Utilization of Bi2WO6-encapsulated polyaniline-based redox reactions for the efficient detoxification of organic pollutants

Water contamination by toxic organic pollutants remains a serious public health problem for humans due to their long-lasting effects, so attention on specific methods and technologies to remove organic pollutants from waste water is desired. Numerous methods and photocatalysts are reported for the degradation of organic pollutants. In this work, BiVO4/Bi2WO6@polyaniline nanostructures were prepared successfully through facile wet chemical co-precipitation method and in sequence deposited over the BiVO4 surface for the first time. The surface morphology of synthesized photocatalysts was observed by scanning electron microscopy (SEM) and structural properties were investigated by X-ray diffraction (XRD). The addition of polyaniline and Bi2WO6 into BiVO4 shifted the characteristic peaks of BiVO4 towards lower 2 theta angle which is clear evidence of doping of these elements into BiVO4 structure under these conditions. In addition, the crystallite size of BiVO4 was also decreased due to incorporation of doping elements. Compared with pure BiVO4, hybrid photocatalysts exhibit higher photocatalytic activity and stability for degradation of phenol and ciprofloxacin under visible-light irradiation. When the effect of PANI in BiVO4-Bi2WO6 was examined, 1% PANI/BiVO4-Bi2WO6 heterojunction exhibited the highest photocatalytic performance. The degradation efficiency for phenol was 98% and 99% for ciprofloxacin at 90 min and this value was about seven times and three times higher than as compared to pure BiVO4 and BiVO4-Bi2WO6, respectively. The obviously improved photocatalytic performance of BiVO4-Bi2WO6/PANI composite was mainly ascribed to unique hierarchical structures, harvesting extended region of visible light, higher surface area, higher crystallinity, electronic transmission and narrow band gap, which significantly enriched the adsorption capacity and accordingly facilitated the separation of photogenerated charge carriers. The current findings may provide new insights into the employment of hybrid photocatalysts and improving the photocatalytic activity to address energy and environmental issues.