Facile and large-scale fabrication of (Mg,Ni)(Fe,Al)2O4 heterogeneous photo-Fenton-like catalyst from saprolite laterite ore for effective removal of organic contaminants.

A facile and cost effective acid leaching-coprecipitation method was developed to prepare spinel-type (Mg,Ni)(Fe,Al)2O4 from saprolite laterite ore in large scale. The as-prepared (Mg,Ni)(Fe,Al)2O4 exhibited excellent photo-Fenton-like catalytic activity in decomposing different kinds of organic dyes and antibiotic tetracycline in the present of oxalic acid (H2C2O4). The influential factors of RhB degradation efficiency were investigated, including the (Mg,Ni)(Fe,Al)2O4 dosage, H2C2O4 concentration and the intensity of simulated sunlight. Meanwhile, the reaction mechanism of (Mg,Ni)(Fe,Al)2O4/H2C2O4/simulated sunlight system was also proposed. As the formation of highly photochemical [≡Fe(C2O4)3]3- complex ions on the surface of the (Mg,Ni)(Fe,Al)2O4, the obtained (Mg,Ni)(Fe,Al)2O4 showed degradation efficiency (η) over 90.0 % for common organic dyes and antibiotic tetracycline within 180 min under the optimum conditions. The η and TOC removal for RhB were still over 98.0 % and 46.0 % after five reuse cycles, respectively. The excellent catalytic performance and recyclability make the (Mg,Ni)(Fe,Al)2O4 fabricated from natural saprolite laterite ore more competitive in dealing with wastewaters contaminated by organic pollutants.