Dewatering Behavior of a Wood-Cellulose Nanofibril Particulate System

Abstract

The novel use of aqueous suspensions of cellulose nanofibrils (CNF) as an adhesive/binder in lignocellulosic-based composite manufacture requires the removal of a considerable amount of water from the furnish during processing, necessitating thorough understanding of the dewatering behavior referred to as “contact dewatering”. The dewatering behavior of a wood-CNF particulate system (wet furnish) was studied through pressure filtration tests, centrifugation, and characterization of hard-to-remove (HR) water, i.e. moisture content in the wet furnish at the transition between constant rate part and the falling rate part of evaporative change in mass from an isothermal thermogravimetric analysis (TGA). The effect of wood particle size thereby particle specific surface area on the dewatering performance of wet furnish was investigated. Permeability coefficients of wet furnish during pressure filtration experiments were also determined based on Darcy’s law for volumetric flow through a porous medium. Results revealed that specific particle surface area has a significant effect on the dewatering of wet furnish where dewatering rate significantly increased at higher specific particle surface area levels. While the permeability of the systems decreased over time in almost all cases, the most significant portion of dewatering occurred at very early stages of dewatering (less than 200 seconds) leading to a considerable increase in instantaneous dewatering when CNF particles come in contact with wood particles.

Flexible polyurethane foams reinforced with organic and inorganic nanofillers

“…30 CNF is reported to have a potential application as a binder. 31 Dewatering procedures have also been studied focusing on the use of CNF as a binder to other cellulosic particles, 32,33 and the application of CNF to reinforce natural fiber yarns. 34 Spraydried CNF is reported to replace conventional polyols by Leng et al 35 A high amount of CNF (40% polyol substitute or 20% loading level) is reported to disrupt cell structure while improving the cross-linking of CNF-PU and increasing compressive strength.…”

Modeling Microwave Heating and Drying of Lignocellulosic Foams through Coupled Electromagnetic and Heat Transfer Analysis

“…The mixture was placed into a 3D-printed acrylonitrile butadiene styrene (ABS) mold which was then placed on a wire mesh. During this step, clear water was drained due to contact dewatering [37]. The solids content prior to drying was approximately 10 wt.%.…”

Towards sustainable production and utilization of plant-biomass-based nanomaterials: a review and analysis of recent developments

“…The dewatering behavior of CNFs mixed with wood particles of different sizes or specific surface areas was investigated [ 247 ]. Results showed that dewatering rate by pressure filtration of CNFs mixed with wood particles was significantly improved using particles with high specific surface area compared with pure CNFs alone.…”