Eco-friendly poly (ε-caprolactone) based Microfiltration polymeric membranes - influence of dope composition on morphology and performance concerning oil-water separation

This work introduces the fabrication of eco-friendly poly (epsilon-caprolactone) based polymeric membranes for water filtration applications by a non-solvent induced phase inversion method by using N-methyl pyrrolidone as solvent and water as non-solvent. The membranes are prepared with good morphological features and permeation properties to fit filtration applications by varying the polymer concentration in the dope solutions in the range of 10-18%. The thermal, mechanical, chemical composition, and surface roughness properties of the fabricated poly (epsilon-caprolactone) membranes were studied by thermo gravimetric analysis (TGA), universal testing machine (UTM), fourier transform infrared spectroscopy (ATR-FTIR), and atomic force microscopy (AFM) respectively. Morphological studies of the membranes showed a porous asymmetric structure with different skin layer morphology. Precipitation kinetics studied by cloud point measurement showed instantaneous demixing during precipitation resulting in fingerlike morphology. Hydrophilicity and the performance of the prepared membranes for filtration applications were analyzed by contact angle measurements, equilibrium water content, porosity, and pure water flux. Pore size measured using ImageJ software and the Guerout-Elford- Ferry equation assures the utility of the membranes for the microfiltration process. The soil degradability of the fabricated membranes was also evaluated and the efficiency of the fabricated membranes for oil/water separation was studied with olive oil-water emulsion. All the results obtained revealed the dependence of membrane properties and performance on the casting solution composition.