Carbon nanomaterial-based membranes for water and wastewater treatment under electrochemical assistance

Membrane separation has been widely used in water and wastewater treatment due to its relatively low cost, easy operation and high efficiency. However, current membranes suffer from a trade-off between selectivity and permeability as well as membrane fouling. Recently, numerous studies have focused on the development of carbon nanomaterial (typically, carbon nanotube and graphene)-based membranes with high performance for water and wastewater treatment. Many studies have demonstrated that benefiting from the good electrical conductivity of carbon nanomaterial-based membranes, their permselectivity and fouling resistance can be further improved under electrochemical assistance. Herein, we review the recent progress in the preparation, mechanisms and applications of electroconductive nanocarbonaceous membranes for water purification and wastewater treatment, aiming at improving the fundamental understanding of the combination of membrane separation and electrochemistry. Firstly, we summarize the recent methods for the preparation of some typical electroconductive membranes, for example, carbon nanotube membranes and graphene membranes. Subsequently, we discuss the underlying mechanisms (e.g., electro-oxidation, electro-adsorption, and electrostatic interactions) for the electrochemically enhanced permselectivity, antifouling and regeneration performance, and finally highlight the practical limitations of membrane/electrochemistry systems and outline possible solutions.

Automated summary

Membrane separation is widely used in water and wastewater treatment due to its cost-effectiveness, ease of operation, and high efficiency. However, current membranes face challenges in balancing selectivity and permeability, as well as dealing with membrane fouling. Recent studies have focused on developing high-performance membranes based on carbon nanomaterials, such as carbon nanotubes and graphene, to improve water and wastewater treatment. These carbon nanomaterial-based membranes demonstrate enhanced permselectivity and fouling resistance under electrochemical assistance, thanks to their good electrical conductivity. This review summarizes the progress in the preparation, mechanisms, and applications of electroconductive nanocarbonaceous membranes for water purification and wastewater treatment, aiming to enhance the fundamental understanding of combining membrane separation and electrochemistry. The review covers methods for preparing electroconductive membranes, such as carbon nanotube membranes and graphene membranes, as well as the underlying mechanisms for the improved permselectivity, antifouling, and regeneration performance achieved through electrochemical processes. The review also discusses practical limitations of membrane/electrochemistry systems and proposes possible solutions.