Porous membranes as gas-liquid contactors are widely used in carbon dioxide (CO2) absorption systems. It provides larger mass
transfer area and excellent operational flexibility. Membrane contactors have been considered as alternative to conventional
approaches in removing CO2. In spite of its advantages over conventional technologies, membrane wetting is a major problem
which reduces performance of CO2 absorption. This paper explains the concept of membrane wetting phenomenon and its influence
on the CO2 mass transfer through the membrane and absorption performance. The factors that cause membrane wetting were
presented including hydrophobicity of membranes surfaces, membrane pore size, liquid entry pressure and properties of absorbent
liquid. Current proposed methods to alleviate the membrane wetting were reviewed and discussed. Development of mathematical
model was presented for all types of membrane wetting modes, as well as its validity for CO2 physical and chemical absorption.