(2ba) Sustainable Chemical Manufacturing, Decarbonization, and Waste Management

Decarbonizing the chemical industry and managing carbon waste are two of society's most paramount obstacles in the 21^st century. Transformative approaches will have to be implemented to power the energy sector and handle waste generation in an economically and environmentally beneficial way. Two major societal issues that motivate my research are the insurmountable plastic waste problem and water contamination caused by perfluoroalkyl substances (PFAS) pollution. New materials must be developed for both aims to handle both systems efficiently. My group will also look at using renewably powered energy for separation applications. The main goal of all thrusts will be to substitute energy-intensive processes with more sustainable and economical ones. Specifically, my research enterprise will (I) study molecular interactions of waste plastics and solid catalysts, (II) develop robust, absorbent materials for the separation of PFAS from water, and (III) electrify thermal separations through renewable microwave technology. All three aims will deliver a chemical manufacturing and management approach toward a cleaner, more sustainable economy.

Previous Research

My prior and current research has focused on renewable and sustainable aspects of the energy transition. My graduate research under Carsten Sievers and AJ Medford focused on studying metal oxide catalysts for biomass upgrading using in-situ spectroscopy. Specifically, the role of surface defects, such as oxygen vacancies, in aldol condensation of small oxygenates was investigated on Mo oxide catalysts. Increasing the density of oxygen vacancies on the catalyst surface while preserving the overall bulk structure can enhance activity toward aldol condensation. This project was in collaboration with the Medlin group at CU Boulder. Other projects included developing advanced in situ solid-state NMR tools to understand sugars' interaction with catalytic oxide surfaces and FTIR studies of complex oxygenate adsorption on catalytically relevant materials. Throughout my PhD, I had the unique experience of working closely with three faculty each with distinct expertise. I grew immensely from this exposure, which equipped me with a skillset to think about problems from multiple angles.

My postdoctoral research under Dionisios Vlachos has focused on depolymerizing plastic waste using microwave-assisted heating. My first project was geared to the depolymerization of PET, targeting the formation of long-chain oligomers. We discovered that enhanced swelling of PET causes dissolution, which leads to oligomer formation. These materials' characteristics were studied using various techniques (DSC, TGA, MALDI-TOF, MAS NMR, GPC). The oligomers possess similar properties to PET and excitingly can undergo polycondensation under a simple thermal treatment to reform PET. This is an exciting avenue for chemical recycling as catalytic polymerization can be avoided and this project is being actively explored. My second project deals with the valorization of end-of-life tires. We are the first group to successfully show the extraction of the harmful antioxidant, N-(1,3-dimethylbutyl)-N'-phenyl-1,4-benzenediamine (6PPD), from waste tires. A high-throughput microwave reactor system was developed where large volumes of waste tires can be processed. The additive-extracted waste crumb rubber is subjected to microwave pyrolysis, where high yields of BTX, indanes, naphthalene, and other petrochemicals can be obtained.

Research Interests

Future work in my group will focus on the valorization of end-of-life plastics. Highly robust catalysts will be developed through rational design. Specifically, the interactions of polymers with the surface of solid catalysts will be elucidated. This is motivated by the need for more progress in a fundamental understanding of these chemistries caused by the absence of thorough kinetic and thermodynamic analysis of substrates binding at the catalyst surface. I will leverage the expertise I have developed in graduate school on in-situ spectroscopy with what I have learned on plastic depolymerization in my postdoc. I aim to elucidate electronic and spatial active site environments and substrate (polymer) binding modes on the surface. The ubiquity of PFAS in water has caused heightened alarm at its potential health consequences. Separation of these harmful chemicals will be a core thrust of my group. This will be accomplished through strategic development and characterization of porous materials, elucidation of adsorbent factors that enhance PFAS adsorption, and study of PFAS desorption/recyclability of materials. Finally, my group will research microwave-powered separations. Microwave-powered technology presents a massive upside toward decarbonization due to the ability to heat certain media rapidly and selectively. We aim to study highly relevant mixtures, such as alkenes from alkanes, aromatics derivates, and CO₂ from various mixtures. I will leverage the knowledge I have gained in my postdoc through two projects focused on microwave technology and apply it to this entirely new application.

Mentoring and Teaching Interests

My passion for teaching has motivated me to mentor many students during graduate school and my postdoc. I have directly supervised 8 undergraduates and mentored several junior graduate students from various backgrounds, which has prepared me to serve as a group leader. I have refined my general mentoring style as I supervised more students, but I attempt to tailor how I interact and provide feedback to students in a way that works best for both parties. This preserves the young researcher's individuality and independence while also allowing them to grow into a well-rounded scientist.

In the classroom, I have served as a teaching assistant during college and graduate school. I have served in the following courses: material and energy balances (twice), unit operations, and heat and mass transfer. I am qualified to teach courses in these subjects along with separations and reaction engineering. I will also design a course focused on sustainable technologies for decarbonization by integrating a separations and catalysis perspective. Teamwork and practice are essential for the success of young engineering students. During my office hours and guest lectures, I will encourage students to discuss their problem-solving strategies with classmates to facilitate good communication and critical thinking. As a professor, I am interested in teaching similar courses like those listed, at both the undergraduate and graduate levels.