Optimization of lignin recovery from sugarcane bagasse using ionic liquid aided pretreatment
Optimization of lignin recovery from sugarcane bagasse using ionic liquid aided pretreatment
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DOI：
10.1007/s10570-017-1330-x
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发表时间：
2017-05
期刊：
影响因子：
5.7
通讯作者：
Koel Saha;Jhilly Dasgupta;S. Chakraborty;F. Antunes;J. Sikder;S. Curcio;J. C. dos Santos;H. Arafat;S. D. da Silva
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作者：
Koel Saha;Jhilly Dasgupta;S. Chakraborty;F. Antunes;J. Sikder;S. Curcio;J. C. dos Santos;H. Arafat;S. D. da Silva
离子液体1-乙基-3-甲基咪唑乙酸酯（[EMIM]oAc）用于蔗渣（SCB）的预处理和木质素的提取，木质素是生物燃料工业潜在的有价值的副产物。利用响应面法，建立了优化木质素回收率的经验模型，其决定系数R2为0.9890。在最佳预处理条件下，即预处理时间为120 min，温度为140℃，离子液体与甘蔗渣的比例为20:1 (wt/wt)，木质素得率最高可达90.1%。傅里叶变换红外光谱（FTIR）证实木质素中存在愈创木基环和丁香基环；紫外可见分光光度法测定木质素中含有对香豆酸和阿魏酸。热分析表明，在265℃条件下，木质素的最大分解速率为2%/℃，凝胶渗透色谱分析表明，木质素的分子量为1769 g/mol。比较预处理和未处理甘蔗渣的FTIR光谱显示，预处理样品中木质素的存在可以忽略不计。这样就保证了预处理后甘蔗渣的最大脱木质素。通过热重分析，证明了离子液体具有可回收性的热稳定性。本研究确定了清洁和再生（[EMIM]oAc）在从SCB中回收木质素方面的良好性能。
Ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]oAc) was employed for the pretreatment of sugarcane bagasse (SCB) and extraction of lignin, a potentially valuable by-product of the biofuel industry. Response surface methodology based on central composite design was exploited and thereby an empirical model, exhibiting a coefficient of determination, R2, of 0.9890, was established to optimize lignin recovery. In particular, a maximum lignin yield, equal to 90.1%, was calculated at the optimal pretreatment conditions, namely time: 120 min, temperature: 140 °C, and ionic liquid to bagasse ratio equal to 20:1 (wt/wt). The presence of guaiacyl and syringyl rings in lignin was confirmed by Fourier transform infrared spectroscopy (FTIR); whereas UV–Vis spectrophotometry showed that both p-coumaric acid and ferulic acid were contained in the lignin. Thermal analysis indicated a maximum decomposition rate of 2%/°C at 265 °C while Gel permeation chromatography analysis revealed that the molecular weight (Mw) of recovered lignin was equal to 1769 g/mol. Comparison of FTIR spectra of pretreated and untreated bagasse showed a negligible presence of lignin in the pretreated samples. Maximum delignification of bagasse after pretreatment was thus ensured. Thermal stability of the ionic liquid towards recyclability was proven by thermogravimetric analysis. The present study established adequate performance of neat and recycled ([EMIM]oAc) with regard to lignin recovery from SCB.