Using a systematic review to develop a cellulose nanocrystals production framework for use as a design baseline and optimization tool

Abstract

Various cellulose nanocrystals (CNC) production processes are not systematically reviewed. Therefore, there lacks a basis for future CNC process designs and optimizations. To solve this problem, the objective of this study was to perform a systematic review of selected CNC processes using the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) guidelines to review the process information from each selected literature item to identify the common process segments to create a segmented CNC production framework. The results revealed four major CNC production segments: feed pretreatment, chemical treatment, separation, and product purification. Statistical data analysis indicated that varying forms of mechanical pretreatment comprised 100% of the lignocellulosic feedstock pretreatment. However, the most common chemical treatment, separation, and product purification options are acid hydrolysis (60–75%), mechanical separation (40–60%), and washing (20–50%), respectively. The technology options explored within each segment created a design basis for CNC production improvements to assist the design of new CNC production plants and the optimization of existing ones. The model can also help improve the understanding of the minimum protocol content and improve the competency of process designers.