Enhanced visible-light photocatalytic performance by PPy/CN composites for reduction of UO22+

Efficient elimination of U(VI) from uranium wastewater is one of the most urgent tasks for sustainable nuclear energy, ecosystem protection and public health. A simple wet-chemical method was used to prepare polypyrrole (PPy) modified carbon nitride (CN) for the removal and recovery of uranium from wastewater. Compared with the traditional carbon nitride, a stronger interaction appeared between PPy and CN which facilitated the separation and transport of photogenerated carriers, and decreased the band gap which was beneficial to visible-light absorption. The visible-light-driven photocatalytic reduction reactions of U(VI) were carried out to test the catalytic activity of composite materials. The optimum photocatalytic performance was achieved on 20% PPy/CN, which was more than twice higher than that of CN. The composite also displayed excellent stability, which still kept above 95% reduction efficiency after five consecutive cycles. The results acquired may shed light on photocatalytic reduction of uranium strategies for designing potentially efficient photocatalysts.