ZnSe-WO3 nano-hetero-assembly stacked on Gum ghatti for photo-degradative removal of Bisphenol A: Symbiose of adsorption and photocatalysis

Abstract

In this research work we report Gum-ghatti supported ZnSe-WO3 nano-hetero-assembly for solar powered degradation of endocrine disruptor Bisphenol S (BPA). The photocatalyst was characterized by Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), Small area electron diffraction (SAED), X-Ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), Photoluminescence (PL), Energy dispersive X-ray (EDX), UV–vis spectrophotometry and Brauner Emmet Teller surface area analyzer (BET). We achieve a Z-scheme photocatalyst (ZnSe-WO3) with a higher charge flow and visible absorption. Gum ghatti acts as a superadsorbent and a sink for charge carriers. The removal of BPA has been studied under three experimental protocols where 99.5% removal was achieved by symbiose of photocatalysis-adsorption-ozonation in just 45min hetero-assembly has a high surface area, stability and reduced carrier recombination. The results have been analyzed by scavenger effect, mass spectrometry, kinetics and total organic carbon (TOC) analysis. 49.4% of TOC was removed and COD was reduced to 16.7% after 2h in symbiotic condition. From the band edges and scavenger effect it was inferred that superoxide radical anions are major attacking species. The work paves way for designing of novel photocatalysts with increasing biogenic quotient and higher efficiency.