Date of Graduation
12-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Engineering (PhD)
Degree Level
Graduate
Department
Biological and Agricultural Engineering
Advisor/Mentor
Kim, Jin-Woo
Committee Member
Sakon, Joshua
Second Committee Member
Clausen, Edgar C.
Third Committee Member
Zhu, Jun
Keywords
Life Cycle Assessment; Miscanthus x. giganteus; Nanocellulose; Techno-Economic Assessment
Abstract
Cellulose nanocrystals (CNCs), derivatives of an abundant biopolymer, i.e., cellulose, are emerging as promising alternatives to petrochemical-based products due to their unique properties, including biodegradability, low toxicity, high strength, low density, large surface area and low coefficient of expansion. CNCs have diverse applications ranging from food packaging and textiles to drug delivery and medical implants, etc. Despite their potential, the widespread commercialization of CNCs faces significant hurdles owing to the high environmental burden and production costs. They are mainly driven by the commonly used source utilized for CNC synthesis i.e., wood and the intensive synthesis process i.e., requirement of pretreatments before pulping followed by strong sulfuric acid hydrolysis. Therefore, to enhance the commercial viability of CNCs, it is essential to reduce pretreatment requirements, optimize acid hydrolysis process, along with utilizing an alternative source with favorable properties. In our study, we investigated the potential of Miscanthus x. giganteus (MxG), a non-wood lignocellulosic biomass, as an alternative cellulose source for CNC production due to its excellent intrinsic properties, such as low lignin content, high cellulose content, and loosely bound fibers. In the first objective, we investigated the requirement of pretreatment prior to pulping followed by optimizing the sulfuric acid hydrolysis process for efficient CNC production. The study revealed that, in comparison to our in-house wood-based optimized process, the optimized sulfuric acid-based CNC synthesis process from MxG yielded high-quality CNCs with substantially higher yield and offered environmental and economic benefits. The second objective investigated a mixed acid hydrolysis method, combining sulfuric acid and acetic acid, a recyclable organic acid, for CNC production from MxG. While the mixed acid process produced lower CNC yields than the optimized sulfuric acid method, environmental and economic assessments highlighted its drawbacks due to higher usage of acids, raw materials and utilities. Conclusively, our study established MxG as a promising and sustainable alternative to traditional wood-based cellulose sources for CNC production, with sulfuric acid-based synthesis method as a more efficient option than the mixed acid hydrolysis approach. These findings represent a crucial step towards scalable CNC production, supporting their potential for widespread applications. Further optimization of the synthesis process has the potential to enhance production efficiency, reduce costs, and lower environmental impacts, thereby facilitating the commercial success of CNCs.
Citation
Kaur, J. (2024). Synthesis and Process Optimization of Cellulose Nanocrystals from Miscanthus x. giganteus for Commercial Viability. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5587
