Cu/Cu2O/NH2-MIL-88B (Fe) heterojunction as the photocatalyst to remove hexavalent chromium heavy metal ions in water

Abstract

This work aimed at addressing the problem of hexavalent chromium pollution in the water environment, designing and preparing the Cu/Cu₂O/NH₂-MIL-88B (Fe) heterojunction material with NH₂-MIL-88B (Fe) as the carrier, Cu/Cu₂O was loaded on NH₂-MIL-88B (Fe) by light-assisted reduction. The loading of Cu₂O effectively improves the visible light absorption capacity of the composite material. The SPR effect of Cu improves the separation and transfer of photogenerated carriers in the composite material. Performance test results showed that under the condition of pH = 2, using ethanol as a sacrificial agent, Cu/Cu₂O/NH₂-MIL-88B (Fe) (15 wt%) had a photocatalytic adsorption reduction rate of Cr(VI) of 96.3% in 60 minutes of adsorption in the dark and 150 minutes of photocatalytic reduction, which was 1.39 times that of NH₂-MIL-88B (Fe). In addition, the composite material had good stability and recyclability, and the reduction efficiency still reached 88.9% after three cycles.