Natural deep eutectic solvent for cellulose isolation from almond shell powder: A sustainable approach for by-product valorization
[EN] Cellulose was isolated from almond shell through different pretreatments: a conventional 7.5 % NaOH method and a natural deep eutectic solvent method using choline chloride:urea (2:1), both treatments carried out at 80 degrees C for 4 h. A control without pretreatment was also included. All sam...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/231876 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/231876 |
| Access Level: | acceso abierto |
| Palabra clave: | Cellulose Natural deep eutectic solvent Lignocellulosic biomass |
| Sumario: | [EN] Cellulose was isolated from almond shell through different pretreatments: a conventional 7.5 % NaOH method and a natural deep eutectic solvent method using choline chloride:urea (2:1), both treatments carried out at 80 degrees C for 4 h. A control without pretreatment was also included. All samples underwent subsequent bleachings with NaClO2 (1.3 %, 2 h, 75 degrees C, twice) and with NaOH 10 %:H2O2 6 %:H2O (1:1:100) (1.5 h, 60 degrees C). Pretreatment with ChCl:urea proved to be the most effective, removing up to 90.1 % of lignin and increasing cellulose content from 28.4 to 63.2 g/100 g dry matter. Fourier Transform Infrared Spectroscopy confirmed lignin removal through 1726 and 1125 cm(-)(1) bands attenuation. X-Ray analysis indicated cellulose enrichment up to a 68 % (p < 0.05) in crystallinity. Thermogravimetric analysis revealed improved thermal stability, with degradation onset and peak temperatures between 250 and 271 degrees C and 355-360 degrees C, respectively, due to reduced amorphous content. High whiteness (average 86.7 %) was observed after bleachings. SEM micrographs confirmed cellulose fibrillation accompanied with a decrease in the degree of polymerization. These results highlight the importance of pretreatment for effective delignification and cellulose isolation. ChCl:urea treatment emerged as an efficient option against conventional methods, supporting future strategies for agricultural waste valorization. |
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