Preparation of novel self-cleaning membranes with anti-biofouling properties to be used for water treatment within the VICINAQUA project

The innovative core idea of VicInAqua EU-project (http://www.vicinaqua.eu/) is to develop, test and integrate novel technologies in a common system for water sanitation and treatment in the Victoria Lake Basin. One the goal of the project consists in the preparation of novel self-cleaning and low bio-fouling membranes for MBR technology for the production of clean water to be reused in aquaculture and agriculture. During the project, novel membranes were, therefore, developed through the polymerization of polymeric bicontinuous microemulsions (PBMs) used as a coating membrane material of commercial ultrafiltration MBR membranes [1]. In order to accomplish the two goals of the project, regarding membrane preparation, two different approaches were followed: Biofouling Remediation: The synthesis of a novel class of polymerizable quaternary ammonium salts, represented by acryloxyalkyltriethylammonium bromides (AATEABs), has been explored for their incorporation into the PBM membrane matrix. All the newly synthesized AATEABs were tested for their antimicrobial activity where the ones bearing an alkyl chain of 11 and 12 carbon atoms were found to have the most significant activity against Gram positive bacteria and yeast strains. Self- cleaning activity: Inorganic catalysts, such as ruthenium based polyoxometalates (Ru4-POMs), were incorporated and chemically bounded into the PBM membrane matrix. Exploiting the ability of these catalysts to allow the dismutation reaction of H2O2 molecule in O2 (as bubbles) and water, a new chemo-mechanical self-cleaning strategy was proposed and developed [2]. In particular, once opportunely activated after fouling formation, the Ru4-POMs catalysts started to produce O2 gas acting as a propulsion force for the mechanical displacement of foulants located at membrane surface. The O2 produced started to clean the surface of the membrane by removing the irreversible foulants deposited on its surface (not removed by simply washing the membrane with water) and achieving a regain in membrane performance (in terms of water permeability) up to 50%.