Dewatering and Rehydration of Cellulose Nanofiber Suspensions Using a Dissolvable Particle

Cellulose nanofibers (CNFs) are typically supplied as a 3 wt.% suspension and this leads to higher costs because of the economics associated with shipping a product that is 97% water. Filter pressing is the common approach to reduce shipping cost as water removal leads to approximately 20 wt.% CNF suspensions. In this manuscript, we describe a method to achieve an approximately 35 wt.% CNF suspension by contact dewatering with a dissolvable particle. In this work, contact dewatering was performed using slightly anionic precipitated calcium carbonate (PCC), anionic ground calcium carbonate (GCC), and cationic GCC. After dewatering, calcium carbonate is removed from the CNF suspension by washing with acidic water, and thus a pure CNF suspension is regenerated. Fiber size analysis and scanning electron microscopy imaging showed that the regenerated CNF suspensions had the same properties as the original supplied suspensions.