Zinc doped BiOBr impregnated into PVDF sponge as a dipPhotocatalyst for RhB removal from wastewater

Abstract

Organic contamination of water has sparked concerns since it has an adverse impact on both human health and the ecosystem as a whole. In this study, Bismuth Oxybromide (BiOBr) was prepared via a Solvothermal approach. Subsequently, BiOBr was doped with Zinc metal to improve the photocatalytic activity through introduce Oxygen vacancies (OVs). The as-prepared materials were characterized using various techniques; Field-Emission scanning electron microscopy (FE-SEM) & Energy dispersive X-ray (EDAX) and elemental composition analysis, X-Ray diffraction (XRD), FTIR spectroscopy and X-ray Photoelectron spectroscopy (XPS). Additionally, optical features (Optical Absorption, band gab, and PL Spectroscopy) and electrochemical impedance spectroscopy (EIS) were also evaluated. The FE-SEM confirmed that, the formation of BiOBr and Zn-BiOBr in a hierarchical microspheres structure constructed from nano-leaves. The physico-chemical characterizations confirm the generation of OVs upon doping with zinc, the optical features results showed a slight increase in optical band gab of BiOBr (2.811 eV) upon doping with Zinc (2.831 eV) while, the PL of BiOBr is higher than that of Zn-BiBOr and EIS results confirms the lower resistance of charge transfer of Zn-BiBOr indicating electron–hole separation leading to improvement and enhancement RhB’s degradation efficiency, with achieving 100% removal after 35 min of reaction. However, the challenge of photocatalyst (as a suspension) separation after the degradation reaction remained. To resolve this issue, we developed a simple technique to impregnate Zn-BiOBr into a highly porous sponge based on Polyvinylidene Fluoride polymer (PVDF) as a dip-photocatalyst, offering potential as a re-usable photocatalyst matrix. Furthermore, the 3D Zn-BiOBr photocatalyst sponge was tested and Found to sustain up to five cycles in consecutive cycles with almost the same photocatalytic effectiveness. In conclusion, the PVDF − Zn-BiOBr sponge is a promising material for energy conversion applications and environmental purposes and enables the reuse of the photocatalyst several times easily.