Grafting of polyaniline by a dynamic inverse emulsion polymerization technique onto membranes as an anti-biofouling agent: An innovative approach

The demand for clean water is on the rise but since water sources are limited, the need for purification processes, such as membranes and filters, has become increasingly crucial. One of the main hurdles facing these processes is fouling and biofouling. In general, fouling is related to the deposition of macromolecules, colloids, particles and inorganic materials on the membrane surface and pores. Biofouling consists of the deposition of large bacterial colonies and biofilm on the membrane surface and inside the pores. Both are difficult to clean effectively. Anti-biofouling additives are typically insufficient, since they need to be stable to the water current and located at the surface of the membranes or filters. One of the suggested methods for effective biofouling prevention is the use of electrically conductive polymers (ICP).

This work describes an innovative approach for the anti-biofouling protection of membranes. This approach consists of a novel in-situ interfacial dynamic inverse emulsion polymerization process under sonication of aniline in the presence of carbon nanotubes (CNT) and graphene nanoparticles in organic solvent. The resulting hybrids were filtered, and the remaining filtration cake was used and analysed as a nanocomposite membrane.

The resulting polyaniline (PANI) chains were grafted to the membrane surface, creating an anti-biofouling coating. High-resolution scanning electron microscopy (HRSEM) indicated that the nanocomposite membranes were coated with PANI. The grafted PANI exhibited a remarkably improved anti-biofouling effect. The membranes` salt rejection and flow properties were analysed and showed that the flow properties were only slightly different compared to the reference membrane.