Surface Design of Liquid Separation Membrane through Graft Polymerization: A State of the Art Review

Abstract

Surface modification of membranes is an effective approach for imparting unique characteristics and additional functionalities to the membranes. Chemical grafting is a commonly used membrane modification technique due to its versatility in tailoring and optimizing the membrane surface with desired functionalities. Various types of polymers can be precisely grafted onto the membrane surface and the operating conditions of grafting can be tailored to further fine-tune the membrane surface properties. This review focuses on the recent strategies in improving the surface design of liquid separation membranes through grafting-from technique, also known as graft polymerization, to improve membrane performance in wastewater treatment and desalination applications. An overview on membrane technology processes such as pressure-driven and osmotically driven membrane processes are first briefly presented. Grafting-from surface chemical modification approaches including chemical initiated, plasma initiated and UV initiated approaches are discussed in terms of their features, advantages and limitations. The innovations in membrane surface modification techniques based on grafting-from techniques are comprehensively reviewed followed by some highlights on the current challenges in this field. It is concluded that grafting-from is a versatile and effective technique to introduce various functional groups to enhance the surface properties and separation performances of liquid separation membranes.

Recent Advances in Separation and Analysis of Chiral Compounds

“…Graft copolymers and conjugated microporous polymers (CMPs) have received much attention in recent years. These materials contribute to more intrinsic and controllable chiral pores in polymer membranes to improve both selectivity and permeability.…”

“…Furthermore, the transport from facilitated mechanism to retarded mechanism has been discussed based on new materials. 126 Graft copolymers 127 and conjugated microporous polymers (CMPs) 128 have received much attention in recent years. These materials contribute to more intrinsic and controllable chiral pores in polymer membranes to improve both selectivity and permeability.…”

Highly efficient aramid fiber supported polypropylene membranes modified with reduced graphene oxide based metallic nanocomposites: antimicrobial and antiviral capabilities

“…These hybrid polymeric membranes can acquire novel attributes by incorporating a variety of additives into the membrane casting solutions, tailored according to the desired membrane functionality, spanning inorganic to organic compounds. 5 Polymeric membranes with inherent antibacterial properties are rare. A support or pure polymer membrane does not confer antibacterial features; these are imparted by adding specic modifying compounds to the membrane's polymer matrix, bolstering the membrane's bactericidal capabilities.…”

Preparation and properties of polyester fibers with polyacrylamide hydrogel grafted by UV‐irradiation

“…Chemical grafting demands long grafting time, complicated operation, and easily lead to side reaction at high temperature. 10 However, UV-grafted reactions offer benefits such as process simplicity and inexpensive equipment. This approach can lead to successfully functional modification without compromising the material properties, thus widely applied in the field of surface modification.…”

“…But plasma initiation requires vacuum equipment and strict conditions. Chemical grafting demands long grafting time, complicated operation, and easily lead to side reaction at high temperature 10 . However, UV‐grafted reactions offer benefits such as process simplicity and inexpensive equipment.…”