Construction of Fe2O3/Co3O4/exfoliated graphite composite and its high efficient treatment of landfill leachate by activation of potassium persulfate

Abstract

Landfill leachate, as one of high-ammonia nitrogen organic pollutants, has been characterized to be potentially dangerous on ground water and soil. However, traditional technologies cannot deal with these substances swiftly. Thus, in this study, exfoliated graphite (EG) immobilized ferric oxide and cobaltosic oxide species has been successfully constructed by a facile heating-precipitation strategy. Subsequently, physicochemical properties of Fe2O3/Co3O4/EG were investigated by scanning electron microscope, X-ray diffraction, N2 adsorption/desorption, X-ray photoelectron spectroscopy measurements. Results indicated that Fe2O3 and Co3O4 nano-particles were successfully deposited onto the surface and interstice of EG substrate. In addition, activation performance of Fe2O3/Co3O4/EG composite was evaluated by activating potassium persulfate (PS) to degrade the landfill leachate. In addition, effect of some critical operating parameters on the removal of landfill leachate was studied systematically. The experimental results showed that 90.6% of NH4+-N and 67.1% of COD in landfill leachate could be removed at the optimized conditions of pH 5, PS concentration 0.05 M and Fe2O3/Co3O4/EG dosage 0.1 g. Furthermore, Fe2O3/Co3O4/EG sample also displayed good recycle and reusable capacities. Besides these, high-efficient removal mechanism of Fe2O3/Co3O4/EG was proposed. This study provides a feasible strategy to prepare catalyst which could be potentially applied in refractory contaminants elimination.