Degradation of shale gas produced water by magnetic porous MFe2O4 (M = Cu, Ni, Co and Zn) heterogeneous catalyzed ozone

Abstract

Four magnetic spinel ferrite MFe2O4 (M = Co, Cu, Ni and Zn) were successfully prepared by the auto combustion reaction method and applied to catalyze ozone for treating the practical shale gas produced water (PW). This typical bio-refractory produced water was processed into a good biodegradability one. The catalytic performance of them was ranked as CuFe2O4 > NiFe2O4 > CoFe2O4 > ZnFe2O4. The B[Spsbackslash]C ratio was promoted from less than 0.1 to over 0.3, and the AOC concentration was improved 5 times, and AOC[Spsbackslash]TOC ratio could reach 8%. The bio-toxicity was decreased significantly which was evaluated by the EC50 of Photobacterium phosphoreum T3 and the growth inhibition ratio of E. coli, and it was decreased significantly. With the help of Scatchard model and Weber-Morris model, the results illustrated that the catalytic performance depended on surface property, and a suitable surface property could be an advantage in catalytic oxidation for degrading high concentration organic wastewater. The four MFe2O4 all presented a good recycling performance. This study provided a significant insight into the rational design and the advisable practice application of heterogeneous catalysts for dealing with shale gas produced water.