The impact of nanoparticle leach on sustainable performance of the membranes – A critical review

Fouling remains a major challenge in membrane-based water treatment technologies. As a result, contemporary research is geared towards membrane surface modification techniques to reduce fouling. Mitigation strategies involving incorporation of nanoparticles (NPs) into polymeric membranes has gained a remarkable interest. However, NPs leach is eminent, particularly with poor support on membranes resulting in secondary pollution. Consequently, aquatic life is threatened depending on the level of toxicity of the leached NPS. Also, these NPs present toxicological effects to other water consumers. Therefore, this work reviews contemporary literature on membrane surface modification techniques paying attention to incorporation of NPs in the membrane polymer matrices. Various factors governing NPs leach are concisely presented. Special attention was focused on stability of the NPs immobilization on the polymeric membrane due to thermodynamic interactions. Similarly, the effects of NPs leach on membrane physicochemical properties and the NPS ecotoxicity are discussed in detail based on literature reports. Different approaches presenting improvement on NP stability in the polymer matrix are discussed. Lastly casting of future perspectives and the impact of NP leach on sustainable performance of the membranes and ecotoxicity is presented.