Sorption isotherm study of manganese removal from aqueous solutions by natural and MnO2-coated zeolite

The applicability of the natural and MnO2-coated zeolite as sorbent for the removal of Mn(II) from synthetic solutions has been investigated. Batch experiments were carried out to determine the influence of pH and Mn(II) concentration on the sorption process. A maximum removal efficiency (98.9%) was observed for modified zeolite with the concentration of 10 mg/dm3 of manganese in solution. The equilibrium data showed a very good correlation for both Langmuir and Freundlich sorption models and this suggests both monolayer adsorption and a heterogeneous surface existence. Maximum sorption capacity calculated from the Langmuir model constituted 5.57 mg/g for natural zeolite and 13.41 mg/g for modified zeolite.