Abstract: A mechanism of wettability for hydrophobic membrane was presented based on bi-film theory. Resistance equation, Laplace equation and pore size distribution function of membrane were correlated, and a novel mass-transfer mathematical model was developed. The process of mass-transfer of CO₂ absorption in membrane contactor was studied by using hydrophobic microporous PP membrane and absorbents of water or MDEA(N-methyldiethanolamine) aqueous solution. The effects of wettabilities engendered by pressure difference, surface tension and temperature on mass transfer were investigated. The results show that the model can be used to predict better the mass-transfer coefficients caused by wettability, and the predicted values are in good agreement with the experimental data; wettabilities caused by pressure difference, surface tension and temperature give rise to significant effects on mass transfer and should be taken into consideration in gas-liquid membrane contactor.

Key words: Wettability, Hydrophobic membrane, Mass transfer coefficient, Mathematical model