Qi Rao, Chen Shiyu, Wang Chonghao, Fan Xiuyuan, Wang Yafen
School of Environmental Studies, China University of Geosciences, Wuhan, 430078, PR China.
School of Environmental Studies, China University of Geosciences, Wuhan, 430078, PR China; MOE Key Laboratory of Groundwater Quality and Health, School of Environmental Studies, China University of Geosciences, Wuhan, 430078, PR China.
Environ Res. 2025 Jul 23;285(Pt 2):122420. doi: 10.1016/j.envres.2025.122420.
This study systematically evaluates phosphorus (P) adsorption and capping performance of core-shell ZnAlLa-NO-layered double hydroxides (LDHs)@quartz sand (QS) materials, focusing on the influence of particle size and biofilm pre-coating in their practical application for lake management. In 24 h adsorption experiments (adsorbent dosage: 1.0 g/L), 200 mesh LDHs@QS (QSL) exhibited a significantly higher P adsorption capacity (Q, 9.58 mg/g) than 20 mesh QSL (2.31 mg/g), as derived from the Langmuir model. Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that phosphate adsorption by LDHs involved inner-sphere complexation, ion exchange, and chemical adsorption. In a 14 d capping experiment, P release reduction was primarily determined by material type rather than particle size or initial sediment P levels. Specifically, LDH-based materials, with or without biofilm (QSLB: 88.3% and QSL: 91.3%), significantly outperformed the original QS (70.4%). Total P flux even reversed to negative values, particularly in the QSLB treatments, which exhibited the lowest proportion of loosely bound P (1.8%), compared to 3.5% for QSL and 13.1% for QS. Principal component analysis revealed that QSLB had minimal disturbance to overlying water and sediment properties relative to the blank control, highlighting its environmental compatibility. Moreover, nitrate-intercalated LDHs functioned as a slow-release oxidant, enhancing the oxidation-reduction potential (ORP) of overlying water, demonstrating their multifunctional potential for long-term internal P control. This study lays a groundwork for customizing core-shell LDH-based capping materials for efficient and environmentally friendly remediation of eutrophic water bodies.
本研究系统评估了核壳结构的ZnAlLa-NO层状双氢氧化物（LDHs）@石英砂（QS）材料对磷（P）的吸附和覆盖性能，重点关注了粒径和生物膜预涂层对其在湖泊治理实际应用中的影响。在24小时吸附实验（吸附剂用量：1.0 g/L）中，根据朗缪尔模型，200目LDHs@QS（QSL）的磷吸附容量（Q，9.58 mg/g）显著高于20目QSL（2.31 mg/g）。傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）证实，LDHs对磷酸盐的吸附涉及内层络合、离子交换和化学吸附。在14天的覆盖实验中，磷释放减少主要取决于材料类型，而非粒径或初始沉积物磷水平。具体而言，基于LDH的材料，无论有无生物膜（QSLB：88.3%和QSL：91.3%），均显著优于原始QS（70.4%）。总磷通量甚至转为负值，尤其是在QSLB处理中，其松散结合磷的比例最低（1.8%），而QSL为3.5%，QS为13.1%。主成分分析表明，相对于空白对照，QSLB对上覆水和沉积物性质的干扰最小，突出了其环境兼容性。此外，硝酸根插层的LDHs作为缓释氧化剂，提高了上覆水的氧化还原电位（ORP），证明了其在长期内源性磷控制方面的多功能潜力。本研究为定制基于核壳LDH的覆盖材料以高效、环保地修复富营养水体奠定了基础。
