Valappil, R.S.K.Vijayanandan, A.S.Mohan Balakrishnan, R.M.2026-02-082020Sustainable Eco-technologies for Water and Wastewater Treatment, 2020, Vol., , p. 59-7097817890613769781789061369https://doi.org/10.1117/1.JRS.19.048503https://idr.nitk.ac.in/handle/123456789/33776In this work, the photocatalytic activity of the biosynthesized cobalt oxide (Co3O4) nanoparticle (NP) is investigated using a textile dye Reactive Blue 220 (RB220) and decolorization % was monitored using UV–Vis spectrophotometer. The photocatalytic activity has been observed maximum at alkaline pH of 9, NP dosage of 250 mg/L, and reaction time of 270 min. In the presence of UV light irradiation, a maximum dye concentration of 10 mg/L was treated effectively using 150 mg/L NP, and 67% decolorization was achieved. Reaction kinetics has been analyzed, and the reaction followed the pseudo kinetics model with an activation energy of 484 kJ mol1. © 2020 IWA Publishing.Co3O4 nanoparticlesDecolorizationKineticsPhotocatalysisRB220