The Influence of Potassium Hydroxide Concentration and Reaction Time on the Extraction Cellulosic Jute Fibers

ABSTRACT

A common method used to obtain cellulosic fibers is alkalinization with NaOH. Depending on NaOH content, treatments remove significant quantities of lignin and hemicellulose as small molecules. In biorefineries, where the preservation of components is needed, KOH may prevent hemicellulose chain formation. Here, we studied the efficacy of obtaining cellulosic fibers from jute using KOH. Jute fibers are about 84.2% holocellulose, which corresponds to 59.5% alpha cellulose and 24.7% hemicellulose. To obtain high cellulosic fiber yields from jute, effects of pulping with different KOH concentrations and altering reaction times were studied using factorial planning (2²). Afterward, in natura and treated fibers were characterized via Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and derivative thermogravimetry. Holocellulose sample components were obtained by removing lignin. Factors including concentration and reaction time individually significantly affected cellulose yield. Alpha cellulose was produced when higher levels of the factorial planning conditions were applied. Ideal parameters for cellulose extraction included the addition of 10% (w/v) KOH for 3 h. FTIR analysis was used to ensure that lignocellulosic components were removed by fiber treatment. TG showed that treated fibers were thermally stable at temperatures close to, or higher than, in natura fibers.

摘要

获得纤维素纤维的常用方法是用氢氧化钠碱化. 根据NaOH的含量，处理可以去除大量的小分子木质素和半纤维素. 在需要保存组分的生物精炼厂中，KOH可防止半纤维素链的形成. 本文研究了用KOH从黄麻中提取纤维素纤维的效果. 黄麻纤维约为84.2%的全纤维素，相当于59.5%的α纤维素和24.7%的半纤维素. 为了从黄麻中获得高纤维素纤维产量，采用析因规划（22）研究了不同KOH浓度和改变反应时间的制浆效果. 然后，采用傅立叶变换红外光谱（FTIR）、热重分析（TG）和导数热重分析（dst）对天然纤维和处理后的纤维进行了表征. 通过去除木质素得到了纤维素样品组分. 浓度和反应时间等因素对纤维素产率有显著影响. 当应用更高水平的析因规划条件时，产生α纤维素. 纤维素提取的最佳工艺条件为:;添加10%（w/v）KOH，提取3h. FTIR分析用于确保通过纤维处理去除木质纤维成分. 热重分析表明，处理后的纤维在接近或高于天然纤维的温度下具有热稳定性.

KEYWORDS:

• Alpha cellulose
• holocellulose
• jute fiber
• factorial planning
• alkalinization
• thermal properties

关键词:

• α纤维素
• 全纤维素
• 黄麻纤维
• 因子规划
• 碱化
• 热性能

Acknowledgments

The authors would like to thank CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for providing a scholarship for the first author and FAPDF (Fundação de Apoio à Pesquisa do Distrito Federal) and CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for the financial support for this project.

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Federal District Research Support Foundation [0193.001794/2017]; Decanato de Pós Gradução (DPG), Universidade de Brasília.