Recovering high value-added resources from waste activated sludge (WAS) is a potential way for the sustainable wastewater treatment. In this study, hydrothermal treatment at 180 °C was used to simultaneously improve sludge dewaterability and recover sludge organic matters (SOMs). The recovered SOMs were subsequently employed as precursors to prepare nitrogen-doped porous carbon nanosheets via a facile stepwise synthesis method. The as-prepared optimal carbon (AP-SOM₈₀₀) was characterized with an ultrahigh specific surface area (3473 m²/g), appropriate porosity (1.77 cm³/g), and abundant heteroatoms (1.47% N and 7.44% O). AP-SOM₈₀₀ exhibited a high specific capacitance (409 F/g at 0.25 A/g), low resistance (0.52 Ω), and superior cyclic stability (only 9.09% loss after 10,000 cycles) in 6 M KOH aqueous electrolyte. Furthermore, AP-SOM₈₀₀ demonstrated an extraordinary adsorption capacity (1528 mg/g for methyl orange (MO) and 1265 mg/g for tetracycline (TC)) that can be maintained (˃1200 mg/g) over a wide range of pH conditions. Specifically, 80.97% of MO and 66.67% of TC were rapidly absorbed through AP-SOM₈₀₀ within 10 min, and 90.27% of MO and 81.24% of TC were eventually removed from wastewater after 60 min. The adsorption processes fit closely with the pseudo-second-order kinetic (R² > 0.999) and Langmuir models (R² > 0.914), revealing that the adsorption processes were dominated by a monolayer chemical adsorption reaction. This study suggests that high value-added materials can be obtained from the WAS through improving and extending the traditional sludge treatment processes, which will enrich the technical options available for future sustainable sludge treatment and disposal.

从废弃活性污泥 (WAS) 中回收高附加值资源是可持续废水处理的潜在途径。在本研究中，采用 180 °C 水热处理同时提高污泥脱水能力和回收污泥有机物 (SOM)。回收的 SOM 随后用作前体，通过简单的逐步合成方法制备氮掺杂的多孔碳纳米片。所制备的最佳碳 (AP-SOM ₈₀₀ ) 具有超高比表面积 (3473 m ² /g)、适当的孔隙率 (1.77 cm ³ /g) 和丰富的杂原子 (1.47% N 和 7.44% O) . AP-SOM ₈₀₀在 6 M KOH 水性电解质中表现出高比电容（0.25 A/g 时为 409 F/g）、低电阻（0.52 Ω）和优异的循环稳定性（10,000 次循环后仅损失 9.09%）。此外，AP-SOM ₈₀₀表现出非凡的吸附能力（甲基橙 (MO) 为 1528 mg/g，四环素 (TC) 为 1265 mg/g），可以在很宽的 pH 范围内保持 (˃1200 mg/g)状况。具体而言，80.97% 的 MO 和 66.67% 的 TC在 10 分钟内被 AP-SOM ₈₀₀迅速吸收，60 分钟后最终从废水中去除了 90.27% 的 MO 和 81.24% 的 TC。吸附过程与拟二级动力学（R ²  > 0.999）和朗缪尔模型（R ² > 0.914)，表明吸附过程以单层化学吸附反应为主。本研究表明，通过改进和扩展传统的污泥处理工艺，可以从WAS中获得高附加值的材料，这将丰富未来可持续污泥处理和处置的技术选择。