Chemical Kinetics of Alkaline Pretreatment of Napier Grass (Pennisetum purpureum) Prior Enzymatic Hydrolysis

S. Sanni, O. Akinrinola, E. O. Yusuf, O. Fagbiele, O. Agboola
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引用次数: 1

Abstract

Background: Napier grass is a naturally abundant waste material that can be cultivated over a vast area of land which makes it a viable source for sugar and bioethanol production. Introduction: The presence of lignin in the biomass makes cellulose inaccessible for conversion to useful products, however, in order to provide for efficient utilization of the waste material, reagent and energy, a study on the kinetics of lignin removal from Napier grass was carried out in this work using 1 and 3 w/w % NaOH at temperatures between 80 and 120°C. Materials & Methods: Based on the investigation, there was increased lignin removal for increased NaOH concentration. Kinetic parameters were also determined and it was observed that, the reaction of lignin in Napier grass with NaOH obeys a pseudo-zero or pseudo-fractional order kinetics. Furthermore, the orders of the reaction for the pretreatment conditions of 3 w/w% NaOH at 100°C and those of 3 and 1 w/w NaOH at 120°C gave close reaction orders of 0.2, 0.22 and 0.24 respectively after 110 minutes, which implies that, for the three cases, the residual lignin in the extract was almost the same at the pretreatment conditions while slight differences are evident in their pseudo rate constants. Also, it was observed that, the activation energy of the reaction reduced significantly as the concentration of NaOH increased from 1w/w - 3 w/w%. Conclusion: Based on the AIL and the total lignin (i.e. AIL + ASL) in the Napier grass, the recorded delignification efficiencies at the optimum pretreatment time of 17.5 h are 90 and 76% respectively. In addition, the adopted Differential Technique (DT) combined with the Ostwald Method of Isolation (OMI) can be accurately used to study the kinetics of lignin removal from Napier grass.
紫荆草酶解前碱性预处理的化学动力学研究
背景:纳皮尔草是一种天然丰富的废弃物,可以在大面积的土地上种植,这使它成为糖和生物乙醇生产的可行来源。生物质中木质素的存在使得纤维素无法转化为有用的产品,然而,为了提供有效利用废料,试剂和能源,本研究在80至120°C的温度下,使用1和3 w/w的NaOH对纳皮草中木质素的去除动力学进行了研究。材料与方法:通过研究发现,随着NaOH浓度的增加,木质素去除率提高。测定了木质素与NaOH的反应动力学参数,发现木质素与NaOH的反应服从伪零级或伪分数级动力学。此外,100°C条件下3 w/w NaOH和120°C条件下3 w/w NaOH和1 w/w NaOH预处理110 min后的反应级数相近,分别为0.2、0.22和0.24,说明在3种预处理条件下,提取液中残留木质素的级数基本相同,但其伪速率常数略有差异。NaOH浓度从1w/w增加到3w /w%,反应活化能显著降低。结论:以naier草的AIL和总木质素(即AIL + ASL)为指标,在17.5 h的最佳预处理时间下,记录的脱木质素效率分别为90%和76%。此外,采用差分技术(DT)结合奥斯特瓦尔德分离法(OMI)可以准确地研究纳皮草木质素去除动力学。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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