(633f) Dewatering of Cellulose Nanofibers Using Ultrasound

A high-priority goal for advancing the manufacture and broad applications of cellulose nanofibers (CNF) is to address the high-energy requirements associated with dewatering and drying of these materials. Additionally, the current dewatering and drying methods lead to the unwanted issues of agglomeration (loss of nanoscale dimensions), negatively impacting their physical properties. Thus, there is a need for developing an energy efficient dewatering process for CNF with minimum alterations to their physical properties. In this talk, we will describe a new low-cost, low-heat and low-energy method of dewatering CNF based on ultrasound technology. Ultrasonic waves generated using ceramic piezoelectric transducers are applied to the CNF slurry, leading to the formation of instabilities at the liquid-air interface, cavitation, and the subsequent atomization of the trapped liquid from CNF slurries in form of a cold mist. To achieve high throughput, we will discuss a continuous flow dewatering platform as shown in Fig 1, that can facilitate scaleup and optimization of system parameters for desired final dewatered slurry concentration. Our platform achieves ∼70% water removal corresponding to a final solid weight of ∼10% from an initial value of ∼3% of CNF slurry. We also find that our platform achieves significant reduction in energy consumption as compared to other drying methods.