Efficient and rapid multiscale approach of polymer membrane degradation and stability: Application to formulation of harmless non-oxidative biocide for polyamide and PES/PVP membranes

Abstract

Membrane cleaning & disinfection is a bottleneck in the filtration processes of the food industry. Disinfection by oxidative agents, such as NaOCl, have been clearly identified as the main responsible of the accelerated ageing of polymer membranes. The development of new formulated biocide detergents allowing to respect the integrity of polymer membranes is our objective. A major difficulty to overcome is to have a method making it possible to rapidly demonstrate whether the membrane will age after a long-time contact with the biocide in industrial conditions of use. However, nowadays the estimation of membrane ageing is mainly achieved by long-time consuming methods, limiting biocide & detergent developments. This paper proposes an original approach allowing a time-efficient discrimination of biocide detergent prototypes with respect to the membrane long-term ageing. The methodology is firstly based on the use of microwaves activation to accelerate the membrane degradation (if any) in the biocide solution set at a concentration selected to avoid too severe degradations never reached at industrial scale. Secondly, the combination of MW results and short time filtration gives rapidly relevant information about the suitability (or not) of a tested prototype with respect to the membrane flux behaviour. ATR-FTIR characterisation is shown to be relevant as the single analytical tool to follow the entire approach. Finally, only the promising prototype enter in long-term filtration validation tests, with a real opportunity to avoid unnecessary experiments. For the sake of the demonstration, the methodology is applied aiming at the formulation of a non-oxidative formulated biocide detergent that can be used either for RO or UF. The results evidence a non-intuitive conclusion: the new biocide validated for RO polyamide membrane (fragile toward NaOCl biocide oxidant and hydrophilic) has to be avoided for the more chemically resistant but also more hydrophobic UF PES/PVP membrane.

Polymer/Graphene Nanocomposite Membranes: Status and Emerging Prospects

“…The most important application of polymeric nanofibers concerns membrane technology. In this regard, polymeric nanocomposite nanofibers have been tested [69]. Graphene-reinforced polymeric nanofibers have been used to design nanocomposite membranes [70][71][72][73].…”