Synergistic valorization of sewage sludge and lignin-rich lignocellulose via activated carbon-mediated Co-HTC: Enhancing hydrochar quality and its pyrolysis performance
This study provides mechanistic insights into the role of rice-husk-derived activated carbon (AC:Y, 5–25 wt%) during co-hydrothermal carbonization (co-HTC) of sewage sludge (SS) and lignin-rich lignocellulose (LC:X, 5–25 wt%) at 200 ◦C for 60 min, followed by pyrolysis of the resulting hydrochars (H...
| Authors: | , , , , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2026 |
| Country: | España |
| Institution: | Universidad de Sevilla (US) |
| Repository: | idUS. Depósito de Investigación de la Universidad de Sevilla |
| OAI Identifier: | oai:dnet:idus________::03a57dc1afc527fa40b8ade7d42b92f3 |
| Online Access: | https://hdl.handle.net/11441/186259 https://doi.org/10.1016/j.scca.2026.100188 |
| Access Level: | Open access |
| Keyword: | Activated carbon Co-hydrothermal carbonization Hydrochar Lignocellulose Pyrolysis Sewage sludge Syngas production |
| Summary: | This study provides mechanistic insights into the role of rice-husk-derived activated carbon (AC:Y, 5–25 wt%) during co-hydrothermal carbonization (co-HTC) of sewage sludge (SS) and lignin-rich lignocellulose (LC:X, 5–25 wt%) at 200 ◦C for 60 min, followed by pyrolysis of the resulting hydrochars (HCs) between 500 ◦C-900 ◦C. Comprehensive characterization (FTIR, Raman, XPS, BET, SEM, TGA) of HC revealed that Y significantly enhanced its fuel quality and structural re-ordering. The optimized sample (SS-5X-5Y) showed higher carbon content (47.51 ± 0.092 %) and higher heating value (HHV:18.67 ± 0.038 MJ⋅kg⁻¹), and SS-25X-25Y demonstrated reduced ash content (24.60 ± 0.067 %) compared to SS-X alone. FTIR confirmed the presence of C=O (~1700 cm⁻¹), aromatic C=C (~1590 cm⁻¹), C–O (1200–1050 cm⁻¹), and S=O (~1100–1050 cm⁻¹) functionalities. Raman (ID/IG ↓ from 0.60 to 0.47) and XPS (C–C up to 78 %) indicated enhanced aromatic condensation and deoxygenation induced by Y. Pyrolytic products indicated that Y-mediated HCs promoted syngas-rich products, achieving 33–35 vol% H₂ and 45–49 vol% CO at 900 ◦C. This study establishes a robust framework for future investigation, particularly long-term combustion/gasification evaluations and detailed leaching behavior analysis, which will further validate the environmental stability, operational reliability, and broader techno-economic potential of Y-mediated HCs. |
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