Combining the European chemicals regulation and an (eco)toxicological screening for a safer membrane development

Membranes are permeable or semi-permeable barriers used to separate a wide range of particulate and dissolved compounds in liquid or gas. Polymeric membranes for water applications are arousing great interest as potentially cost-effective answers to a growing range of separation needs in different sectors. Although the polymeric membrane is not considered as toxic, the raw materials and additives used during the membrane manufacturing could be hazardous for human health and the environment. The aim of the present study was to evaluate the toxicity and ecotoxicity of chemicals used for phase inversion manufacturing of polyvinylidene difluoride (PVDF) and polyethersulfone (PES) membrane, and the REACH compliance analysis of these chemicals and membrane. The results show that 2 of 9 substances, the N,N-Dimethylacetamide (DMA) and 1-Methyl-2-pyrrolidone (NMP) solvents used for, or potentially present in, membrane are identified under REACH either as a substance of very high concern (SVHC). However, the identification of DMA and NMP as SVHC does not encompass any use restrictions. Among raw materials, the tetrahydrofuran (THF) showed evidence of carcinogenic potential, while the toluene of possible reproductive toxicant. Washing and drying procedures are usually applied by manufacturer to remove solvents to the extent possible. However, how residual solvents may be released during the life cycle of membrane and affect membrane toxicology profile are still open issues. In summary, we argue that to improve sustainable of phase inversion membrane, it is necessary to minimize the input of hazardous solvents, and to simultaneously stimulate the search for alternative eco-friendly solvents.