Poly(vinylidene fluoride)/Nickel Oxide–Montmorillonite Mixed-Matrix Membranes for Oil Separation from Emulsified Oily Wastewater

Microemulsions originating from food industries, textiles, paint industries, kitchen wastes, and oil spills on roads ultimately form a complex cocktail of emulsified water sources that are difficult to separate. Traditional methods often fail to provide stable and efficient separation of these microemulsions at the tertiary stage, highlighting the need for advanced membrane technologies. This study explores the incorporation of nickel oxide and montmorillonite (NiO-MMT) nanoparticles into poly(vinylidene fluoride) (PVDF) membranes to enhance the separation of microemulsified oil from water. By integrating 2% NiO-MMT, the membrane surface becomes significantly smoother compared to pristine PVDF membranes, thereby enhancing its antifouling properties. The addition of NiO-MMT significantly improves the hydrophilicity of the membrane matrix, resulting in a pure water permeance of up to 3781 ± 3% L·m –2 ·h –1 ·bar –1 . Experimental results indicate that NiO-MMT-incorporated PVDF membranes exhibit a >5.3 times increase in motor oil–water separation efficiency and a 1.4 times increase in the separation efficiency of both palm oil and mustard oil from water compared to pristine membranes. The hydrophilic nature and high surface energy of the composite membrane effectively separates stable microemulsified oil from water, achieving an 80% permeance recovery after six filtration cycles. This contributes to environmental sustainability and technological advancements in various industrial applications.