Date of Award

2024

Document Type

Thesis - ECU Access Only

Publisher

Edith Cowan University

Degree Name

Doctor of Philosophy

School

School of Engineering

First Supervisor

Masoumeh Zargar

Second Supervisor

Mehdi Khiadani

Third Supervisor

Amir Razmjou

Abstract

The increasing presence of organic contaminants, particularly emerging contaminants like micro or nano plastics (MPs and NPs), and their interactions with other organic matters in water bodies raise significant environmental concerns. Consequently, there is an urgent need for enhanced techniques to efficiently remove these tiny plastics. While polymeric membranes are effective, fouling because of different organic molecules and their interaction with each other remains a major challenge, confirming the effects of different organic foulants such as proteins (e.g., bovine serum albumin, BSA), dyes, and MPs/NPs in membrane fouling. Different types of pressure and non-pressure membranes, including reverse osmosis (RO), forward osmosis (FO), and ultrafiltration (UF), exhibit promising antifouling outcomes due to various improvement strategies such as optimised operation, surface modification, and cleaning methods. Implementing these membranes with optimised structures could mitigate the risks posed by proteins, MPs/NPs, and dyes to both the membrane structure itself and environmental protection in the water and wastewater sectors.

The development of advanced engineered membranes can highly improve the membrane performance including water permeability, rejection capabilities, and strong resistance to fouling. While such membranes have demonstrated promising performance against various foulants, the combined effect of these foulants with MPs/NPs can still diminish membrane efficiency and lifespan. The presence of MPs/NPs in the water and wastewater sector can worsen fouling, especially when interacting with other foulants. Integrating novel nanomaterials into membrane structures is a crucial strategy for enhancing membrane performance and improving antifouling properties. Metal organic frameworks (MOFs), zwitterions, and functionalised multiwalled carbon nanotubes (MWCNTs) as novel porous materials composed of hydrophilic functional groups, are gaining attention for membrane development. The compatibility of these structures with polymer matrix, facilitating water selectivity within the polymer structure. However, the integration of these nanomaterials into polymeric membranes and their interaction with various strategies remains relatively unexplored in membrane separation technology for water and wastewater treatment.

This thesis introduces innovative strategies for incorporating advanced materials into the polymeric structure of membranes, creating mixed matrix structures to improve membrane performance and antifouling properties, particularly against potential emerging foulants such as MPs/NPs. Various materials, including MIL-53(Fe), NH2-UiO-66, NH2-MIL-125, NH2- UiO-66 on NH2-MIL-125, zwitterion, and double layer membranes using NH2-MIL-125 and functionalised MWCNTs were synthesised and characterised with advanced techniques such as XRD, FTIR, DLS, SEM, and BET analysis. These materials were then integrated into different types of membranes such as RO, FO, and UF which were characterised using SEM, FTIR, XRD, AFM, streaming potential, and contact angle measurements. Membrane performance and antifouling behaviour against MPs/NPs and organic foulants were subsequently evaluated, contributing valuable insights into the development of advanced membranes resistant to MPs/NPs fouling.

DOI

10.25958/wyb5-pw30

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