PVDF-Halloysite-Ceria multifunctional membrane for one-step treatment to industrial effluent

Abstract

Industrial wastewater, containing diverse pollutants like dyes and oils, poses detrimental environmental challenges. Membrane technology addresses this complexity well but requires tailored nanofiller modifications that enhance hydrophilicity, oleophobicity, and antifouling potential for efficient separation. In this context, our work focuses on the development of mixed matrix membranes (PV-H-C) – PVDF, halloysite nanotubes (HNTs), and ceria nanoparticles – for effective dye and oil-water emulsion separation, enabling high flux recovery. The tubular structure of HNTs, with a lumen, enables the encapsulation and controlled distribution of ceria nanoparticles, preventing their agglomeration and leading to more uniform dispersion within the membrane matrix. HNTs porous structure, high surface area, and numerous adsorption sites within its nanotubes excel in rapid dye adsorption and ceria’s inherent hydrophobic properties along with low surface energy, forms a barrier against oil adhesion and spreading. Optimal results were achieved by loading 2% HNT and 1% ceria in the PVDF matrix, ensuring improved membrane performance. HNTs enhanced hydrophilicity and achieved pure water permeate flux of 1698 L/m2.h.bar. Developed membranes are super-oleophobic with an underwater contact angle of 132° + 3° and show a 100% increase in dyes and oils separation efficiency as compared to the pristine PVDF membranes. This unique integration of ceria with halloysite nanotubes in PV-H-C membranes is pivotal, bestowing exceptional anti-fouling characteristics and reusability, while providing a one-step, comprehensive solution for the effective treatment of complex industrial wastewater that encompasses both oil and complex dyes.