Synergistic achievement of coexisted metal ion recovery and organics elimination in coupled photocatalysis-membrane distillation system

With the increasingly water pollution, treatment technologies for the pollutant removal, including metal ions and organics, have attracted wide attentions. Herein, we reported a coupled photocatalysis-membrane distillation reactor (PMR) based on BiOBr film for the simultaneous process of coexisted metal ion recovery (Ag + and Au 3+ ) and organics elimination (4-chlorophenol, 4-CP). The high efficiency of pollutant removal and water purification was successfully achieved. More importantly, Ag + and Au 3+ was photo-reduced into nanoparticles loaded on the surface of BiOBr film, and further enhanced the 4-CP photo-degradation. It could be found that Ag + ions greatly promoted the reduction of Au 3+ ions into Au nanoparticles, which further enhance the organics degradation. At the same time, Ag nanoparticles reduced from Ag + ions effectively consumed the photo-generated electrons to simultaneously improve the photocatalytic oxidation. This PMR system provided valuable insights for simultaneously achieving the elimination of organics and recovery of heavy metal ions from wastewater. • Coexisted metal ion recovery and organics elimination was simultaneously achieved on PMR. • High efficiency of pollutant removal and water purification was successfully achieved. • Au and Ag ions were photo-reduced on BiOBr film to enhance 4-CP photodegradation. • Ag nanoparticles promoted Au 3+ reduction and consumed photo-generated electrons.