Tannic acid (TA) aided hydrothermal treatment (HT) can decrease effective HT temperatures for sludge deep dewatering by chelator protein, but faces notable and economic challenges including the failure to remove antibiotics and the limited protein binding capacity. Herein, hydrothermally activated TA (in situ TA + HT) was conducted to simultaneously improve sludge dewaterability and antibiotic (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) removal. Compared to traditional HT and HT + TA treatment, the in-situ TA + HT process could further strengthen the TA-aided HT efficacy in enhancing sludge and reducing the protein content in the filtrate simultaneously; in which the optimal HT temperature for the dewatering of the sludge was reduced from 180 °C to 140 °C. Furthermore, the total removal efficiency of target antibiotics was achieved at more than 71.0–94.7% for TC and OTC, and 72.0–84.8% for NOR and OFL. The highly reactive species (·OH) generation and the electron transfer efficiency from the hydrothermal-activated TA process were responsible for the elimination of antibiotics and promoted the hydrolyzation and mineralization of HMW protein in sludge during the HT process. Meanwhile, the degradation of HMW proteins and the destruction of the secondary structure of these proteins resulted in improved hydrophobicity and dewaterability of sludge. Hydrothermally activated TA induces covalent binding with the protein. As a result, hydrothermal-activated TA could promote the removal of antibiotics and proteinaceous compounds from the sludge samples, improving the hydrophobicity of sludge and releasing bound water from the sludge flocs during HT. Finally, the cost of hydrothermal-activated TA was 66.51% lower than that of thermal drying treatment. This study not only proposed an effective method to improve traditional HT for sludge thermal dry-free treatment, but also provided new information on the catalysis roles of polyphenols in the hydrothermal conversion of sludge.

中文翻译：

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水热活化单宁酸（TA）同时深度脱水和去除抗生素的机理见解

单宁酸（TA）辅助水热处理（HT）可以降低螯合蛋白对污泥深度脱水的有效高温温度，但面临着显着的经济挑战，包括无法去除抗生素和有限的蛋白质结合能力。在此，进行水热活化TA（原位TA + HT）以同时提高污泥脱水性和抗生素（四环素（TC）、土霉素（OTC）、诺氟沙星（NOR）、氧氟沙星（OFL））去除率。与传统HT和HT+TA处理相比，原位TA+HT工艺可以进一步增强TA辅助HT的效果，同时增强污泥并降低滤液中的蛋白质含量；其中污泥脱水的最佳高温温度从 180 °C 降低至 140 °C。此外，对于TC和OTC，目标抗生素的总去除率达到71.0-94.7%以上，对于NOR和OFL，目标抗生素的总去除率达到72.0-84.8%。水热激活TA过程中产生的高活性物质（·OH）和电子传递效率有助于消除抗生素，并促进HT过程中污泥中HMW蛋白质的水解和矿化。同时，HMW蛋白的降解和这些蛋白二级结构的破坏导致污泥的疏水性和脱水性提高。水热活化的 TA 诱导与蛋白质的共价结合。因此，水热活化的 TA 可以促进污泥样品中抗生素和蛋白质化合物的去除，提高污泥的疏水性，并在 HT 过程中释放污泥絮体中的结合水。最终，水热活化TA的成本比热干燥处理降低了66.51%。该研究不仅提出了改进传统高温污泥热免干处理的有效方法，而且为多酚在污泥水热转化中的催化作用提供了新的信息。