Development of high performance nanocomposite filtration membranes

The occurrence of potentially harmful micro-pollutant compounds such as pharmaceutically active chemicals (PhACs), hormones, pesticides and endocrine disrupters (EDC) in the water environment has attracted increasing research interest in the last few years. Traditional membrane water processes cannot effectively remove those chemicals due to the potential adsorption in membranes and accumulation in the water treatment cycle. Laccase has been shown as an effective enzyme to remove micro-pollutants and its stability can be improved by immobilization. In this work, both bio-catalytic nanoparticles and bio-catalytic membranes have been prepared for investigation. Laccase was immobilized on both TiO2 nanoparticles and in-house manufactured flat sheet membranes.

Results have shown modified TiO2 can better retain the enzyme activity than the unmodified TiO2 particles. To form bio-catalytic membranes, laccase has been successfully immobilized on TiO2 functionalized membrane using passive adsorption method. The effect of TiO2 modification and membrane post treatment on enzyme adsorption loading and activity were also investigated. Higher enzyme activity with better stability was found for enzyme immobilized on TiO2 nano- structured membrane than on the controlled PES membrane.

We are currently extending this work by conducting kinetics analyses for the immobilized enzyme.