This study presents CO2 separation using PPO/SiO2 mixed matrix membranes (MMMs) in a membrane contactor. The non-solvent induced phase separation (NIPS) method was used to prepare flat sheet membranes using a commercial grade of PPO (polyphenylene oxide) polymer and 2-Ethyl-1-hexanol as a non-solvent additive. Mixed matrix membranes were fabricated via two approaches; adding the hydrophobic silica into casting solution (approach 1) and into coagulation bath (approach 2). The results showed that the addition of 2-ethyl-1- hexanol (5wt%) to the casting solution improved the membrane porosity by 74.7% while reducing the contact angle from 106.3 to 95.2 ̊. Water contact angle of prepared MMMs by approaches 1 and 2 were found to be around 117.8 and 142.9 ̊, respectively indicating that silica could enhance the membrane hydrophobicity in both methods. The maximum CO2 absorption flux and removal efficiency were attained about 5.8 × 10-3 (mol.m-2.s-1) and 64.8 % for MMM with 2 wt.% silica in approach 1. Meanwhile, MMM obtained with silica content (2 g.L-1) from approach 2, indicated CO2 flux of 5 × 10-3 (mol.m-2.s-1) and removal efficiency around 55.8 %. The long-term performance of prepared MMMs was evaluated during 20 days of operation. The results confirmed the long term stability of prepared samples and good interaction between the silica particles and the PPO polymer in scenario of approach 2.

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