Feasibility analysis of SO₂ absorption using a hydrophilic ceramic membrane contactor

Hydrophilic ceramic membranes would be potential candidates for membrane gas absorption if they could be applied to appropriate separation processes. This study highlights a novel concept for the practical implementation of SO₂ absorption in hydrophilic ceramic membrane that exhibits outstanding thermal and mechanical stabilities. With this aim, we investigated experimentally the performance of SO₂ absorption into aqueous sodium hydroxide (NaOH) solution in a hydrophilic alumina (Al₂O₃) membrane contactor in terms of SO₂ removal efficiency and SO₂ mass transfer flux, and compared the performance with that in a hydrophobic one. A series of experiments were performed at various conditions over a NaOH concentration range of 0–1.0 mol·L^{− 1}, a liquid flow rate range of 30–180 ml·min^{− 1}, a gas flow rate range of 120–1000 ml·min^{− 1}, an inlet SO₂ concentration range of 400–2000 μl·L^{− 1}, and a temperature range of 10 –35 °C. It was found that the hydrophilic membrane was more competitive when using a NaOH concentration higher than 0.2 mol·L^{− 1}. Furthermore, it can be inferred that the hydrophilic α-Al₂O₃ membrane exhibited exceptional long-term stability under 480 h continuous operation.