Cellulose acetate-based membranes for the removal of heavy metals from water in the context of circular economy

Abstract

Heavy metals are a significant class of water pollutants. Their main source is represented by human activities performed in most of the industrial fields (e.g., leather, textiles, electronics, mining, etc.). The consequences of heavy metal exposure on human health are major and involve neurological, endocrine or protein metabolism impairments. The removal of these pollutants from water represents a practical challenge due to the small size of these chemical species, and due to the stable combinations that they can form with other classes of substances such as drugs or protein. Membrane technology is currently the favorite choice for water treatment, however, the impact of the discarded membranes on the environment represents an issue that needs to be solved. In the current context of circular economy, gradual reduction of synthetic petroleum-based polymers for membrane production and their replacement with natural and biodegradable alternatives is recommended. This review aims to present the latest research carried out in the field of heavy metals removal from contaminated water using cellulose acetate membranes. Membrane modification techniques such as functionalization and the synthesis of composite membranes for improved metal ion retention and filtration performances are presented. Also the polymer’s limitations and future prospects are discussed at the end of this review.