Hollow fiber membrane
contactors have several advantages that make
them a good alternative to conventional absorption processes in the
gas industry, and they have attracted the interest of many researchers.
However, critical issues such as wetting hinder applications of membranes
on a wide scale. Wetting is the penetration of the liquid absorbent
through membrane pores, reducing mass transfer and consequently affecting
the CO2 absorption efficiency and lowering the effectiveness
of the separation process. The availability of membranes that can
maintain a high efficiency and remain stable over a long period of
operation is the main factor that is required in order to implement
membranes in the industry for absorption processes. The wetting phenomenon
in hollow fiber membranes is the focus of this review, which offers
a critical examination of the literature published on membrane wetting,
highlighting the main factors that control the effectiveness of the
membrane separation process. These factors include the liquid absorbent,
the membrane morphology represented by pore size and porosity, and
the mutual interaction between liquid absorbents and the membranes.
All of these factors are discussed in detail in view of a better understanding
of the wetting phenomenon. Furthermore, methods and approaches to
prevent wetting in addition to perspectives for future research in
the area are presented.