New generation of semipermeable membranes with carbon nanotubes for water and wastewater treatment: Critical review

Abstract

Environmental applications of carbon nanotubes (CNTs) have recently attracted worldwide attention due to their excellent adsorption capacities and promising physical, chemical and mechanical properties, as well as the preparation of novel membranes with attractive features for water purification. This paper critically reviews the recent progress on the preparation and applications of CNT based membranes in water and wastewater treatment. Various synthesis techniques for the preparation of CNT based membranes are discussed. The functionalization of CNTs, which involves chemical/physical modification of pristine CNTs with different types of functional groups, improves the capabilities of CNT for water and wastewater treatment and/or removal of waterborne contaminants. The CNT-based membrane applications are found to possess a variety of advantages, including improving water permeability, high selectivity and antifouling capability. However, their applications at full scale are still limited by their high cost. Finally, we highlight that CNT membranes with promising removal efficiencies for respective contaminants can be considered for commercialization and to achieve holistic performance for the purpose of water treatment and desalination. This paper may provide an insight for the development of CNT based membranes for water purification in the future. With their tremendous separation performance, low biofouling potential and ultra-high water flux, CNT membranes have the potential to be a leading technology in water treatment, especially desalination.