Fouling resistant superhydrophilic membrane

• Main Author: Gong, Zhuang Ming
• Other Authors: Darren Sun Delai
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Environmental engineering::Water treatment
• Online Access: https://hdl.handle.net/10356/158261
• Institution: Nanyang Technological University

Fouling in membrane systems is one of the most commonly encountered issues in wastewater treatment processes. Simply put, this results in a decreased amount of treated effluent or increase in operating costs associated with the higher energy demand required to pump the feed at a higher pressure. Given that fouling is such a major problem in wastewater treatment, there have been numerous measures developed to control and mitigate it. One such strategy involves the use of chemicals as both a preventive and corrective measure against fouling. While chemicals remain as a popular fouling control measure, there are still certain drawbacks and limitations that have yet to be addressed. For example, the regular usage of chemicals contributes significantly to the operating costs of the treatment plant due to the inherent costs of the chemicals themselves. Additionally, unwanted byproducts such as toxic chemical sludge is generated, and extra costs associated with the handling and disposal of such waste also contributes to the overall operating costs. Hence, there is a motivation for current wastewater treatment plants to reduce their dependency on chemicals and focus on more sustainable methods for fouling control. A shift away from chemicals could be facilitated by the adoption of novel technologies such as nanocomposite membranes, which is a type of membrane functionalised with nanomaterials embedded within the membrane itself. In this study, the fabrication and performance of a silver nanocomposite membrane are investigated. Silver has been used as a biocide for millennia and is non-toxic to humans, making it suitable for such an application. Silver was incorporated both within the polymeric matrix as well as the surface of the membrane in order to maximise the active surface area of the membrane. Characterisation was then carried out to determine the extent of silver growth on the membrane and this was followed by various performance tests to evaluate its suitability for water treatment. The results obtained indicate that the silver growth had significantly increased the wettability and hence pure water flux of the membrane. Antibacterial properties were also displayed against E. coli and S. aureus strains of bacteria. Results obtained from the humic acid filtration test showed superior performance in terms of flux when compared to an unmodified membrane. This study has shown that the silver nanostructures had greatly improved the performance of the membrane in terms of biofouling and organic fouling resistance. It also shows the potential for such membranes to be used in water treatment plants to reduce the use of chemicals for fouling control.