Open Access

ARTICLE

NaOH/Urea Swelling Treatment and Hydrothermal Degradation of Waste Cotton Fiber

by Lixia Gao, Sheng Shi, Wensheng Hou, Shuhua Wang, Zhifeng Yan, Chao Ge

1 College of Textile Engineering, Taiyuan University of Technology, Jinzhong, 030600, China
2 Jihua 3542 Textile Company Limited, Xiangyang, 441000, China

* Corresponding Author: Sheng Shi. Email:

(This article belongs to the Special Issue: Renewable materials for sustainable development)

Journal of Renewable Materials 2020, 8(6), 703-713. https://doi.org/10.32604/jrm.2020.09055

Received 08 November 2019; Accepted 24 March 2020; Issue published 12 May 2020

Abstract

In this study, waste cotton fabric was used as cellulose raw material and pretreated in aqueous NaOH/urea solution system to investigate the effect of NaOH/urea pretreatment solution on the hydrolysis of cotton fiber. The cotton fiber was pretreated with different conditions of aqueous NaOH/urea solution, and the pretreated cotton fiber was hydrolyzed under the same conditions as the original cotton fiber. The results of characterization analysis showed that water retention value of pretreated cotton fiber was higher than that of unpretreated sample. Moreover, the cotton fiber presented both a convoluted structure and a coarser surface, XRD results suggested that the crystallinity degree of cellulose decreased dramatically, more cellulose II appeared, and the hydrogen bond is broken. Among the different pretreatment conditions, the pretreatment effect was the best when the reaction temperature was 0°C, the solid-liquid ratio was 2:50, and the NaOH/urea ratio was 7:12. The hydrolysis experiments of pretreated and unpretreated cotton fibers showed that when the hydrothermal temperature was 230°C, the heat preservation was 2 h, and the hydrochloric acid concentration was 5 wt. %, the glucose yield reached 29.99%. H⁺ could catalyze the hydrolysis of cotton fiber more effectively due to damage to crystal structure and hydrogen bonds.

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