Producing Hydrochar from Cotton Linter Black Liquor and Performing Alkali Recovery

Nan Lu, Guihua Yang, Jiachuan Chen, Qiang Wang, Lihua Pei, Lucian A. Lucia


Holistic utilization of cotton linter black liquor is crucial from both economic and environmental standpoints. For this purpose, the hydrothermal conversion process was selected to produce hydrochar from organic materials dissolved in black liquor. Fourier transform infrared spectroscopy (FT-IR) analysis showed that there were no significant functional changes in the hydrochar compared with black liquor solid (BLS) at different preserving temperatures. However, a C-O bond was ruptured by the hydrothermal carbonization. Thermogravimetric analysis also showed that the thermal stability of the hydrochar was increased. The higher heating value (HHV) of hydrochar at the different preserving temperature from 200 °C to 280 °C was higher than BLS, reaching a maximum at 200 °C. On the other hand, the alkali from the liquor production of hydrothermal carbonization was recovered by causticization; the highest causticizing efficiency (CE) was 45.2%. The recovered liquor alkali can be used in pulping or pretreatment strategies.


Cotton linter pulp; Black liquor; Hydrothermal carbonization; Hydrochar; Alkali recovery

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Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022,; Lucian A. Lucia, (919) 515-7707, URLs:; ISSN: 1930-2126