纳米水合氧化镧除磷复合吸附剂的再生特性与潜在机制研究

Efficient selective separation of phosphate from wastewater is of great significance for achieving polishing treatment and recovery of phosphorus. Lanthanum based nanocomposites adsorbents are promising candidate for real application, as they integrate the high phosphate affinity of lanthanum (hydro)oxides and the attractive performance of the host material. However, current lanthanum based adsorbents often face difficulties in efficient and stable regeneration, which dramatically undermined their cost-effectiveness and possibility for application. In our previous studies, we first discovered that hydrous lanthanum oxides (HLO) nanocomposites adsorbent could be regenerated under mild condition, but the regeneration mechanism was not clearly elucidated, the regeneration methods for practical application should be further optimized. In this project, dispersed and immobilized nano-HLO adsorbents are to be fabricated. Studies will be conducted using both adsorbents, including phosphate removal performance and sorbents regenerative characteristics, the influence of solution chemistry on phosphate adsorption and material regeneration and the underlying mechanisms of La-P interactions during adsorption and regeneration. Through careful analysis and comparison, the HLO-LaPO4 crystal transformation characteristics and mechanism under confinement will be elucidated. Then, the methods and conditions for regeneration will be optimized based on the above findings. Lastly, the fixed-bed adsorption-regeneration cyclic runs will be conducted to evaluate the column phosphate removal performance and phosphorous recovery potential of the synthesized adsorbents. This research project is expected to offer solutions for regeneration problems of La nanocomposites adsorbents, while providing theoretical basis and technical guidance for advanced treatment and recovery of phosphorus from wastewaters using lanthanum based nanocomposites adsorbents.

污水中磷酸盐的选择性分离是实现磷深度处理与回收的关键。负载型纳米镧氧化物吸附剂有机结合了镧氧化物突出的除磷能力与大颗粒载体的可操作性，但仍普遍存在难以再生与重复利用的技术瓶颈。前期研究发现负载型纳米水合氧化镧除磷后可在温和条件下实现再生，但再生微观过程与机制仍不清晰，实际水处理过程中再生技术的开发缺乏理论指导。本项目拟系统探究分散型和负载型纳米水合氧化镧深度除磷和再生的基本特性；探索纳米水合氧化镧与磷酸盐结合形成磷酸镧晶体及解裂逆转换的微观机制；在此基础上，阐明材料深度除磷及再生过程中纳米水合氧化镧-磷酸镧晶态转换规律和机制，优化复合吸附剂再生技术，进而系统评估复合材料固定床深度除磷-循环再生性能及磷回收潜力，为突破镧氧化物纳米复合吸附剂的再生瓶颈、实现其在污水深度除磷系统中的应用提供理论与技术参考。

污水中磷酸盐的选择性分离是实现磷深度处理与回收的关键。负载型纳米镧氧化物吸附剂有机结合了镧氧化物突出的除磷能力与大颗粒载体的可操作性，但仍普遍存在难以再生与重复利用的技术瓶颈。前期研究开发的可再生负载型纳米水合氧化镧的再生微观过程与机制仍不清晰，实际水处理过程中再生技术的开发缺乏理论指导。本项目首先通过结构调控技术并利用“前驱体导入-纳米网孔成核”制备方法研制了不同晶体结构的分散型和负载型水合氧化镧材料，通过光谱学手段表征和计算得到了上述材料的表面构型。通过分析材料深度净污和再生效果与其表面功能基的相关性，阐明了上述材料的构效关系。在此基础上,项目探索了在模拟水和真实污水情况下，分散型和负载型水合氧化镧长期除磷和再生过程中的La-P结合方式的演变规律，通过分析分散体系和限域体系下La-P结合物晶体结构、化学形态和P-H质子位移，揭示了限域体系对强化La-P反应和逆反应的有益作用。与此同时，项目还探索了水中共存基质中Ca2+和有机质对铁系和镧系复合纳米材料深度除磷多批次吸附-再生的影响规律和机制，揭示了长期运行过程中污染物-纳米颗粒-Ca2+/有机物体系的结构与组成演化规律。本项目还开发了系列新系镧系/锆系复合纳米材料，并对其深度除磷除氟性能和机制进行了研究。本项目优化了镧系复合纳米材料生产过程，实现了规模化生产。通过利用纳米限域效应原理，成功解决了镧系材料难以再生的技术难题。在此基础上开发成功基于镧系复合纳米材料的深度除磷技术，并试制了基于上述除磷技术的集成深度除磷中试装置，并在加拿大、香港等地针对真实地表水进行了现场中试研究，验证了项目开发的材料和技术在长期运行过程中的除磷性能和稳定性。充分表明了项目了开发材料和技术的应用潜力。项目研究成果有望为新型深度除磷材料和技术的开发和实际应用提供科学基础和技术指导。. 围绕上述研究，项目在Environ. Sci. Technol.等SCI期刊发表论文8篇，申请国家发明专利4项，培养研究生4名，并进行了中试研究。