{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T14:16:00Z","timestamp":1790172960018,"version":"4.1.0"},"reference-count":44,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,4,27]],"date-time":"2026-04-27T00:00:00Z","timestamp":1777248000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Development and Industrialization of New Technologies for Processing and Utilizing Bamboo, as well as Research and Development of Intelligent Equipment","award":["2025ZCY003"],"award-info":[{"award-number":["2025ZCY003"]}]},{"name":"Scientific and Technological Research Project of Henan Province","award":["262102230114"],"award-info":[{"award-number":["262102230114"]}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"crossref","award":["2025M781853"],"award-info":[{"award-number":["2025M781853"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"crossref"}]},{"award":["2025M781853"],"award-info":[{"award-number":["2025M781853"]}],"id":[{"id":"https:\/\/ror.org\/0426zh255","id-type":"ROR","asserted-by":"publisher"}]},{"name":"National Innovation Training Program for College Students","award":["202510466011X"],"award-info":[{"award-number":["202510466011X"]}]},{"name":"Key Scientific and Technological Project of Henan Province","award":["242102230174"],"award-info":[{"award-number":["242102230174"]}]},{"name":"Standardization of Bamboo and Wood Product Quality and Safety Testing Machines","award":["2025ZCY004"],"award-info":[{"award-number":["2025ZCY004"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>In this study, binary and ternary DES systems were prepared using choline chloride (ChCl) with lactic acid (LA), glycerol (GL), urea, and acrylic acid (AA) to extract lignin from Paulownia. The chemical structure of lignin was analyzed to evaluate the structural changes induced by various DES systems, and the isolated lignin was used to prepare DES gels. The results showed that lignin extracted using different DES systems shares similarities in its basic structural framework, with all samples retaining an intact benzene ring structure. However, there are certain differences in the content of the linking bonds and the S\/G ratio, and the acidic DES caused the breakage of the \u03b2-O-4\u2032 linkage in the lignin molecule, promoting its separation. The molecular weight distribution varied among the DES systems. In the ternary DES, the addition of acrylic acid disrupted lignin\u2019s internal chemical linkages, leading to the precipitation of relatively small lignin molecules. TGA results demonstrated varying levels of thermal resistance among lignin extracted from different DES systems varied, with the best stability observed for lignin extracted from the ChCl-LA system. Lignin extracted from Paulownia using different DES systems was added to the DES gels, and the effects of lignin structure on the properties of the DES gels were investigated. The mechanical, swelling, microstructural, and thermal properties of DES gels prepared from different Paulownia lignin structures showed slight differences; however, no significant discrepancies were observed among the gels. The present work offers a novel strategy for the valorization of lignin derived from lignocellulosic biomass.<\/jats:p>","DOI":"10.3390\/gels12050365","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T09:55:39Z","timestamp":1777370139000},"page":"365","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Separation of Lignin from Paulownia and Its Application in DES Gels"],"prefix":"10.3390","volume":"12","author":[{"given":"Hanyin","family":"Li","sequence":"first","affiliation":[{"name":"College of Forestry, Henan Agricultural University, Zhengzhou 450002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liangdi","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Forestry, Henan Agricultural University, Zhengzhou 450002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaobo","family":"Xue","sequence":"additional","affiliation":[{"name":"College of Forestry, Henan Agricultural University, Zhengzhou 450002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yi","family":"Meng","sequence":"additional","affiliation":[{"name":"College of Forestry, Henan Agricultural University, Zhengzhou 450002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6496-3178","authenticated-orcid":false,"given":"Youming","family":"Dong","sequence":"additional","affiliation":[{"name":"College of Materials Science and Engineering, Nanjing Forestry University, Nanjing 210037, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fei","family":"Xiao","sequence":"additional","affiliation":[{"name":"Hunan Academy of Forestry, Changsha 410018, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7209-4649","authenticated-orcid":false,"given":"Hanmin","family":"Wang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Bio-Based Fiber Materials, Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science and Technology, Tianjin 300457, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5830-155X","authenticated-orcid":false,"given":"Cheng","family":"Li","sequence":"additional","affiliation":[{"name":"College of Forestry, Henan Agricultural University, Zhengzhou 450002, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1246843","DOI":"10.1126\/science.1246843","article-title":"Lignin Valorization: Improving Lignin Processing in the Biorefinery","volume":"344","author":"Ragauskas","year":"2014","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4447","DOI":"10.1039\/D2NA00423B","article-title":"Antibacterial Lignin-Based Nanoparticles and Their Use in Composite Materials","volume":"4","author":"Morena","year":"2022","journal-title":"Nanoscale Adv."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Jakubowski, M. (2022). Cultivation Potential and Uses of Paulownia Wood: A Review. Forests, 13.","DOI":"10.3390\/f13050668"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"118761","DOI":"10.1016\/j.indcrop.2024.118761","article-title":"Assessment of Deep Eutectic Solvents (DES) to Fractionate Paulownia Wood within A Biorefinery Scheme: Cellulosic Bioethanol Production and Lignin Isolation","volume":"216","author":"Collins","year":"2024","journal-title":"Ind. Crops Prod."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"116752","DOI":"10.1016\/j.rser.2026.116752","article-title":"Advances and Challenges in Deep Eutectic Solvents Pretreatment Technologies for Bioethanol Production from Lignocellulosic Biomass: A Comprehensive Review","volume":"231","author":"Novia","year":"2026","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"9142","DOI":"10.1021\/ja048266j","article-title":"Deep Eutectic Solvents Formed between Choline Chloride and Carboxylic Acids: Versatile Alternatives to Ionic Liquids","volume":"126","author":"Abbott","year":"2004","journal-title":"J. Am. Chem. Soc."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"11060","DOI":"10.1021\/cr300162p","article-title":"Deep Eutectic Solvents (DESs) and Their Applications","volume":"114","author":"Smith","year":"2014","journal-title":"Chem. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Wang, S., Li, H., Xiao, L.-P., and Song, G. (2020). Unraveling the Structural Transformation of Wood Lignin During Deep Eutectic Solvent Treatment. Front. Energy Res., 8.","DOI":"10.3389\/fenrg.2020.00048"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4637","DOI":"10.1007\/s10570-025-06553-4","article-title":"Research Progress of Deep Eutectic Solvents in Lignocellulosic Biomass Pretreatment","volume":"32","author":"Zhang","year":"2025","journal-title":"Cellulose"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"5133","DOI":"10.1039\/C6GC01007E","article-title":"Unique Low-Molecular-Weight Lignin with High Purity Extracted from Wood by Deep Eutectic Solvents (DES): A Source of Lignin for Valorization","volume":"18","author":"Ma","year":"2016","journal-title":"Green Chem."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8691","DOI":"10.1021\/acs.iecr.6b01907","article-title":"Review of Alkali-Based Pretreatment To Enhance Enzymatic Saccharification for Lignocellulosic Biomass Conversion","volume":"55","author":"Xu","year":"2016","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1007\/s42114-024-01186-w","article-title":"A Novel Eco-Friendly Bamboo-Based Composite Biochar for Effective Removing Oxytetracycline Hydrochloride","volume":"8","author":"Li","year":"2024","journal-title":"Adv. Compos. Hybrid Mater."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"6550","DOI":"10.1021\/acssuschemeng.8b04936","article-title":"High Performance Thermoplastic Elastomers with Biomass Lignin as Plastic Phase","volume":"7","author":"Huang","year":"2019","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1007\/s42114-024-01195-9","article-title":"Cleaner Production of Liquefied Biomass-Based Phenol\u2013Formaldehyde Resin with Improved Properties via Catalyzed Copolymerization","volume":"8","author":"Li","year":"2024","journal-title":"Adv. Compos. Hybrid Mater."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Xiao, G., Xie, S., Mao, B., Chen, H., Xue, Y., Xu, Q., Guo, J., and Dai, M. (2025). Tailoring Functionalized Lignin-Based Spherical Resins as Recyclable Adsorbents for Heavy Metal Uptake. Polymers, 17.","DOI":"10.3390\/polym17243324"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Liu, C., Ni, S., Wang, Z., Fu, Y., Qin, M., and Zhang, Y. (2025). Direct In Situ Conversion of Both Lignin and Hemicellulose into Single Functional Biopolymers via Biomass Fractionation Process. Polymers, 17.","DOI":"10.3390\/polym17081029"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1016\/j.matpr.2019.06.443","article-title":"Sonochemically Synthesized Lignin Nanoparticles and its Application in the Development of Nanocomposite Hydrogel","volume":"17","author":"Ingtipi","year":"2019","journal-title":"Mater. Today Proc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1007\/s42114-024-01142-8","article-title":"Performance and Mechanism of a Novel Bamboo-Based Magnetic Biochar Composite for Efficient Removal of Norfloxacin","volume":"8","author":"Li","year":"2024","journal-title":"Adv. Compos. Hybrid Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"e19633","DOI":"10.1002\/adma.202519633","article-title":"Polymerizable Deep Eutectic Solvents-Enabled High-Lignin-Density Networks for Ambient Multi-Scale Fabrication of Multifunctional and Extreme Environment Adaptable Soft Devices","volume":"38","author":"Li","year":"2026","journal-title":"Adv. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.ijbiomac.2022.10.111","article-title":"Freeze-Resistant, Rapidly Polymerizable, Ionic Conductive Hydrogel Induced by Deep Eutectic Solvent (DES) after Lignocellulose Pretreatment for Flexible Sensors","volume":"224","author":"Yan","year":"2023","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"117443","DOI":"10.1016\/j.carbpol.2020.117443","article-title":"Cellulose Nanocrystalline Hydrogel Based on A Choline Chloride Deep Eutectic Solvent as Wearable Strain Sensor for Human Motion","volume":"255","author":"Wang","year":"2021","journal-title":"Carbohydr. Polym."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2316","DOI":"10.1021\/acsenergylett.3c00340","article-title":"A Flexible Supercapacitor with High Energy Density Driven by MXene\/Deep Eutectic Solvent Gel Polyelectrolyte","volume":"8","author":"Huang","year":"2023","journal-title":"ACS Energy Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"5120","DOI":"10.1039\/D1GC01512E","article-title":"Lignin Promoted the Fast Formation of A Robust and Highly Conductive Deep Eutectic Solvent Ionic Gel at Room Temperature for A Flexible Quasi-Solid-State Supercapacitor and Strain Sensors","volume":"23","author":"Wang","year":"2021","journal-title":"Green Chem."},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Yang, L., Xing, M., Xue, X., Jin, X., Wang, Y., Xiao, F., Li, C., and Wang, F. (2025). Preparation and Characterization of a Novel Eco-Friendly Acorn-Based Wood Adhesive with High Performance. Forests, 16.","DOI":"10.3390\/f16050853"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"7101","DOI":"10.1039\/D4GC00909F","article-title":"Choline and Lactic Acid Covalently Incorporate into the Lignin Structure during Deep Eutectic Solvent Pulping","volume":"26","author":"Boerkamp","year":"2024","journal-title":"Green Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1515\/npprj-2025-0008","article-title":"Separation of High-Yield and High-Purity Lignin from Elm Wood Using Ternary Deep Eutectic Solvents","volume":"40","author":"Wu","year":"2025","journal-title":"Nord. Pulp Pap. Res. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"e00814","DOI":"10.1002\/marc.202500814","article-title":"High-Performance Phenolic Resin Reinforced by Tannic Acid-Polyethyleneimine Functionalized Multi-Walled Carbon Nanotubes for Wood-Based Panels","volume":"47","author":"Li","year":"2026","journal-title":"Macromol. Rapid Commun."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"116204","DOI":"10.1016\/j.indcrop.2022.116204","article-title":"Assessing the Availability of Bamboo (Phyllostachys Pubescens) Fibers and Parenchyma Cells for Producing Lignin Nanoparticles and Fermentable Sugars by Rapid Carboxylic Acid-Based Deep Eutectic Solvents Pretreatment","volume":"193","author":"Zhang","year":"2023","journal-title":"Ind. Crops Prod."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"5806","DOI":"10.1021\/jf0605392","article-title":"Organosolv Ethanol Lignin from Hybrid Poplar as a Radical Scavenger: Relationship between Lignin Structure, Extraction Conditions, and Antioxidant Activity","volume":"54","author":"Pan","year":"2006","journal-title":"J. Agric. Food Chem."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2474","DOI":"10.1039\/C9GC02569C","article-title":"Novel Insights into Biomass Delignification with Acidic Deep Eutectic Solvents: A Mechanistic Study of \u03b2-O-4 Ether Bond Cleavage and the Role of the Halide Counterion in the Catalytic Performance","volume":"22","author":"Gomes","year":"2020","journal-title":"Green Chem."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Jan\u010d\u00edkov\u00e1, V., and Jablonsk\u00fd, M. (2024). Exploiting Deep Eutectic Solvent-Like Mixtures for Fractionation Biomass, and the Mechanism Removal of Lignin: A Review. Sustainability, 16.","DOI":"10.3390\/su16020504"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"118256","DOI":"10.1016\/j.jece.2025.118256","article-title":"Comparative Insight into Biomass Pretreatment by Choline Chloride-Based Deep Eutectic Solvents in Relation to Their Physicochemical Characteristics","volume":"13","author":"Guo","year":"2025","journal-title":"J. Environ. Chem. Eng."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/j.indcrop.2009.03.004","article-title":"Isolation and Structural Characterization of the Milled-Wood Lignin from Paulownia Fortunei Wood","volume":"30","author":"Rencoret","year":"2009","journal-title":"Ind. Crops Prod."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"113415","DOI":"10.1016\/j.indcrop.2021.113415","article-title":"Microwave-assisted deep eutectic solvents (DES) pretreatment of control and transgenic poplars for boosting the lignin valorization and cellulose bioconversion","volume":"164","author":"Ma","year":"2021","journal-title":"Ind. Crops Prod."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/0040-6031(88)87213-7","article-title":"Thermal degradation of sugar cane bagasse","volume":"125","author":"Ouensanga","year":"1988","journal-title":"Thermochim. Acta"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.pecs.2017.05.004","article-title":"Lignocellulosic Biomass Pyrolysis Mechanism: A State-of-the-Art Review","volume":"62","author":"Wang","year":"2017","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2501624","DOI":"10.1002\/adfm.202501624","article-title":"Skin-Inspired Durable and Cost-Effective Biomass-Based Supramolecular Adhesives","volume":"35","author":"Lei","year":"2025","journal-title":"Adv. Funct. Mater."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"6265","DOI":"10.1021\/acsapm.3c00913","article-title":"Construction and Application of Biobased PDES Ionic Gels with a Soft\u2013Hard Segment","volume":"5","author":"Li","year":"2023","journal-title":"ACS Appl. Polym. Mater."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1016\/j.chphma.2024.07.006","article-title":"Swollen hydrogel nanotechnology: Advanced applications of the rudimentary swelling properties of hydrogels","volume":"3","author":"Wang","year":"2024","journal-title":"ChemPhysMater"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Aziz, T., Farid, A., Haq, F., Kiran, M., Ullah, A., Zhang, K., Li, C., Ghazanfar, S., Sun, H., and Ullah, R. (2022). A Review on the Modification of Cellulose and Its Applications. Polymers, 14.","DOI":"10.3390\/polym14153206"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"6539","DOI":"10.1021\/acssuschemeng.7b00674","article-title":"Interfacial Solid-Phase Chemical Modification with Mannich Reaction and Fe(III) Chelation for Designing Lignin-Based Spherical Nanoparticle Adsorbents for Highly Efficient Removal of Low Concentration Phosphate from Water","volume":"5","author":"Luo","year":"2017","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"120634","DOI":"10.1016\/j.indcrop.2025.120634","article-title":"Efficient Removal of Lignin in Tobacco Stems with Choline Chloride-Based Deep Eutectic Solvents","volume":"226","author":"Yu","year":"2025","journal-title":"Ind. Crops Prod."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"3067","DOI":"10.1021\/cr010439p","article-title":"Some Aspects of the Properties and Degradation of Polyacrylamides","volume":"102","author":"Caulfield","year":"2002","journal-title":"Chem. Rev."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"121567","DOI":"10.1016\/j.indcrop.2025.121567","article-title":"Construction of Zno@Pda Core-Shell Nanoparticle in Antimicrobial Nanofibril Aerogel for Sustainable Oil-Water Separation","volume":"234","author":"Bi","year":"2025","journal-title":"Ind. Crops Prod."}],"container-title":["Gels"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2310-2861\/12\/5\/365\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,29]],"date-time":"2026-04-29T04:14:56Z","timestamp":1777436096000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2310-2861\/12\/5\/365"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,27]]},"references-count":44,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["gels12050365"],"URL":"https:\/\/doi.org\/10.3390\/gels12050365","relation":{},"ISSN":["2310-2861"],"issn-type":[{"value":"2310-2861","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,27]]}}}