Study on Adsorption Behaviors of As(Ⅲ) by Manganese Oxide, Iron Oxide and Aluminium Oxide

Three minerals of manganese oxide, iron oxide and aluminium oxide were synthesized and the effects of pH value and ionic strength of the solution, adsorption equilibrium time on adsorption of As(Ⅲ) by manganese oxide and iron oxide were studied. And the saturated adsorption capacity and the isothermal adsorption of As(Ⅲ) by three minerals were also tested. The results showed that pH value had less influence on adsorption of As(Ⅲ) by manganese oxide and less influence on adsorption of As(Ⅲ) by iron oxide in pH range of 3.5～8.5. The results also showed that ionic strength had less effect on adsorption of As(Ⅲ) by iron oxide and manganese oxide. The adsorption equilibrium time was about half an hour. The order of the saturated adsorption capacity of As(Ⅲ) by three minerals was: manganese oxide>iron oxide>aluminium oxide with saturated adsorption capacities of 48.38 mg/g, 23.70 mg/g and 3.52 mg/g respectively under the optimized adsorption condition. The adsorption data were fitted by both Freundlich and Langmuir isotherm models with correlation coefficient of R>0.98 and adsorption kinetic data correlated well with Lagergren second kinetic equation.