Deep eutectic solvent delignification: Impact of initial lignin

Abstract

This study aimed to resolve the issue of the lack of detailed understanding of the effect of initial lignin content in hardwood kraft pulps on pulp delignification by deep eutectic solvents. The authors used Kappa number of the concerned pulp, intrinsic viscosity, and selectivity and efficiency of delignification as the parameters of the effect. The pulp (50 g oven dry pulp) was treated with four different DESs systems based on choline chloride with lactic acid (1:9), oxalic acid (1:1), malic acid (1:1), and system alanine:lactic acid (1:9); the results were compared to those reached by oxygen delignification. The results showed that the pulp with a higher initial lignin content had a greater fraction of easily removed lignin fragments.

Delignification of Low-Energy Mechanical Pulp (Asplund Fibers) in a Deep Eutectic Solvent System of Choline Chloride and Lactic Acid

“…Wood delignification through deep eutectic solvents (DESs) has arisen as a potential and green alternative for the pulping process where lignin and hemicellulose (and their derived low molecular weight polymers) are obtained as products in addition to cellulose fibers (Majová et al, 2017;Satlewal et al, 2018;Smink et al, 2019;Fiskari et al, 2020;Jiang et al, 2020). DESs are mixtures of at least two components, one of which acts as a hydrogen-bonding acceptor (HBA), and one is a hydrogenbonding donor (HBD) (Hansen et al, 2021).…”

“…The melting point of a DES is lower than either of the individual components due to their strong hydrogen-bonding interaction (Lynam et al, 2017;Schuur et al, 2019). In current studies, several DESs have been tested on the delignification of lignocellulosic materials (Lynam et al, 2017;Majová et al, 2017;Jablonsky et al, 2018;Satlewal et al, 2018;Li et al, 2019;Smink et al, 2019;Fiskari et al, 2020;Jiang et al, 2020;Wang et al, 2021), as well as DES solutions (Soares et al, 2021). Lactic acid and choline chloride (LA:ChCl) DES has shown to be a potential DES for biomass delignification (Jablonský et al, 2015;Alvarez-Vasco et al, 2016;Kumar et al, 2016;Zhang et al, 2016;Liu et al, 2019;Oh et al, 2020) including wood chips (Smink et al, 2019) and Asplund fibers (Fiskari et al, 2020).…”

“…The main objective was to optimize the operating conditions of the DES treatment. The research investigated various operating conditions of DES treatment based on a mixture of lactic acid and choline chloride, which many researchers have studied previously (Majová et al, 2017;Li et al, 2019;Smink et al, 2019;Da Costa Lopes et al, 2020;Fiskari et al, 2020). The investigated parameters included cooking time, cooking temperature, liquor-to-wood ratio (L/W), and the type of mixing (mechanical stirring or a rotatory flask).…”

Effective and Selective Extraction of Quercetin from Onion (Allium cepa L.) Skin Waste Using Water Dilutions of Acid-Based Deep Eutectic Solvents

“…Based on the last property, DESs are fruitfully applied in extraction and preconcentration procedures from different matrices, encompassing vegetal and biological ones [ 39 , 40 ]. One of the most interesting areas where DESs are finding relevant results is in their use as green liquids for biomass feedstocks treatments, where they are finding high effectiveness [ 41 , 42 , 43 , 44 , 45 ].…”

Insight into the deep eutectic solvent pretreatment of oil palm empty fruit bunches: Effects of temperature, empty fruit bunch to solvent ratio, and time

“…A DES is an eutectic liquid mixture of two or three components, which has the ability to establish a hydrogen bond interaction between the hydrogen bond donor (HBD) and the hydrogen bond acceptor (HBA) (Kalhor and Ghandi 2019). Majová et al (2017) discussed the recovery of DES after pretreatment of biomass for further use, by subsequent evaporation of anti-solvent or simple freeze-drying of the washed solutions. Recently, DESs have been proposed as worthy alternatives for lignocellulose biomass dissolution (Zhao et al 2013;Xia et al 2014).…”