(2cj) Improving the Performance of Hollow Fiber Membrane for Energy-Efficient Water Purification

Research Interests: The ever-increasing demand for safe drinking water is an ongoing global challenge. Among the many approaches implemented to alleviate this problem, membrane technology for water treatment is considered a promising solution. Hollow fiber membranes have played a significant role in the advancement of membrane technologies in various industrial sectors due to their financial benefits and ability to be easily assembled in modules for a variety of applications. However, compared to flat sheet membranes, enhancing the area of hollow fiber membranes has been less explored. Because an improvement in flux (which is related to the surface area) along with an increase in rejection significantly minimizes operation cost, modification of hollow fiber membranes which can effectively improve the water quality in seawater and freshwater would have significant economic and societal impacts.

In one of my current projects, a modification strategy was developed to increase the rejection of urea using reverse osmosis (RO) membranes. This strategy introduced carbodiimide chemistry which activated the polyamide layer to attach a diamine. The modified membranes were characterized using ATR-FTIR, SEM, XPS, contact angle goniometry, and electrokinetic analyzer. The addition of a diamine fills in spaces in the molecular structure resulting in a membrane that has higher density and is less porous, yielding higher rejection of uncharged urea molecules. In another project, I am working on the synthesis of novel polyamide RO membranes which will improve the separation of small, neutral uncharged molecules. In order to fabricate the novel membrane, I am synthesizing a new type of acyl chloride monomer that will be used during the interfacial polymerization process.

In my proposed future research, I will apply my expertise in RO membrane synthesis to solve challenging separations problems and improve the energy efficiency of hollow fiber membrane processes. Hollow fiber membranes show promise for desalination. However, operating the hollow fiber membrane at higher pressure is still a major issue because of the flexibility of the fibers, which makes them delicate under high strain. One research project will change the inner geometry of hollow fiber RO membranes by regulating the coagulant fluid composition and flow rate and/or using micro-fabricated needles with characteristic patterns. Change in the inner geometry will increase the surface area and the modified membrane will require less pressure to operate than the unmodified membrane. A second project will synthesize a hollow fiber catalytic membrane incorporated with ceria (CeO₂) nanoparticles to improve the rejection of arsenic (As) in groundwater. According to The International Agency for Research on Cancer (IARC), As in drinking water is a carcinogen in nature, and prolonged consumption of As-contaminated groundwater results in severe health issues like cancer, coronary heart disease, and bronchiectasis. The high surface area of the fiber lumen will offer the benefit of high flux whereas the ceria nanoparticles will catalytically oxidize As (III) to As (V) by H₂O₂. The As (V) will get adsorbed in ceria and as a result, it will enhance the As rejection. Once the ceria nanoparticles are saturated with As (V), the catalytic activity of the ceria nanoparticles will be restored via passing sodium hydroxide inside the fiber lumens. A challenge of this research will be the incorporation of ceria nanoparticles into the membrane system. The outcome of this study will have implications in the area of water treatment and membrane science.

Teaching Interests:

At The University of Alabama (UA), I worked as a teaching assistant for Separation Processes, Chemical Reaction Engineering, and Unit Operations Laboratory. Besides grading, I also covered lectures in the absence of the instructor. In the Unit Operations Laboratory class, I trained students on understanding different unit processes and helped them with troubleshooting the experiments. I also mentored two undergraduate students in my research group. Both of my mentored students presented their posters and won awards at the Undergraduate Research and Creative Activity Conference at UA in 2022. In addition to teaching and mentoring activities, I have participated in two outreach events through UA to engage K-12 students in science through filtration and separation activities. Based on my previous teaching experience and expertise, I look forward to teaching courses related to transport phenomena, reaction engineering, heat transfer, mass transfer, environmental engineering, and polymer science.