Increasing demand for energy, mismanagement of plastics, and climate crisis call for sustainable solutions to produce fuels, platform chemicals, and materials. Efficient utilization of non-conventional feedstocks like lignocellulosic biomass and waste plastics is essential to reduce the dependence on fossil fuels and mitigate the negative environmental impact. Developing advanced technologies for a sustainable and circular economy necessitates a fundamental understanding of complex reaction systems. In this seminar, I will discuss the application of experimental and computational approaches to obtain insights into the reaction mechanism of complex macromolecules. The first part of the talk will focus on developing experimental methods to study the fast pyrolysis kinetics of lignocellulosic biomass using cellulose as a model compound. Experimental pyrolysis studies often have heat and mass transport effects coupled with reaction kinetics making it challenging to identify the primary decomposition mechanisms. Coupling micro-reactors with comprehensive analytical tools like GC×GC-FID/TOF-MS and a customized GC enabled the detection of permanent gases and bio-oil vapors, including water. This approach allowed the identification of apparent differences in the decomposition pathways of amorphous and crystalline cellulose, indicating the influence of chain arrangement on cellulose pyrolysis. In the second part of the talk, I will present the glycolytic depolymerization kinetics of condensation polymers for monomer recovery. Condensation polymers, like polyethylene terephthalate (PET), have unique sequences of repeating units arranged in a semi-crystalline morphology. Continuum models do not facilitate tracking structural and morphological changes during depolymerization. A kinetic Monte Carlo (kMC) framework has been developed to study the impact of crystallinity, distributions of polymeric, and low molecular weight species as a function of reaction time and reactor temperature. Mapping reaction events over time has allowed the discovery of the changes in underlying glycolytic pathways, which is essential for catalyst selection. These examples emphasize the need for synergistic approaches to address the grand challenges of the 21st century.
SriBala Gorugantu is a postdoctoral researcher with Prof. Linda Broadbelt at Northwestern University, where she develops mechanistic models of thermoplastics for monomer recovery. Her future lab will focus on the reaction engineering of complex systems with applications in the areas of energy and sustainability. She received her Ph.D. in Chemical Engineering from Ghent University (Belgium), advised by Prof. Kevin Van Geem, where she investigated the fast pyrolysis kinetics of lignocellulosic biomass and its model compounds to produce green chemicals using state-of-the-art experimental techniques. Prior to that, she pursued a research-based M.S. in Chemical Engineering from the Indian Institute of Technology Madras and a B.E. in Chemical Engineering from BMS College of Engineering in India. SriBala received research grants from EU COST-SMARTCATs action and CWO-UGent for short-term research visits to Politecnico di Milano (Italy) and Northwestern University. She also received a scholarship from DAAD for an exchange visit to the Karlsruhe Institute of Technology (Germany). In 2021, she was selected as one of the MIT Rising Stars in Chemical Engineering.