Preparation of new self-cleaning and antimicrobial membranes for water treatment in VicInAqua project

Lake Victoria is one the largest freshwater lakes in the world located between Kenya, Tanzania and Uganda. Despite its crucial socio-economic relevance, it is suffering of an overexploitation of its resources and alarming pollution. The aim of VicInAqua EU-project was to provide an innovative, sustainable and integrated approach for water sanitation, through membrane bioreactor (MBR) technology, in Lake Victoria Basin. The core idea of the project was to test and integrate efficient technologies (such as self-cleaning MBR) for the treatment of different types of wastewaters, supplying, at the same time, clean water to a recirculation aquaculture system and agriculture. In order to accomplish this goal, new low fouling, antimicrobial and self-cleaning membrane coatings were developed through the polymerization of polymerisable bicontinuous microemulsions (PBMs) [1,2]. The developed PBM membranes exploited the oxygenic activity of incorporated polyoxometalates catalysts for the displacement of organic foulants through a new chemo-mechanical self-cleaning strategy. The catalysts operate the dismutation reaction of H2O2 to yield O2 and H2O. The in-situ production O2 bubbles was employed as a propulsion force for the dislodgement of foulants deposited at the membrane surface. From the self-cleaning tests carried out, it was shown that the PBM membranes exhibited a regain in water permeability of 46% due to the removal of irreversible fouling. Moreover, the synthesis of a novel class of quaternary ammonium salts (AATEABs), has been explored for their incorporation within the PBM matrix thanks to their antimicrobial properties [3]. The results showed that AATEABs bearing an alkyl chain of 11 and particularly 12 carbon atoms possessed significant activity against Gram+ bacteria and yeast strains.