Enhancement of nanohybrid PES-nanosilica performance for CO2CH4 separation through combined UV irradiation and thermal annealing treatments

Abstract EN

Basically, the pristine polyethersulfone membrane has a relatively low performance for selective permeation of CO/CH, gasses.

The incorporation of various inorganic nanoparticles has been studied to enhance the permselectivity of the membrane.

Unfortunately, the existence of inorganic species in the polymer matrix often forms less selective voids as a result of low affinity between nanoparticles and the membrane.

In this study, membrane surface modification comprising of UV irradiation and thermal annealing was performed to improve the permselectivity of nanohybrid polyethersulfone membrane for CO/CH, separation.

The polyethersulfone-SiO₂ nanohybrid membranes were fabricated via a nonsolvent induced phase separation (NIPS) method and subsequently modified using UV light irradiation and thermal annealing treatments.

The experimental results showed that 10 min UV irradiation on pristine polyethersulfone membrane enhances membrane's selectivity from 1.25 to 3.75 due to the formation of free radicals in numerous sites of the membrane surface.

However, a longer irradiation time leads to the reduction of membrane's selectivity to 1.08 due to polymer degradation by the free radicals.

The combined UV irradiation and SiO₂ incorporation to the membrane exhibited a synergistic effect where the permeability of CO₂ and CH improved from 70.69 to 9425.84 and from 40.40 to 706.94 GPU, respectively, whilst the selectivity increased from 1.75 to 13.33.

The nanohybrid membranes showed the best permselectivity performance when they are UV irradiated for 15 min and thermally annealed at 180°C for 20 s to achieve 33.33 of selectivity.

This study revealed that UV irradiation and thermal annealing were able to increase the attachment of the SiO₂ nanoparticles, which finally increase the permselectivity performance for CO/CH, separation.