Zinc oxide photocatalyst electrogenerated from tea waste for the mitigation of chlorinated water pollutant in wastewater / Aunie Afifah Abdul Mutalib, Tasnim Aisya Mahmuelee Torlaema and Nur Farhana Jaafar

Zinc oxide is recognized for its effectiveness as a photocatalyst in pollutant degradation, but its conventional synthesis involves hazardous chemicals, posing significant limitations. This study introduces an eco-friendly ZnO electrosynthesis method using tea waste or tea leaf residues (TLR). The produced ZnO photocatalysts were analyzed using FTIR, SEM, XRD, and UV-DRS techniques and evaluated for their photocatalytic activity in degrading 2,4-dichlorophenol. Results indicated that the ZnO-TLR sample achieved a higher degradation rate of 2,4-dichlorophenol (90.5%) than commercial ZnO (62.1%). This superior performance of ZnO-TLR is attributed to its narrower band gap (3.20 eV), strong FTIR Zn-O bond signals, and uniform surface morphology. The phytochemical assay showed that the TLR extract had high phenolic contents, which likely contributed to these properties.