Sustainable and alternative fiber production from industrial hemp hurds: bench and pilot scale assessment

Abstract The sustainable development of high-quality fibers from agricultural waste biomass offers a promising pathway for next-generation fiber-based food packaging and composite products. This study evaluates fiber production from hemp biomass using environmentally friendly approaches, including chemical-free autohydrolysis (AH), soda (alkaline) pulping (AL), and mild kraft pulping (HK), followed by peroxide and elemental chlorine-free (ECF) bleaching. Both bench-scale experiments and a pilot-scale soda pulping trial were conducted to evaluate the industrial scalability and feasibility of converting low-value agricultural residues, specifically hemp hurds, into high-quality fibers. Among the pulping methods, autohydrolysis resulted in the highest fiber yield, followed by lab-scale soda pulping, pilot-scale soda pulping, and mild kraft pulping. However, autohydrolysis exhibited limited delignification, as indicated by a high kappa and low pulp viscosity. In contrast, mild kraft pulping produced the lowest fiber yield but achieved higher fiber quality due to increased delignification. Following ECF bleaching, the kraft pulp (HKC) showed the highest brightness, lowest residual lignin content, and highest viscosity, indicating well-preserved cellulose integrity. AL and HK fibers exhibited lower coarseness and fines content, along with enhanced crystallinity and improved fiber morphology. Peroxide- and ECF-bleached AH fibers showed the highest anionic charge and carboxyl content, indicating strong potential for further chemical modification. While AH fibers are more suitable for molded and hygiene products, HK and AL fibers show greater potential for fiber-based food packaging and composite applications, contributing to the development of a circular bioeconomy. Graphical abstract