(2hq) Thermochemical Modulation of Acid-Containing Siliceous Zeolites for Renewable Chemicals

Renewable 1,3-butadiene (BD, C4H6) can be synthesized from the tandem decyclization and dehydration of biomass-derived tetrahydrofuran (THF) on attenuated solid acid zeolite catalysts. BD is a highly solicited monomer deployed in the synthesis of functional polymers, including cis-1,4- polybutadiene and styrene-butadiene rubber (SBR), primary constituents of tires, and styrene- butadiene latex (SB latex), utilized in the production of carpets and paper-coatings. Recent findings accent the selective conversion of THF to BD on phosphorus-modified siliceous zeolites (P-zeosils) at both, high and low space velocities (catalyst contact time). Noticeably, the efficient production of BD platform chemical requires a profound understanding of the paired-interaction effect of the process variables and conditions on the catalyst activity, selectivity and stability. Correspondingly, probing the effect of water generated during the chemo-catalytic conversion or intrinsic to biomass-derived feedstocks on the catalyst framework and performance is pivotal to the optimization and scale-up of these systems. We have performed a Box-Behnken surface analysis to comprehend and enhance the selective conversion of THF to BD on the Brønsted acid sites (BAS) of Boron (B)-, Phosphorus (P)-, and Sulfur (S)-containing silicalite-1 catalysts at various process conditions; namely, temperature (200-370°C), weight hourly space velocity (1.9-19.1h^-1), and water content in the feed stream (0-10 %). Detailed kinetic measurements revealed that all three catalysts exhibit competitive selectivity to BD ca. 30-99% in the order of P-MFI > S-MFI > B-MFI at both low (0%) and high (10%) water content in the feed stream for conversions 4%. Additionally, the presence of water in the feed promoted the suppression of competing side reactions, thus augmenting BD site time yields (STYs). Markedly, initial P-MFI and S-MFI exposure to water vapor increased THF conversion, but subsequently subsided as evinced by a steepened deactivation profile in a 5-hour time-on-stream analysis. This phenomenon coincides with active site evolution in the presence of water vapor as related to BAS density (e.g., hydrolysis of P-O-P linkages). Overall, this study progresses the ability to control reaction pathways and product selectivity, a headway towards dehydra-decyclization chemistry optimization on microporous zeolites.

Research Interests . Chemo-catalytic probing, and nanotechnology assembly of biomass-derived feedstocks for the efficient design and optimization of sustainable products and systems.

Research vision: Mass producing quotidian commodities from biopolymers.

My research interests involve conducting comprehensive investigations on the properties and characteristics of various types of biomass-derived industrial byproducts and waste products as renewable feedstocks to produce high-value carbon-neutral sustainable products, chemicals and materials. Notably, the efficient and selective chemo-catalytic conversion of biomass-derived oxygenates into bioplastic, rubber and elastomer monomers. Furthermore, the design, synthesis, functionalization and characterization of bio-polymeric nanomaterial, and their structural and chemical optimization for a target end-application. These include including lignin nanoparticles for the controlled release of active materials, and cellulose-lignin nanofibers to produce biological scaffolds and electrochemical electrodes.

Research accomplishments

I conducted by Ph.D. dissertation in the Biofuels and Bio-products Laboratory (Ong Lab) at Michigan Technological University developing novel wood preservatives from black liquor, a byproduct from the pulp and paper industry. In order to achieve this, the first step was to purify the primary wood component in the black liquor, lignin. Lignin is an amphiphilic and chemically active polymer with tremendous potential as a renewable carbonaceous feedstock. Secondly, the optimally recovered lignin was used to synthesize novel, single and double-shelled lignin nanocapcules. Thirdly, these nanocapsules were loaded with a secondary fungicide, propiconazole and their encapsulation efficiency and release profiles were studied. Lastly, the empty, and loaded nanocapsules were impregnated on southern yellow pine wood blocks, and exposed to brown rot fungi degradation, and their singular and synergistic efficacy at combating fungal decay were assayed.

My research project as a postdoctoral associate in the Reaction Engineering and Catalysis Laboratory (Dauenhauer Group) at the University of Minnesota focuses on heterogeneous catalysis probing, and chemocatalytic process elucidation for biomass-derived oxygenates conversion to conjugated dienes through advanced kinetic measurement, and chemical characterization techniques.

Selected publications:

Teaching Interests.

I am passionate about learning and teaching. My motivation to become an educator is the opportunity to inspire, advice, and instill in students the fervor of quality education as a cornerstone for an organized society. I believe that students should grasp the concept that education is meant to improve the quality of their life at every level in their education voyage. I have a strong conviction that diversity and inclusion are key ingredients of impactful teaching, they optimize performance, and promote the organization on a social and racial standard. As such, they are integral tenets of my pedagogical philosophy. My goal is to motivate students to be curious about the fundamental concepts, and the real-world applications of the material they learn in the classroom. Motivate students to critically analyze homework problems as related to the fundamental concepts, and the broader impact (environmental, social and economic) of their solutions. This can be effectively achieved through inter-disciplinary project-based, design-based, and research- based education in multi-cultural teams. As an educator, it is imperative that I approach my duties with full intention, and in accordance with the departmental, and broader university’s educational mission.

I’ve had wonderful experiences working as teaching assistant at the undergraduate and graduate level. These include core chemical engineering courses, and general science and engineering courses. To name a few, applied mathematics for chemical engineers, advanced thermodynamics for chemical engineers, graduate laboratory safety, advanced transport phenomena for chemical engineers, computer-aided problem solving in chemical engineering, mineral processing and extraction (with laboratory). I learned from a wonderful professor that the main goal of imparting a class should not be to assign grades, but rather, to make sure the students master the learning objectives. I have tried to implement this ideal by allowing students multiple attempts at re-submitting homework problems, initiating group discussions during my office hours, and sometimes meeting one on one to work through the problems until they feel confident in the topic. This happens sometimes at the expense of my own free time, but it fills me with so much satisfaction. Moreover, this affable instructor-student relationship gives students the liberty to express their concerns and provide regular feedback about the course and my teaching approaches. These are very valuable to me as they help me improve towards achieving my goal; a warm, friendly, inspiring and motivating teaching-learning environment.

I am excited to teach any core the chemical engineering curriculum at the undergraduate and graduate levels. Moreover, I am interested in developing courses on effective chemical process optimization, and biomass-derived industrial waste recycling and valorization. All the while remaining committed to building a learning environment that critically analyzes the fundamental concepts behind problems, and the broader social, ethical, and environmental impacts of our solutions, in accordance with the university’s educational mission.

Proposal Experience.

Mistletoe Research Fellowship, waitlist candidate, 2021.