Cleaner production of cellulose nanocrystals and calcium sulfate whiskers: Process design and life cycle assessment

Abstract

The commercialization of cellulose nanocrystals (CNCs) is currently limited by its environmental impact of high water consumption and brine wastewater generation. Here, a combined process integrating the production of CNCs and calcium sulfate whiskers (CSWs) was proposed to achieve complete utilization of the waste acid, and the corresponding environmental performance was evaluated by life cycle assessment (LCA). Accordingly, we prepared fibrous CSWs with an average length of 309 μm and an average aspect ratio of 57 under optimum conditions. The LCA results demonstrated the superior environmental performance of the combined process, especially for CNC production, and the impact values reduced by 45.6% on average. Moreover, the cost of producing 20 g of CNCs decreased from 3.04 CNY (traditional process) to 1.66 CNY (combined process). Therefore, this combined production process is eco‐efficient and economically scalable for the industrial production of CNCs.