Simultaneous photocatalytic treatment of wastewater containing uranium(VI) and tannic acid by ultrathin Bi2WO6/Bi2MoO6 heterojunction

In uranium(VI) (U(VI)) photoreduction, it is still a challenge to simultaneously degrade naturally coexisting organics and explore their impact on U(VI) photoreduction. Meanwhile, how to boost the separation and transport capability of photo-induced carriers is also a hot topic of current research. In this work, an ultrathin Bi 2 WO 6 /Bi 2 MoO 6 Z-type heterojunction was developed for the simultaneous treatment of U(VI) and its co-existing organics (tannic acid (TA)). Ultrathin interface engineering increased the contact area and shortened the transmission distance of photo-induced carriers. As a result, ultrathin Bi 2 WO 6 /Bi 2 MoO 6 exhibited highly efficient U(VI) removal rate (95.8 %) and TA degradation rate (97.2 %), which were much higher than those of bulk Bi 2 WO 6 /Bi 2 MoO 6 and single ultrathin Bi 2 WO 6 . In addition, the material possessed excellent stability and recyclability. Importantly, TA not only enhanced U(VI) removal by eliminating holes, but also favored U(VI) removal by serving as a bridge to the catalyst for U(VI) adsorption. Finally, a new mechanism was proposed.