Life cycle assessment and techno-economic analysis of nanocellulose synthesis via chlorine-free biomass pretreatments

Nanocellulose fibers (CNF) encompass the characteristics of cellulose and nanomaterials, are endowed with great potential for diverse applications. Prior to the extraction of nanocellulose, pretreating biomass to remove lignin and hemicellulose is crucial to ease cellulose isolation at minimal environmental and economic costs. This study presents a comprehensive comparison between acid-chlorite (AC), alkaline peroxide (AP), and hydrogen peroxide-acetic acid (HPAC) treatments, revealing that the latter two total chlorine-free technologies are promising alternatives to AC. Experimental data served as the primary input to the life cycle assessment (LCA) and techno-economic analysis (TEA) to evaluate the quality of CNFs produced and investigate the trade-offs between environmental burden and costs associated with the three bleaching pathways. The FTIR and FESEM analyses showed a successful CNF synthesis regardless of the applied bleaching technique. Notably, CNF-AC was the least eco-efficient at industrial-scale production due to its low yield and the use of chemicals. CNF-AP emerged as the greenest option; however, CNF-HPAC was the most cost-effective with a moderate environmental load for its low electricity consumption, which resulted from the short reaction time required and satisfactory yield. This study highlighted the potential of HPAC technology as a promising alternative to conventional AC treatment in CNF production.