E-waste based graphene oxide/V₂O₅/Pt ternary composite: Enhanced visible light driven photocatalyst for anti-microbial and anti-cancer activity

Microbial water pollution has gained increased attention due to its detrimental effects on humans and to the planet. Photocatalytic disinfection is reported as an efficient method for the treatment of microbial polluted waters. The current study evaluates the photocatalytic disinfection properties of graphene oxide/V₂O₅/Pt (GOV-Pt(1 %)) nanocomposite (alongside its anti-cancer activity) using Salmonella typhimurium as a model system. GOV-Pt(1 %) nanocomposite prepared in the study was confirmed by various characterization studies. Scanning electron micrograph confirmed the successful drafting of V₂O₅ onto graphene oxide sheet and Pt metal without any agglomeration. The optimum conditions for maximum disinfection were catalyst dosage of 100 mg/L, pH 3 and initial inoculum dosage of 6 Log₁₀ CFU/mL. Total organic carbon analysis confirmed the deterioration of bacterial cell wall leading to disinfection. In real effluents, a major decrease (98 %) in the total coliform colony forming units (CFU) was observed after disinfection. Sodium-oxalate was found to hinder the disinfection process to the maximum extent followed by Cr(VI), ethylene-diamine tetra acetic acid, isopropanol and H₂O₂. The results of MTT (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide) assay, cell staining assay, and apoptosis assay confirmed that the composite has anti-cancer activity but no cytotoxic activity.