Preparation and properties of polyethersulfone hollow fiber membranes with o-xylene as an additive used in membrane contactors for CO ₂ absorption

In this work, o-xylene was used as an additive of dope solutions in the preparation of polyethersulfone (PES) hollow fiber membranes by nonsolvent induced phase separation (NIPS) method to improve the hydrophobicity of membrane. The o-xylene concentration was varied from 0 to 10 wt.%. Characterization of the fabricated hollow fiber membranes included scanning electron microscopy (SEM), tensile mechanical strength and water contact angle measurement. Microscopic observation showed that the membranes were composed of macrovoids and finger like structure. Permeation performance was determined; included pure water permeability. The gas permeation method was used to estimate the surface pore size and effective surface porosity of the PES hollow fiber membrane prepared. The o-xylene was used as a pore-reducing agent. The effect of coagulation temperature on the morphology of the hollow fiber membranes was investigated for temperature range 24-60 °C. The fabricated hollow fiber membranes were used to separate carbon dioxide from gas mixture using membrane contactor module. An attempt had been made to find the optimum o-xylene concentration and the effect of the coagulation temperature on membrane morphology and absorption performance. It was observed that addition of o-xylene to the cast solution reduces water permeability, reduced membrane pore size, and increases membrane strength and water contact angle and hence the hollow fiber membranes is more hydrophobic.