in the multicomponent system with Cr(Ⅵ), Ni(Ⅱ) and As(ⅡI) adsorption onto NH_2-MCM-41. Triangular contour diagrams and triangular three-dimensional biosorption surface plots were generated to describe Cr(Ⅵ), Ni(Ⅱ) and As(ⅡI) adsorption equilibrium data in ternary system. The results showed that ...