Biorefining and Remediation Laboratory, Department of Process Engineering and Applied Science, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3J 1Z1, Canada.
Solid State Pharma Incorporation, 1489 Hollis Street, Halifax, Nova Scotia B3J 3M5, Canada.
Int J Biol Macromol. 2022 Nov 30;221:426-434. doi: 10.1016/j.ijbiomac.2022.09.017. Epub 2022 Sep 6.
The cellulose nanocrystals (CNCs) were produced from spruce wood using less hazardous and toxic reagents with understanding of influence of process parameters on CNCs properties. This study employed acetosolv pulping followed by alkaline-peroxide bleaching, eliminating highly reactive chemicals such as Na-chlorites and Na-sulfite for cellulose pulp extraction from spruce wood. Cellulose pulp yield of 41.5 ± 0.7 wt% of dry wood was obtained from pulping followed by bleaching treatment. Cellulose pulp was hydrolyzed with 59.0-65.0 wt% sulfuric acid followed by ultrasonic treatment to produce CNCs. CNCs yield of 8.0 ± 3.2 wt% of dry wood was obtained at 65 wt% acid concentration and yield of 25.1 ± 0.7 wt% at 62 wt% acid concentration. The optimization of acid hydrolysis and ultrasonic treatment resulted in CNCs with high aspect ratios (length/width) up to 48.1. It was demonstrated that higher acid concentration requires lower intensity of ultrasonic treatment for CNCs dispersion, and that higher intensity could enhance aspect ratio without impacting the crystallinity index. However, ultrasonic treatment for longer than 5 min led to destruction of the whisker morphology of CNCs. The extracted CNCs possess high crystallinity index of 80.8 ± 1.7 %, low residual hemicellulose (<2.0 %) and lignin (<0.7 %), and high-char content of 26.7 wt% from thermal degradation.
采用危害性和毒性较小的试剂，从云杉木材中生产出纤维素纳米晶体（CNCs），并了解工艺参数对 CNCs 性能的影响。本研究采用乙酰醇法制浆，然后进行碱性过氧化物漂白，避免使用高反应性化学物质，如 Na-次氯酸盐和 Na-亚硫酸盐，从云杉木材中提取纤维素浆。经过制浆和漂白处理，可获得 41.5±0.7wt%的干木材纤维素浆产量。纤维素浆用 59.0-65.0wt%硫酸水解，然后进行超声处理，以生产 CNCs。在 65wt%酸浓度下，可获得 8.0±3.2wt%的干木材 CNCs 产率，在 62wt%酸浓度下，可获得 25.1±0.7wt%的产率。对酸水解和超声处理进行优化，可得到高达 48.1 的高纵横比（长度/宽度）的 CNCs。结果表明，较高的酸浓度需要较低的超声处理强度来分散 CNCs，而较高的强度可以提高纵横比，而不会影响结晶度指数。然而，超声处理时间超过 5 分钟会导致 CNCs 的须状形态遭到破坏。提取的 CNCs 具有高结晶度指数（80.8±1.7%）、低残留半纤维素（<2.0%）和木质素（<0.7%）以及高达 26.7wt%的热降解产率高残炭含量。
