Leemen Chan

I am Chan Chee Yong Leemen from Singapore, nominated to join this seminar by World Scientific Publishing. In my project, a novel method for designing membrane filters for water purification is developed using recycled plastic and bio-derived chitosan. The active material of chitosan has previously conventionally been used for medical applications but has demonstrated potential for nanofiltration. In this work, we successfully modified chitosan to target various types of dyes during filtration. Raw materials such as polyethylene terephthalate were derived from recycled plastic bottles and turned into porous supports. Chitosan polymer derived from shrimp shells is modified to carry various types of chemical groups to alter its affinity to different molecules, and coated onto the supports to form membrane filters. The efficiency of filtration is then tested using Congo Red, Malachite Green and Methylene Blue dyes to model pollutants. The dye solutions before and after filtration were characterised using UV-Vis spectroscopy. The greater the chemical affinity of the filter for a certain molecule, the more it will be removed from solution. Of the filters tested, those containing unmodified chitosan or chitosan modified with propionic groups demonstrate the highest affinity to highly polar contaminants, removing up to 59.1% of Congo Red dye. Those containing chitosan modified with isobutyryl or benzoyl groups demonstrate the highest affinity to nonpolar contaminants, removing up to 55.1% of Methylene Blue dye. This effective performance of our synthesised membranes illustrates the potential of custom-modified chitosan membranes manufactured from eco-friendly sources as highly selective filters for water purification.