Lin Wei, Liu Shuai, Zhang Shenghao, Li Mingtao, Gao Xiangpeng, Zhou Chunyang, Fan Fuqiang, Zhao Bikui
Guangdong-Hong Kong Joint Laboratory for Water Security, Beijing Normal University, Zhuhai 519087, China; Center for Water Research, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai 519087, China.
Guangdong-Hong Kong Joint Laboratory for Water Security, Beijing Normal University, Zhuhai 519087, China; Center for Water Research, Advanced Institute of Natural Sciences, Beijing Normal University, Zhuhai 519087, China; Guangdong Research Institute of Water Resources and Hydropower, Guangzhou 510635, China.
Int J Biol Macromol. 2025 May;309(Pt 1):142745. doi: 10.1016/j.ijbiomac.2025.142745. Epub 2025 Apr 1.
La-based nanoparticles encapsulated within a host matrix exhibit enhanced phosphate removal efficiency and improved stability compared to their bulk counterparts. The optimization of La-based adsorbents, balancing adsorption capacity and separation efficiency, is of great significance. In this study, we developed a three-dimensional layered skeleton network of La-modified graphene oxide/sodium alginate beads (La-GO/SA) by uniformly embedding La(OH)₃. Original GO maintained a high specific surface area (2630 m/g), which boosted the surface area, electrical crosslinking, and affinity towards oxygen-donor compounds of La-GO/SA. The crosslinked hydrogel exhibited enhanced mesoporous and microporous structures, as confirmed by scanning electron microscopy (SEM) and surface structural analyses. Batch experiments demonstrated that La-GO/SA achieved stable phosphate removal (>80 %) across a broad pH range of 3.0-10.0, with a maximum phosphate uptake of 34.8 mg/g at pH 4.0. Notably, La-GO/SA maintained high selectivity for phosphate even in the presence of competing anions such as Cl, HCO, SO, and NO. The experimental data were well-fitted to Freundlich and pseudo-second-order models, indicating a multilayer chemisorption mechanism. Additionally, multi-instrument characterization analysis elucidated the phosphate removal mechanisms, including electrostatic interactions, surface precipitation, ligand exchange, and Lewis acid-base interactions. The La-GO/SA hydrogel provided attachment sites for LaPO precipitates, which contributed to a decrease in pore volume after adsorption. Our research on the synthesis, properties, and adsorption mechanisms of La-GO/SA hydrogel laid a scientific foundation for practical phosphate immobilization and recycling applications.
与块状材料相比，包裹在主体基质中的镧基纳米颗粒表现出更高的磷酸盐去除效率和更好的稳定性。优化镧基吸附剂，平衡吸附容量和分离效率，具有重要意义。在本研究中，我们通过均匀嵌入La(OH)₃，开发了一种三维层状骨架网络结构的镧改性氧化石墨烯/海藻酸钠珠（La-GO/SA）。原始的氧化石墨烯保持了较高的比表面积（2630 m/g），这提高了La-GO/SA的表面积、电交联以及对供氧化合物的亲和力。扫描电子显微镜（SEM）和表面结构分析证实，交联水凝胶具有增强的中孔和微孔结构。批量实验表明，La-GO/SA在3.0 - 10.0的宽pH范围内实现了稳定的磷酸盐去除（>80%），在pH 4.0时最大磷酸盐吸附量为34.8 mg/g。值得注意的是，即使在存在Cl、HCO、SO和NO等竞争阴离子的情况下，La-GO/SA对磷酸盐仍保持高选择性。实验数据与Freundlich模型和准二级模型拟合良好，表明存在多层化学吸附机制。此外，多仪器表征分析阐明了磷酸盐去除机制，包括静电相互作用、表面沉淀、配体交换和路易斯酸碱相互作用。La-GO/SA水凝胶为LaPO沉淀提供了附着位点，这导致吸附后孔体积减小。我们对La-GO/SA水凝胶的合成、性质和吸附机制的研究为实际的磷酸盐固定和回收应用奠定了科学基础。
