OBSERVATION OF PSF LOADING EFFECT ON DOUBLE LAYER SUBSTRATE STRUCTURE THROUGH SEM IMAGING

Abstract

The earth’s surface is covered in water. However, not all water is safe for consumption. The best example would be seawater. Sea water consists of high concentrations of salt and could cause dehydration or in a worst-case scenario, death. The current method for converting seawater to drinkable water is seawater desalination. The relatively low cost, low energy consumption, short construction cycle, simple equipment and operation, and ease of management are all reasons why reverse osmosis (RO) is currently the most used desalination technology. From previous studies, hydrophilic nanoparticles, such as Silver (Ag), and Titanium Dioxide TiO2 were successfully incorporated. These nanoparticles have a considerable influence in terms of salt rejection and anti-fouling capabilities which will increase the water flux of the membrane, and fouling will be decreased, resulting in improved membrane performance. However, in previous studies, it was shown that high loading of nanoparticles will result in lower salt rejection performance. This happened due to the integrity of the membrane structure that is compromised by the agglomeration of nanoparticles. To further improve the structure of Psf substrate, application of double layer substrate is applied in fabrication. This is where a layer of dope solution is casted onto an existing solution. For this study, a first layer is fabricated by casting a dope solution consisting of 84.5% of N-methyl2-pyrrolidone (NMP), 0.5% of polyvinylpyrrolidone (PVP), and 15% polysulfone (Psf). This dope solution will be the base layer for the double-layered substrates. In this study, 3 substrates with different concentrations of Psf, that are 5%, 10% and 15% are fabricated. From the SEM Imaging, it proves that this study was completed successfully, as the structure of the substrates fabricated, are like those of other researchers, which is a finger-like structure. However, due to the lack of experience in using a Scanning Electron Microscope (SEM) Imaging, a proper image of the double-layered substrate failed to be captured. Further studies need to be conducted to determine the effects of the double layer on the overall membrane performance.