Nafion/TiO₂ nanoparticle decorated thin film composite hollow fiber membrane for efficient removal of SO₂ gas

In this work, thin film nanocomposite (TFN) membranes for SO₂ gas removal have been fabricated by incorporation of PEBAX and Nafion/TiO₂ (hereafter referred as Nf/TiO₂) nanoparticles on a polyethersulfone hollow fiber membrane substrate. Membrane structure, inner coating, and thickness were confirmed by SEM cross-sectional images. In addition, morphological and structural analyses of the membranes were performed using FTIR, SEM, EDX, TEM, and AFM. To investigate the effects of Nf/TiO₂ nanoparticles on the gas permeation performance, four membrane modules with different mass concentrations of Nf/TiO₂ – 0.025, 0.050, 0.075, and 0.1 g – were fabricated. The gas permeation experiments were performed with pure SO₂, N₂, and CO₂ gases and a mixed gas (SO₂/CO₂/N₂) within a pressure range of 1–3 bar and feed gas flow rate of 0.03–0.15 L/min. The obtained experimental results suggest that the addition of Nf/TiO₂ nanoparticles improved the membrane performance by introducing sulfonate and hydroxyl functional groups to the membrane, and thus increased SO₂ permeation and selectivity. The SO₂ permeation was found to be 411–1671 GPU in the range of the studied parameters. The ideal selectivities achieved for SO₂/N₂ and SO₂/CO₂ were 2928 and 72, respectively. Overall, an SO₂ removal efficiency of 93% was achieved by using the Nf/TiO₂ incorporated TFN membrane.