The study delves into the comprehensive exploration of ceria nanoparticle synthesis, explicitly focusing on distinct variants: fuel-rich, fuel-deficient, and stoichiometric proportions. These ceria variants are meticulously investigated using the sol-gel combustion method to uncover their unique characteristics. The exceptional performance of stoichiometric ceria is particularly notable, as it exhibits a well-defined crystal structure and balanced elemental composition. Conversely, fuel-deficient and fuel-rich ceria variants display altered lattice structures due to variations in their oxygen-to-cerium ratios. The study extends to the incorporation of these variants of ceria nanoparticles into PVDF polymeric membranes by flat sheet membrane synthesis for water application. The different ceria variant’s surface charges and electronic vacancies play a significant role in water purification and emulsion separation. Capitalizing on their individual properties, ceria-modified membranes are systematically evaluated, for membrane performance in terms of flux, recovery ratio and reusability. Stoichiometric ceria-incorporated membranes emerge as superior performers with 1.7x oil-water separation efficiency and reusability compared to pristine membranes. Therefore, ceria nanoparticle incorporated membrane can be used for sustainable environmental remediation of pollutants from the water.