Development of Advanced Thin Film Composite (TFC) Membranes for Water Purification and Renewable Energy Generation
Creators: Aghapour Aktij, Sadegh
Publisher: name: University of Alberta Library
Year: 2024

<p>The increasing global demand for water and energy, driven by ongoing population growth and economic advancement, amplifies the pressures on both ecosystems and finite natural reserves. This scenario presents critical challenges for the global community in ensuring sustainable access to water and energy, further complicated by increased consumption, reducing reserves, and the reduced availability of affordable fossil fuels. In response, there is a concerted push towards diminishing reliance on fossil fuels and exploring secure, cost-efficient, and environmentally friendly alternatives for water and energy provision. Membrane separation technologies offer a promising alternative to traditional separation methods, with advantages including a smaller spatial footprint and improved separation efficiency. Advances in materials science and engineering are propelling the development of membrane technologies, particularly for sustainable and renewable energy production and clean water supply. Notably, nanofiltration (NF) and pressure retarded osmosis (PRO) using polyamide (PA) thin film composite (TFC) membranes have emerged as key technologies in water treatment, wastewater recovery, and energy generation. Despite their advantages, PA TFC membranes face challenges in balancing permeability and selectivity, impacting their performance in water treatment and energy production. This challenge necessitates the development of innovative membrane fabrication strategies that aim to refine the structural composition of the PA layer, thereby enhancing its permeability without compromising solute resistance. The present study conducts a series of systematic experiments aimed at fabricating high-performance TFC membranes characterized by improved permselectivity, antifouling capabilities, and augmented power generation potential, addressing the critical need for sustainable solutions in the face of rising water and energy demands.   First, the study introduces a novel approach to improving the performance of NF membranes by incorporating graphitic carbon nitride (g-C3N4) derivatives and nanocomposites as interlayers on polyethersulfone (PES) supports. This strategic modification results in membranes with superior water permeability, selectivity, and antifouling properties. Specifically, the study demonstrates that interlayered thin film nanocomposite (ITFN) membranes loaded with g-C3N4/CuFe2O4 nanocomposites exhibit a significant increase in water flux and enhanced rejection of contaminants, including dyes and heavy metals. This advancement not only improves the efficiency of NF processes but also extends the applicability of TFC membranes in diverse water treatment scenarios.  Second, the research explores the enhancement of PRO systems through the incorporation of amine-functionalized metal-organic framework (MOF) nanorods (NH2-Ce-BTC) into TFC membranes. This innovative membrane design showcases a remarkable increase in hydrophilicity and power density, achieving a new benchmark in osmotic power generation. The membrane modified with NH2-Ce-BTC, upon optimization of its composition, outperforms both its non-functionalized counterpart and pristine TFC membranes in terms of water flux and power generation efficiency. This breakthrough highlights the potential of MOF nanorods in revolutionizing osmotic power generation, offering a promising solution to the global energy crisis.   We also explored the synthesis and application of Co-polyamide (Co-PA) membranes in PRO systems, utilizing a mixture of m-Phenylenediamine (MPD) and piperazine (PIP) as monomers. Employing advanced analytical methods, the membranes were characterized, revealing that PIP integration as a comonomer significantly improves water permeability, salt rejection, and power density, thereby enhancing PRO efficiency. The Co-PA membranes, especially those with optimized PIP content, demonstrate remarkable performance, indicating a significant advance over traditional TFC membranes. Additionally, a life cycle assessment (LCA) further highlighted the environmental advantages of this approach, underscoring the Co-PA membranes&#39; potential in advancing PRO technology towards more sustainable energy generation and water treatment solutions.</p>