This review article comprehensively discusses the recent development of various environmental applications of Zinc Oxide (ZnO) semiconductor materials. The synthesis of various nano/micro structured ZnO using different methods and the influence of various preparation conditions on ZnO morphology are discussed. The environmental applications of nano/micro structured zinc oxide as an adsorbent, photocatalyst, and catalyst in catalytic ozonation processes are discussed. The adsorption of various organic pollutants and metal ions on the ZnO surface at different conditions are discussed. The ZnO assisted photocatalytic degradation of pollutants, water splitting, and disinfection under various conditions are reported on. Ozonation in the presence of zinc oxide and its influence on the removal of pollutants are also included.