The adsorption isotherms are evaluated at room temperature and in batch conditions. A mixture containing 4 mg of MT-CD@SiO2 composite and 1 mL of Cd2+ (ranging from 0.1 to 10 mg L1, pH 6.0) is shaken vigorously for 90 min. The cadmium concentration at equilibrium in the supernatant is quantified by GFAAS.