Optimization of lignin recovery from sugarcane bagasse using ionic liquid aided pretreatment

Koel Saha, Jhilly Dasgupta, Sudip Chakraborty, Felipe Antonio Fernandes Antunes, Jaya Sikder, Stefano Curcio, Julio Cesar dos Santos, Hassan A. Arafat, Silvio Silvério da Silva

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


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.

Original languageBritish English
Pages (from-to)3191-3207
Number of pages17
Issue number8
StatePublished - 1 Aug 2017


  • Central composite design
  • Ionic liquid pretreatment
  • Lignin recovery
  • Response surface methodology
  • Sugarcane bagasse


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