Co-hydrothermal carbonization (Co-HTC) of sewage sludge (SS) with wheat straw (WS) has emerged as a promising method for producing high quality biochar products through the utilization of low-cost biomass resources. The objective of this study was to investigate the physico-chemical properties of hydro-char derived from the Co-HTC treatment of the mixture of SS and WS at different Co-HTC temperatures (200, 240, and 280 °C). The research findings indicated that the inclusion of WS in the Co-HTC process positively influenced the properties of the hydro-char and higher Co-HTC temperatures enhanced this trend. It is revealed that the hydro-char produced at 280 °C exhibits the biggest surface area, abundance of micropore structures, and the highest electron accepting capacity (EAC = 0.4389 mol⁻/g_hydor-char). Moreover, when increasing the Co-HTC temperature from 200 to 240 °C, the higher degree of aromatization (H/C = 1.1170 (atomic ratio)) can be achieved, which correlates with the electron donating capacity (EDC = 0.7358 mol⁻/g_hydor-char). For the secondary dissolution of organic substances leaching from hydro-chars, the blending of SS and of WS can significantly enhance the content of aromatic protein II, with marginal impact on humic acid. Furthermore, the Co-HTC process proved effective in immobilizing heavy metals during the treatment. All of the improved properties facilitate the SW hydro-chars to be used as promoters in anerobic digestion system.

Graphical abstract

中文翻译：

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通过污水污泥和麦秆的共水热处理生产高质量水力炭：新特性

污水污泥（SS）与麦秆（WS）的共水热碳化（Co-HTC）已成为利用低成本生物质资源生产高质量生物炭产品的一种有前途的方法。本研究的目的是研究在不同 Co-HTC 温度（200、240 和 280 °C）下对 SS 和 WS 混合物进行 Co-HTC 处理而产生的水力炭的物理化学性质。研究结果表明，Co-HTC 过程中加入 WS 对水力炭的性能产生了积极影响，并且较高的 Co-HTC 温度增强了这一趋势。结果表明，280°C 生成的水炭具有最大的表面积、丰富的微孔结构和最高的电子接受能力（EAC = 0.4389 mol ⁻ /g _Hydror-char）。此外，当Co-HTC温度从200℃提高到240℃时，可以实现更高的芳构化程度（H/C = 1.1170（原子比）），这与给电子能力相关（EDC = 0.7358 mol ^- / g_氢炭）。对于水焦浸出有机物的二次溶解，SS和WS的混合可以显着提高芳香蛋白II的含量，而对腐殖酸的影响很小。此外，事实证明，Co-HTC 工艺在处理过程中可有效固定重金属。所有改进的特性都有助于 SW 氢炭在厌氧消化系统中用作促进剂。

图形概要