Sustainable hydrochar-based catalysts: supporting Ag and Fe nanoparticles on hydrochar using the concéntrate derived from the hydrothermal treatment of Jatropha fruit husk
This work presents the development of sustainable catalysts based on hydrochar, obtained through the hydrothermal carbonization of lignocellulosic residues such as rice husk, palm kernel shell, brewer’s spent grain, and cocoa shell. The biomass samples were treated at 250 °C for 60 minutes, producin...
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| Format: | masterThesis |
| Publicat: |
2025
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| Matèries: | |
| Accés en línia: | https://repositorio.yachaytech.edu.ec/handle/123456789/1013 |
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Afegir etiqueta | Sumari: | This work presents the development of sustainable catalysts based on hydrochar, obtained through the hydrothermal carbonization of lignocellulosic residues such as rice husk, palm kernel shell, brewer’s spent grain, and cocoa shell. The biomass samples were treated at 250 °C for 60 minutes, producing a carbon-rich solid (hydrochar) and a liquid phase rich in organic compounds (commonly known as spent liquor). Once concentrated, the spent liquor was used as a natural reducing agent to synthesize iron and silver nanoparticles directly on the hydrochar surface. The metal impregnation was carried out ex situ and assisted by LED light. To evaluate their catalytic performance, two test reactions were used: the reduction of methyl orange with silver-based catalysts, and the oxidation of methylene blue with iron-based ones in a Fenton-like reactions. All catalysts demonstrated higher efficiency compared to their non-impregnated controls. Among them, hydrochars derived from brewer’s spent grain and palm kernel shell achieved removals of 95.3% and 93.1% of methyl orange, respectively. Regarding methylene blue, the hydrochar from rice husk reached a removal efficiency of 87.3%. Both reactions followed pseudo-first-order kinetics, with correlation coefficients exceeding 0.98. Characterization techniques including XRD, FTIR, and SEM confirmed the effective impregnation of metallic nanoparticles, as well as the presence of functionalized and porous surfaces that contributed to the enhanced catalytic performance. Overall, this study proposes a sustainable approach for valorizing agro-industrial residues and generating effective materials for water treatment applications, aligning with the principles of green chemistry and the circular economy. |
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