Facile synthesis of metal-doped magnesium ferrite from saprolite laterite as an effective heterogeneous Fenton-like catalyst

Metal-doped magnesium ferrite (MgFe2O4) with cubic spinel structure, large specific surface area and medium saturation magnetic strength was synthesized from saprolite laterite leaching solution through hydrothermal-calcination method and used as a heterogeneous Fenton-like catalyst. The influence of reaction temperature on the catalytic process was centrally discussed based on the hydroxyl radical theory. The as-prepared MgFe2O4 exhibited favorable catalytic activity for degradation of Rhodamine B (RhB), achieving 97.8% degradation efficiency of 10 mg.L-1 RhB within 300 min (90.0% degradation, 180 min) at the conditions of 45 degrees C, pH 6.44, 0.625 g.L-1 catalyst dosage and 1.00 vol% H2O2 concentration. And the TOC removal efficiency could reach 77.8%. After five consecutive degradation cycles, the reduction of degradation and TOC removal efficiencies were <3.0% and 8.0%, respectively, suggesting the metal-doped MgFe2O4 had high catalytic activity, good stability and excellent reusability. More importantly, the formed catalyst may broaden the application of saprolite laterite and provide a promising way for other natural minerals which contain transition metal elements in the treatment of organic dye wastewater. (C) 2018 Elsevier B.V. All rights reserved.