Hydrodistillation-Based Essential Oil Extraction and Soda Pulping of Spent Hemp Biomass for Sustainable Fiber...

Hemp (Cannabis sativa L.) is increasingly valued not only for its fibers and seeds but also for essential oils derived from floral by-products. This study investigates the extraction of essential oils from three hemp floral varieties, Sour Space Candy, Suver Haze 3N, and Pinewalker 3N using hydrodistillation, a widely accepted and efficient method for isolating volatile compounds. The chemical composition and quantification of key volatiles, including α-pinene, β-myrcene, α-humulene, and α-terpineol, were analyzed using gas chromatography-mass spectrometry (GC-MS). In addition to oil extraction, the residual spent biomass was repurposed into pulp fibers using the soda pulping process. Fiber properties such as freeness, viscosity, kappa number, and fiber length were evaluated for papermaking applications. The essential oil yield ranged from 1.24% to 1.86% (w/w), and the spent fiber yield ranged from 37.07% to 55.23%. Handsheets prepared from blends of spent fibers and hemp hurd fibers exhibited tensile indices ranging from 21.87 to 34.98 N·m/g. This dual-valorization approach enhances the economic and environmental value of hemp cultivation, supports sustainable material development, and contributes to the broader adoption of bio-based alternatives.