Preparation and Characterization of Cellulose Nanocrystals from the Bio-ethanol Residuals.
This study was to explore the conversion of low-cost bio-residuals into high value-added cellulose nanocrystals. Two enzymatic hydrolyzed residuals (i.e., HRMMWand HRSPW) were collected from two different bio-ethanol producing processes-hydrolyzing medium-milled wood (MMW) and hydrolyzing acid sulfite pretreated wood (SPW), respectively. The results showed that both residuals contained over 20 wt % glucan with a crystallinity of about 30%, confirming the existence of cellulose in a well-organized structure in two bio-residuals. The cellulose nanocrystals (CNCs) were successfully extracted by first bleaching the hydrolyzed residuals to remove lignin and then hydrolyzing them with sulfuric acid. The resulting CNCs displayed the flow birefringence under two crossed polarizers. Compared with CNCs from microfibrillated cellulose (CNCMCC), HRMMWand its resulted CNC present the smallest particle size and aspect ratio. CNCMCChad the larger particle size, aspect ratio, and higher z-potential value, CNCSPWpresented a similar morphology to CNCMCC, and had the largest aspect ratio. The CNCMCCenhanced its high crystallinity to 85.5%. However, CNCMMWand CNCSPWhad a better thermal stability and higher activation energy as well as onset temperature and maximum decomposition temperature. As a result, the CNCs from bio-ethanol residuals are valued and promising cellulose nanoparticle resources.
College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China. dulanxing@bjfu.edu.cn.|Composite Materials and Engineering Center, Washington State University, Pullman, WA 99163, USA. dulanxing@bjfu.edu.cn.
Lanxing
L
Du
Composite Materials and Engineering Center, Washington State University, Pullman, WA 99163, USA. jinwuwang@fs.fed.us.|Forest Products Laboratory, Forest Service, Department of Agriculture, Orono, ME 04469, USA. jinwuwang@fs.fed.us.
Jinwu
J
Wang
College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China. bjfuzhangyang@bjfu.edu.cn.
Yang
Y
Zhang
College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China. qichusheng@bjfu.edu.cn.
Chusheng
C
Qi
Composite Materials and Engineering Center, Washington State University, Pullman, WA 99163, USA. wolcott@wsu.edu.
Michael P
MP
Wolcott
College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China. yuzhiming@bjfu.edu.cn.
Zhiming
Z
Yu
aspect ratio; bio-ethanol residuals; cellulose nanocrystal; crystallinity; particle size; thermal stability; z potential