Evaluation of Wetting Behavior of Nanocomposite Polypropylene Hollow Fiber Membrane as a Membrane Contactor for CO2 Removal

Hypothesis: Gas-liquid membrane contactors have been considered as one of the potential alternatives for CO2 removal compared to conventional technologies. However, membranes wetting with liquid absorbents during this process limits membrane contactors application, which indicates the need for the use of hydrophobic membranes in these systems. In recent years, the use of nanoparticles to increase the hydrophobicity of polymer membrane surfaces and fabrication of nanocomposite membranes has been considerably investigated by researchers. In order to reduce the wetting problem of membranes, in the present work, methyl grafted silica nanoparticles (CH3SiO2 NPs) were used to increase surface hydrophobicity of the polypropylene (PP) hollow fiber membranes, which were synthesized by the sol-gel method. Prepared membranes were characterized by ATR-FTIR, XRD, FE-SEM, contact angle, mechanical strength and breakthrough pressure. Findings: The obtained results from ATR-FTIR analysis confirmed the presence of methyl grafted silica NPs on the surface of PP membrane. The results of the contact angle measurement showed that for nanocomposite membranes by increasing the MTES/TEOS molar ratio from 1 to 4, the contact angle increased from 125° to 164°; however, the contact angle decreased with further increase in the molar ratio of MTES/TEOS. Also, with the precision in the results of mechanical strength measurement, it can be seen that the synthesis of NPs on the membrane surface as well as in the cross-section increased the tensile strength of the membrane to 12.8 MPa. Finally, the performance of membranes was investigated in the membrane contactors for CO2 absorption, which results in a significant decrease in the flux for pure membranes compared with nanocomposite membranes