Reusability of Discarded Tubular Ceramic Membranes for CO₂ Removal: A Case Study for Membrane Circularity

Discarded polymeric or ceramic membranes are currently in need of appropriate and sustainable management. In the present study, the direct reuse of discarded ceramic membranes in membrane contactor (MC) systems for CO₂ removal was investigated for the first time. The hydrophobic surface modification of the discarded ceramic membrane was done by using macromolecule additive coating. The influence of operational parameters (absorbent liquid flow rate (Q_L), feed gas flow rate (Q_g), and different NaOH concentrations) of the MC on CO₂ removal was investigated to prove the technical feasibility of reused ceramic membranes. The CO₂ absorption flux was 7.9 × 10^-4 mol/m² s at optimal conditions of 2 M NaOH, Q_L (20 mL/min), and Q_g (300 mL/min) with a removal efficiency of 98%, which lasted for 8 h. This study demonstrates a potential alternative for the reuse of discarded ceramic membranes and avoids their disposal in landfills. The proposed approach will also bring membrane technology into the circular economy and achieve sustainability goals by reducing the amount of waste from discarded ceramic membranes in the future and combating global warming by absorbing CO₂.