Novel pre-treatment and fractionation method for lignocellulosic biomass using ionic liquids

Abstract

An efficient lignocellulosic biomass pre-treatment is a crucial step for the valorization of these kind of raw materials. Lignocellulosic biomass is a potentially valuable resource for transformation into biofuels and bio-based products. The use of ionic liquids as media for the biomass pre-treatment is an alternative method that follows the green chemistry concept. This work proposes a new methodology for wheat straw pre-treatment with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([emim][OAc]), which allowed the production of cellulose, hemicellulose and lignin-rich fractions in a rapid and simple three-step fractionation process. Various temperatures (80-140 uC) and processing times (2-18 h) of the pretreatment were studied. The quantitative and qualitative analysis of each lignocellulosic biomass fraction was determined by FTIR measurements. The glucan content in recovered cellulose-rich fractions was investigated by enzymatic hydrolysis. The cellulose recovery dependence on the pre-treatment conditions was ascertained through regression analysis. The optimal result for the recovery of the cellulose-rich fraction was obtained at 140 uC during 6 h achieving 37.1% (w/w) of the initial biomass loading. For the same conditions, optimal results were also produced regarding the amount of glucan present (81.1% w/ w biomass ) in cellulose-rich fractions, the carbohydrate enrichment in the hemicellulose fraction (96% wt) and the purity of lignin (97% wt). The recovery of IL was performed after each pre-treatment and the obtained yields were up to 86% (w/w). The recovered ILs were analyzed by 13 C and 1 H NMR. The presence of value-added phenolic compounds in the recovered ILs was analyzed by capillary electrophoresis. Vanillin and its derivatives, as well as other lignin-based products, were identified.

Combination of Brønsted and Lewis Polymeric Catalysts for Efficient Conversion of Cellulose into 5‐Hydroxymethylfurfural (HMF) in Ionic Liquids

“…[11] So far, ILs are promising green solvents, have been widelya pplied in cellulose-to-HMFc onversion. [12,13] Simultaneously,i nt erms of the lower production of waste,t he use of fewer toxic reagents, and easier recycling over conventional liquid acids, solida cid catalysts have been proposed during the past few years. [14][15][16][17] Thet ransformation of cellulose into furfurals generally involvesm ultiple steps, [18,19] namely,d epolymerization, isomerization, and finally dehydration to HMF.…”

A Bibliometric Study of Scientific Publications regarding Hemicellulose Valorization during the 2000–2016 Period: Identification of Alternatives and Hot Topics

“…The first category, which can be represented by the articles in positions 1, 7 and 9 [82][83][84], covered a global approach to biomass fractionation and valorization by implementation of biorefineries. The second category, which can be represented by the articles in positions 5, 6 and 10, included the papers more specifically focused on the valorization of cellulose and hemicellulose fractions of lignocellulosic biomass [85][86][87].…”

Extraction and electrochemical detection of capsaicin and ascorbic acid from fresh chilli using ionic liquids

“…20-fold larger volume of ethanol using the reported optimised process 6. [Emim][OAc] is known for its ability to dissolve a range of lignocellulosic biomass 37,38. The bottom half ofFig.…”