Aiming at the sustainable management of high-moisture Chinese medicine residues (CMR), an alternative way integrating hydrothermal carbonization (HTC), humic acids (HAs) extraction and combustion of remained hydrochar has been proposed in this study. Effect of HTC temperature, HTC duration, and feedwater pH on the mass yield and properties of HAs was examined. The associated formation mechanism of HAs during HTC was proposed. The combustion performance of remained hydrochar after HAs extraction was evaluated. Results show that the positive correlation between hydrochar yield and HAs yield is observed. According to three-dimensional excitation emission matrix (3D EEM) fluorescence intensity, the best quality of HAs is achieved with a yield of 8.17 % at feedwater pH of 13 and HTC temperature of 200 °C. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses show abundant aromatic and aliphatic structure as well as oxygenated functional groups in HAs, which is like commercial HAs (HA-C). Besides, in terms of comprehensive combustion index (), HTC can improve the combustion performance of CMR, while it becomes a bit worse after HAs extraction. Higher weighted mean apparent activation energy (m) of hydrochar indicating its highly thermal stability. HAs extraction reduces m and of remained hydrochar. However, it can be regarded a potential renewable energy. This work confirms a more sustainable alternative way for CMR comprehensive utilization in near future.

中文翻译：

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中药渣水热炭化：腐植酸的形成及提取氢炭的燃烧性能

针对高水分中药残渣（CMR）的可持续管理，本研究提出了一种集水热碳化（HTC）、腐植酸（HAs）提取和剩余水炭燃烧为一体的替代方法。研究了 HTC 温度、HTC 持续时间和给水 pH 值对 HA 质量产量和性质的影响。提出了 HTC 期间 HA 的相关形成机制。对HAs提取后剩余的氢炭的燃烧性能进行了评估。结果表明，水炭产率与HAs产率之间存在正相关关系。根据三维激发发射矩阵（3D EEM）荧光强度，在给水 pH 值为 13、HTC 温度为 200 °C 时，HA 的质量达到最佳，产率为 8.17%。傅里叶变换红外光谱和X射线光电子能谱分析显示HA中含有丰富的芳香族和脂肪族结构以及含氧官能团，这与商业HA（HA-C）类似。另外，在综合燃烧指数（）方面，HTC可以改善CMR的燃烧性能，而HAs提取后则变得稍差。水炭的较高加权平均表观活化能（m）表明其具有较高的热稳定性。 HAs 提取减少了剩余氢炭的 m 和 。然而，它可以被视为一种潜在的可再生能源。这项工作证实了在不久的将来 CMR 综合利用的一种更可持续的替代方式。