(2z) Sustainable Polymeric Membranes for Molecular Separation- Greener Approach Towards Net Zero Emission

The significant parts of the world’s energy supplied to the industry are used for separation involving seawater desalination, hydrogen production from natural gas, or pharma products that go through extensive separation strategies before being released to the market. As the world moves towards net zero emissions and promises, a sustainable future is possible by employing more innovative and lower carbon footprint separation processes. Due to its advantages over other separation strategies, membrane technology is pivotal. It has been successfully engaged mainly in seawater desalination, petroleum fractionation, natural gas dehydration, purification, and producing pure valuable components in the pharma and health sector. Integrating membrane processes into existing challenging industrial processes depends upon membrane permeance and selectivity. Polymeric membranes have a vast advantage in this research direction due to their flexibility and processibility. Most of these materials need a solvent to make polymer dope to fabricate them in flat sheets or specialized hollow fibers offering more surface-to-volume ratio and packing density. The solvent-non-solvent-induced phase separation process introduces a porous structure during membrane fabrication that decides its final properties and application. Moreover, a critical application like gas separation/purification could be tackled by varying membrane porosity by interfacial polymerization that opens new horizons for membrane applicability.

To fabricate membranes, initially, the polymer is dissolved in a suitable solvent; the solution is cast or spun into a flat sheet or hollow fiber form. The formation of pores in the membranes mainly depends on the type of solvent, polymer composition, set parameters, and additives. The membrane market was established a decade ago, but it's prone to be affected by new regulations toward net zero emission. The regulations on fluorinated polymers and traditional solvents like 1-Methyl-2-pyrrolidone and dimethylformamide pose an imminent threat to the membrane market. Alternative solvents are the best strategy to incorporate in membrane research; this is the right time. After my doctorate, I was more focused on membrane processes that are replacements for energy-intensive strategies used for critical separation. In my 1^st postdoctoral studies, I was focused on developing metal-organic frameworks, promising in greenhouse gas capture and azeotropic separation. Using a simple reduction technique on copper-based MOFs, they separated heptane and toluene based on cationic π–π interaction between reduced MOFs and benzene ring corresponding to toluene. After moving to KAUST, I was exposed to more challenges in advanced membranes and porous material centers. During my arrival year, the kingdom was getting ready for the G20 summit and 2030 vision plans that gave me a boost in writing proposals for membrane production in a sustainable way and translating bench scale results towards prototypes. One of the major projects I was involved in was the KAUST colling initiative to develop an energy-efficient air conditioning system that could save more than 30% of energy compared to the current indirect evaporative cooling system that operates using hydrofluorocarbons. With the guidance of Prof. Suzana Nunes, one of the pioneers of membrane technology, my team developed energy-efficient dehumidification units using polymeric hollow fibers with a coefficient of performance up to 2.5-3. The project was started in April 2019 and ended in December 2022, with the system running continuously for more than 18 months under the harsh Arabian condition with a minimal dip in performance. This motivated us to write a proposal of 1,000,000.00 USD for the translation of this activity. The proposal was accepted in 2021 and ran for more than two years involving hollow fibers and flat sheet module development for gas dehydration and interfacial polymerization towards a sustainable organic solvent nanofiltration process.

As we are stepping towards a greener membrane fabrication process, I have been working previously developing greener coatings for dehydration applications using ionic liquid. The prototype has been run for more than 12 months and efficiently dehydrates the incoming stream with more than 90% of efficiency. When the ECO factor (Greenness parameter) was estimated, we were still on the border of a green process (An Eco factor greater than 75% is considered green). I am currently focusing on deep eutectic solvents (DES) being discussed as potential replacements for harmful solvents. The components for DES are natural menthol and raspberry ketones, present abundantly in nature and are not hazardous to health or the environment. We are spinning hollow fibers using DES and polyetherimide, making it greener, with the ECO factor going above 90% for gas separation applications. We have promising preliminary results that stimulate the further exploration of DES based on natural solvents for fabricating membranes using polymers such as polyimide, polyetherimide, and poly(ethylene terephthalate) (PET). This would open the perspective of using recycled polymer. Exploration of other non-fossil-based polymers, more sustainable fabrication processes, upscaling of the findings, and green metric analysis also sets for our submitted proposal to KAUST innovation grant of 200,000.00 USD that is under consideration. One another factor to consider during cost-cutting strategies are the prototype design. During miniaturization, it's important to have higher packing density in a small area which is possible with hollow fibers.

My master's and doctoral studies from European Union scholarships in Membrane Engineering make me unique. Training in the best labs of the membrane in the world, like the Institute European des Membranes, Montpellier, University of Twente, The Netherlands, University of Zaragoza, Spain, University of Nova de Lisboa Portugal with material science, process optimization and simulations, and membrane technology provide me the enthusiasm as well as solutions for problems faced in separation world. During my journey in KAUST, through a translational grant, our lab acquired spinning, coating, and module-making instruments on a semi-industrial scale. The initial extensive training on instruments by manufacturers and training offered to the other lab personnel gave me distinct skills during my research stay at KAUST. These semi-industrial scales of operations of both flat sheet and hollow fibers are one of the factors that take the research to the next level to fulfill and offer separation solutions towards net zero emission.

Teaching interests

Growing up in a farming family, my dad was an excellent teacher who taught me different farming, crop processing, and storage techniques. He had an immense deep knowledge of concepts used in farming and used the mixed approach of inductive and deductive to transfer his knowledge to me. I was always fascinated with teaching jobs from childhood, and my parents nourished me in every step to achieving my dream as a professor in a university. Growing up and attending different levels of education, I met the best teachers, lecturers, and professors and learned unique techniques from each of them that always encouraged me to pursue a career in teaching. Most people think that delivering a predetermined subject in a timely fashion is the teacher’s job. Teaching is the most sacred job, and it acts as a valuable mentor, excellent tutor, and good evaluator to thousands of young minds who pass through his/her career.

I wish to introduce coursework on sustainable membrane separation and zero carbon emission that will cover the problems faced and strategies for development and implementation. The course should have technological and government perspectives to give an overview of how difficult the way is and how we could improve it. The new course work should provide graduate students to think about green processes and contribute towards zero emissions. I had great opportunities to mentor masters and doctoral students during my post-doctorate and scientist posts, and I learned that students are eager to work towards afore mentioned subjects but lack the fundamentals to come up with ideas or discussions. I think it's my job to train them early to be equipped with the necessary knowledge to take their journey toward a research career. Wet lab training is one more area on which I want to focus so that undergraduate and graduate students are trained and consider research as one of their career options in the future. I was lucky to train some REU students during my postdoctoral studies in Arkansas. They were gifted but confused with what to do after their undergraduate courses and didn’t know how research laboratory works. That gave me a passion for training more and more undergraduates at the seed level so that when they reach the stage of a sapling, they are independent to make decisions with prior knowledge.