Removal of Cd2+ by Synthetic nano-Cryptomelane from Sewage

Abstract:

Removal rates of Cd2+ from sewage prepared in laboratory by synthetic nano-Cryptomelane under several factors were measured. The effluence of each factor on the rates was studied. The results showed that it took 2h before the removal process reached balance; when the concentration of Cd2+ was 50 mg•L-1, pH=6.50, 2 g•L-1 of the adsorbent dosage, 2 h of the adsorption time, the removal rate of Cd2+ was 90.6%. The adsorption isotherm was fitted by Langmuir model, and the theoretical maximum adsorption capacity was 120.5 mg•g-1 when the concentration of Cd2+ was less than 300 mg•L-1. The mechanisms of surface coordinate reactions, surface electrostatic adherences and ion exchanges are co-existing to remove Cd2+ from the solution treated by the synthetic nano-Cryptomelane.