Visible light photodegradation of 2,4-dichlorophenol using nanostructured NaBiS: Kinetics, cytotoxicity, antimicrobial and electrochemical studies of the photocatalyst.

Removal of the hazardous and endocrine-disrupting 2,4-dichlorophenol (2,4-DCP) from water bodies is crucial to maintain the sanctity of the ecosystem. As a low bandgap material (1.37 eV), NaBiS was hydrothermally prepared and used as a potential photocatalyst to degrade 2,4-DCP under visible light irradiation. NaBiS appeared to be highly stable and remained structurally undeterred despite thermal variations. With a surface area of 6.69 m/g, NaBiS has enough surface-active sites to adsorb the reactive molecules and exhibit a significant photocatalytic activity. In alkaline pH, the adsorption of 2,4-DCP on NaBiS appeared to decrease whereas, the acidic and neutral environments favoured the degradation. An increase in the photocatalyst dosage enhanced the degradation efficiency from 81 to 86 %, because of higher vacant adsorbent sites and the electrostatic attraction between NaBiS and 2,4-DCP. The dominant scavengers degraded 2,4-DCP by forming a coordination bond between chlorine's lone pair of electrons and the vacant orbitals of bismuth, following the order hole> OH > singlet oxygen. Being non-toxic to both natural and aquatic systems, NaBiS exhibits antifungal properties at higher concentrations. Finally, the electron-rich NaBiS is an excellent electrocatalyst that effectively degrades organic pollutants and is a promising material for industrial and environmental applications.