Accelerated Dewatering of Thick All-cellulose Nanofiber Mats by Air Pressure Application

Abstract

Even though making thin sheets of cellulose nanofiber by a papermaking-like process is straightforward, obtaining thicker papers or plates is extremely time consuming. Dewatering is exceedingly slow due to the enormous number of hydroxyl groups on the surface of nanocellulose that hinders water flow. This study proposes a simple device that speeds up dewatering through the application of air pressure on the aqueous suspension being filtered. A relative pressure of 0.5 MPa reduced the dewatering time of 72 hours for a conventional vacuum filtration to 16 hours, without compromising the mechanical properties of the final molded material.