Preparation of Core/Shell-Structured Znfe2o4@Znin2s4 Catalysts and its Ultrafast Microwave Catalytic Reduction Performance for Aqueous Cr(Vi)

Abstract

Irresponsibly discharge of hexavalent chromium (Cr(VI)) containing industrial wastewater has made the ecological environment in grave peril. In this work, a series of novel microwave (MW) responsive core/shell-structured ZnFe 2 O 4 @ZnIn 2 S 4 (ZFO@ZIS) catalysts were prepared for aqueous Cr(VI) reduction. The catalysts exhibited surprising MW catalytic activity, among which, FS3 catalyst (ZFO:ZIS=1:3) reached 100% Cr(VI) reduction efficiency within 15 min even the Cr(VI) concentration high up to 100 mg/L, which is superior to all currently reported photocatalytic catalysts. More significantly, the catalysts exhibited an excellent MW-reduction ability for Cr(VI) even at a pH value high up to 6, showing an excellent environment compatibility and a wide prospect in practical application. The excellent MW catalytic activity of the composite catalysts can be attributed to the MW induced "hot spots" effect. The MW responsive ZFO@ZIS core/shell-structured catalysts can be reasonably regarded as promising alternatives for high efficient reduction of Cr(VI) containing wastewater.

Keywords: Cr(VI) reduction, Microwave catalysis, Zinc ferrite, Indium zinc sulfide, Core/shell structure