Zinc oxide nanoparticles were developed by a facile green synthesis approach using plant extractions of Casuasina equisetfolia . The confirmative preparation and morphology of synthesized ZnO NPs are analyzed by the FTIR, XRD, SEM, DLS, and TEM technologies. FTIR confirms the preparation of ZnO NPs, and XRD, SEM, and TEM gave the surface structure and morphological information of ZnO NPs. ZnO NPs particle size was11-13 nm with amorphous nature having uniform distribution. Synthesized ZnO NPs were further applied as photocatalysts to degrade hazardous dye, Orange G, and gave a significant result. The adsorption behavior of ZnO NPs was also evaluated for Congored dye, which could effectively treat dye from an aqueous medium. The sorption results coordinate well with the Dubinin-Radushkevich isotherm (D-R) paradigm. The optimum monolayered sorption efficacy of ZnO NPs for CR was 42.01mgg -1 . Reaction kinetics obeyed the pseudo-second-order, and thermodynamics of sorption of CR onto ZnO NPs exhibited that the mechanism was endothermic and spontaneous. Therefore, the present study is economically and environmentally sound for water treatment.