Material architecture indicators.

A novel granular waterworks-derived sludge composite (GT La-WDS) was synthesized via green and low-carbon hydrothermal carbonization combined with a calcination-free granulation method, demonstrating exceptional phosphate adsorption performance and potential as constructed wetland filler. Comprehensive characterization (SEM, XRF, BET, FTIR, XRD) revealed its hierarchical porous morphology, chemical composition, and hydroxyl/ligand-functionalized surfaces. Optimal phosphate adsorption capacity (20.11 mg/g) was achieved at pH 4, with adsorption mechanisms dominated by ligand substitution and formation of inner-sphere complexes, as supported by quasi-second-order kinetic modeling and Freundlich isotherm conformity. Dynamic column tests showed prolonged breakthrough (from 168 h to 432 h) and exhaustion times (from 588 h to 2088 h) with increasing bed heights (10 cm to 30 cm), achieving total adsorption capacities of 9.276 mg/g. Effluent phosphate concentrations remained below 0.5 mg/L (Chinese National Effluent Standard Class 1B) for 588 h, with sustained removal efficiency over 2088 h, indicating remarkable longevity. This sludge-derived composite presents a cost-effective solution for phosphorus sequestration, offering dual benefits of eutrophication mitigation and sustainable sludge valorization, with particular relevance to low-carbon constructed wetland systems.

新型颗粒状水厂污泥复合材料（GT La-WDS）通过绿色低碳水热炭化结合免煅烧造粒法合成，展现出优异的磷酸盐吸附性能，具备作为人工湿地填料的应用潜力。采用扫描电子显微镜（SEM）、X射线荧光光谱（XRF）、比表面积分析法（BET）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）开展的综合表征结果，揭示了该材料的分级多孔形貌、化学组成以及羟基/配体功能化表面。在pH为4时，其磷酸盐吸附容量达到最优值20.11 mg/g，吸附机制以配体取代和内球络合物形成为主导，准二级动力学模型拟合与弗罗因德利希（Freundlich）等温线模型符合性验证了该机制。动态柱试验结果表明，随着填料床高度从10 cm增至30 cm，穿透时间从168 h延长至432 h，耗尽时间从588 h延长至2088 h，总吸附容量可达9.276 mg/g。出水磷酸盐浓度在588 h内持续低于0.5 mg/L（符合中国《污水综合排放标准》一级B类），且在2088 h内仍保持稳定的去除效率，展现出优异的使用寿命。该污泥基复合材料为磷固定提供了经济高效的解决方案，兼具缓解水体富营养化与实现污泥可持续资源化的双重效益，尤其适用于低碳型人工湿地系统。