Adsorption and Coprecipitation of As(V) from Aqueous Solutions by Manganese Dioxide

The effects of solution pH and initial concentration on adsorption and coprecipitation of As(V) from aqueous solutions by manganese dioxide [MnO(2)] for 50d and 1120d were studied. The XRD, FT-IR and SEM results indicated that there was only slight difference between the MnO(2) adsorbents before and after adsorption, but their crystal structure had not changed. For the initial As(V) concentration C(o)=0.1 or 1.0 mmol/L, the adsorption efficiency of As(V) onto MnO(2) decreased with the increasing pH when pH from 2.0 to 12.0. For the initial As(V) concentration C(o)=0.01 mmol/L, the adsorption efficiency exceeded 95% at pH 2-8 after 50d or 1120d reaction, but the As(V) concentration in the solution after adsorption for 1120d was higher than that for 50d.