| Abstrakt: |
Traditional Chinese medicine (TCM) played an important role in the fight against the COVID-19 virus in the past three years. The production of TCM resulted in huge quantities of traditional Chinese medicine residues (TCMRs) in China. Hydrothermal treatment (HTT) is an appropriate method to convert the TCMRs to hydrochar and liquid phase products. This study investigated the effects of hydrothermal temperature (220–280 °C), reaction time (60–240 min), and solid–liquid ratio (1:5 to 1:15) on the HTT process. Hydrothermal temperature was found to have the most significant influence on HTT, followed by reaction time and solid–liquid ratio. The optimal condition for producing the hydrochar was determined at 260 °C, 180-min reaction time, and the solid–liquid ratio of 1:5, with an energy recovery efficiency of 59.46%. The carbon content and higher heating value (HHV) of hydrochar were 68.53% and 28.28 MJ/kg, respectively, which were greatly improved compared with TCMRs. In addition, the liquid phase products contained abundant dissolved organic chemicals including organic acids, aromatic compounds, and furans, which were considered to be valuable intermediate chemicals. These findings confirmed that HTT is promising to convert TCMRs into valuable products. [ABSTRACT FROM AUTHOR] |
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