Kadam, V.V.Shanmugam, S.D.JagadeeshBabu, J.Mohan Balakrishnan, R.M.2026-02-052021Environmental Science and Pollution Research, 2021, 28, 10, pp. 12119-121309441344https://doi.org/10.1007/s11356-020-10833-whttps://idr.nitk.ac.in/handle/123456789/23338The present work deals with the photocatalytic degradation of p-nitrophenol as it is a United States Environmental Protection Agency-listed priority pollutant and has adverse environmental and health effects. To eradicate the detrimental environmental impact of p-nitrophenol, the biologically synthesized ZnO nanoparticles were used as a photocatalyst. The degradation of p-nitrophenol was confirmed by decreasing the absorbance value at a characteristic wavelength of 317 nm using the UV-vis spectrophotometer. Reaction parameters such as ZnO photocatalyst concentration of 0.1 g/L at pH 11 in the presence of H<inf>2</inf>O<inf>2</inf> (5 mM) were found to be optimum conditions for p-nitrophenol degradation. The photocatalytic degradation was slowly enhanced in the presence of H<inf>2</inf>O<inf>2</inf> as an electron acceptor. The kinetics of nitrophenol degradation was studied, which follows the pseudo-first-order reaction. The photocatalytic degradation of p-nitrophenol was characterized by using total organic carbon, chemical oxygen demand, and high-performance liquid chromatography analyses. This method is found to be effective as it is environmentally friendly, free of toxic chemicals. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.absorbancechemical oxygen demandnanoparticleorganic compoundphotodegradationreaction kineticstotal organic carbonzinc4-nitrophenolhydrogen peroxidenitrophenolzinc oxidecatalysisCatalysisHydrogen PeroxideNitrophenolsZinc Oxide