Dissertation Defence: Sustainable Cellulose Composite Aerogels Derived from Agricultural Biomass for Advanced CO₂ Capture Applications
September 25 at 2:00 pm - 6:00 pm
Maryam Firouzi, supervised by Dr. Sumi Siddiqua, will defend their dissertation titled “Sustainable Cellulose Composite Aerogels Derived from Agricultural Biomass for Advanced CO₂ Capture Applications” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Civil Engineering.
An abstract for Maryam Firouzi’s dissertation is included below.
Examinations are open to all members of the campus community as well as the general public. Please email sumi.siddiqua@ubc.ca to receive the Zoom link for this exam.
Abstract
The increasing concentration of atmospheric carbon dioxide (CO₂) from industrial activities has become a major environmental concern due to its contribution to global climate change. Among various carbon capture technologies, post-combustion carbon capture has emerged as one of the most practical approaches for reducing CO₂ emissions from industrial flue gases.
Within this technology, adsorption has attracted considerable attention because of its high efficiency, low energy requirement, and regeneration potential. Metal–organic frameworks (MOFs) and zeolites have demonstrated excellent CO₂ adsorption performance owing to their high surface area and well-developed pore structures. However, their powder form limits practical applications because of poor handling, mechanical instability, and regeneration challenges. Incorporating these materials into a porous supporting matrix provides an effective strategy to overcome these limitations.
Cellulose, the most abundant natural polymer, is a renewable and sustainable substrate for fabricating composite adsorbents. In this study, hemp bast fibres and flax stems, two abundant Canadian agricultural residues, were utilized as cellulose sources. To avoid conventional extraction methods that rely on harsh chemicals, cellulose was extracted using environmentally friendly deep eutectic solvent (DES) systems. The extraction conditions were optimized using Response Surface Methodology (RSM), while machine learning models were developed to predict cellulose extraction performance and improve process optimization.
The extracted cellulose was subsequently used to fabricate lightweight composite aerogels by freeze-drying with synthesized UiO-66 and zeolite 13X at different filler loadings to determine the optimum composition for CO₂ adsorption. The extracted cellulose and fabricated aerogels were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) surface area analysis. The results confirmed the successful extraction of cellulose and fabrication of highly porous composite aerogels.
Composite aerogels containing 70 wt% filler exhibited the optimum balance between structural integrity and adsorption performance. The hemp-based UiO-66 composite aerogel achieved the highest CO₂ adsorption capacity of 2.32 mmol g⁻¹.
Overall, this research demonstrates a sustainable strategy for converting agricultural waste into high-value cellulose-based composite aerogels for CO₂ capture, contributing to biomass valorization and supporting circular economy principles.
