Alkaline deep eutectic solvent: a novel green solvent for lignocellulose pulping
- 206 Downloads
This work studied the feasibility of potassium carbonate-glycerol deep eutectic solvent (K2CO3-Gly DES) as a potential green solvent applied in lignocellulose pulping. Cellulose fibers were extracted from rice straw via novel alkaline DES pulping technique using 1:7 molar ratio of K2CO3-Gly DES. Optimum pulping parameters were determined using the one-factor-at-a-time (OFAT) method. The cellulose fibers were characterized for chemical composition of cellulose, hemicellulose, lignin and extractives. Changes in physical structure, chemical structure, morphological structure, functional groups and crystallinity index (CrI) were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results revealed that the optimum pulping temperature at 140 °C, reaction time of 100 min and 1:10 rice straw to DES mass ratio produced the highest cellulose content of 73.8% for unbleached DES treated pulp. Chemical composition analysis and FTIR verified that this alkaline DES pulping method was able to achieve partial removal of hemicellulose and lignin from lignocellulosic matrix. Moreover, XRD result demonstrated that the CrI of cellulose fiber increased from 52.8 to 60.0% after pretreatment. The cellulose fibers had diameters ranging from 3.58 to 5.68 µm. This study proved that the specifically-designed K2CO3-Gly DES could successfully isolate cellulose from lignocellulosic biomass through alkaline DES pulping.
KeywordsDeep eutectic solvent Potassium carbonate Glycerol Cellulose pulp Alkaline DES pulping
The authors would like to thank the School of Bioprocess Engineering, Universiti Malaysia Perlis (UniMAP) for their support in this research.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest in the publication.
- Ayeni AO, Hymore FK, Mudliar SN, Deshmukh SC, Satpute DB, Omoleye JA, Pandey RA (2013) Hydrogen peroxide and lime based oxidative pretreatment of wood waste to enhance enzymatic hydrolysis for a biorefinery: process parameters optimization using response surface methodology. Fuel 106:187–194. https://doi.org/10.1016/j.fuel.2012.12.078 CrossRefGoogle Scholar
- Ebrahimi M, Villaflores OB, Ordono EE, Caparanga AR (2017) Effects of acidified aqueous glycerol and glycerol carbonate pretreatment of rice husk on the enzymatic digestibility, structural characteristics, and bioethanol production. Bioresour Technol 228:264–271. https://doi.org/10.1016/j.biortech.2016.12.106 CrossRefGoogle Scholar
- Kumar AK, Parikh BS, Pravakar M (2016) Natural deep eutectic solvent mediated pretreatment of rice straw: bioanalytical characterization of lignin extract and enzymatic hydrolysis of pretreated biomass residue. Environ Sci Pollut Res 23:9265–9275. https://doi.org/10.1007/s11356-015-4780-4 CrossRefGoogle Scholar
- Pilate G, Guiney E, Holt K, Petit-Conil M, Lapierre C, Leplé J-C, Pollet B, Mila I, Webster EA, Marstorp HG, Hopkins DW, Jouanin L, Boerjan W, Schuch W, Cornu D, Halpin C (2002) Field and pulping performances of transgenic trees with altered lignification. Nat Biotechnol 20:607–612. https://doi.org/10.1038/nbt0602-607 CrossRefGoogle Scholar
- Rahnama N, Mamat S, Shah UKM, Ling FH, Rahman NAA, Arif AB (2013) Effect of alkali pretreatment of rice straw on cellulase and xylanase production by local trichoderma harzianum SNRS3 under solid state fermentation. BioResources 8:2881–2896. https://doi.org/10.15376/biores.8.2.2881-2896 CrossRefGoogle Scholar
- Škulcová A, Majová V, Šima J, Jablonsky M (2017) Mechanical properties of pulp delignified by deep eutectic solvents. BioResources 12:7479–7486Google Scholar
- Sluiter A, Hames B, Ruiz R, Scarlata C, Sluiter J, Templeton D, Crocker D (2008) Determination of structural carbohydrates and lignin in biomass. Lab Anal Proced 1617:1–6Google Scholar