磷酸铵镁氯化分解机理及其产物循环沉氨性能研究

Due to the increasingly serious problem of the water ammonium nitrogen pullution in China, it is significant to develop high cost-effictive technologies for ammonia removal. Struvite precipitation is a simple and effective technology for ammonia removal, but the high cost of wastewater treatment still seriously restricts its practical application. Recycling the struvite pylolysate could effectively reduce the cost of ammonia removal. However, the present method of decomposing struvite easily produces invalid product, resulting in a decrease in the removal of ammonia. Aimed at the problem, the project tries to find another way and proposes a new idea concerning the decomposition of struvite by breakpoint chlorination. The main objectives of this project are: (i) to investigate the efficiency and mechanism of decomposing struvite by breakpoint chlorination; (ii) to understand the change process of decomposition product of struvite, the performance of ammonia removal reusing the decomposition product, and the ammonia removal efficiency of multiple recycling; (iii) to elucidate the change relationship between the multiple recycling period of decomposition product and the composition of the obtained precipitates. Consequently, this project will establish the method of struvite multiple recycling, and also provide the theoretical basis and the technological support for the effctive treatment of ammonium nitrogen wastewater and the further development of struvite recycling technique.

近年来我国水体氨氮污染状况日益严峻，迫切需要开发高效的氨氮废水治理技术。磷酸铵镁沉淀是一种高效、简便的除氨技术，但其高废水治理成本严重制约了该技术的推广应用。循环利用磷酸铵镁分解产物是降低其处理成本的重要途径，然而现有磷酸铵镁热解方法存在易产生无效产物，导致氨氮去除效率降低的问题。针对该问题，本项目另辟蹊径，提出折点氯化分解磷酸铵镁新思路。探究磷酸铵镁氯化分解效率和机理，揭示磷酸铵镁氯化分解产物变化过程；考察分解产物沉氨性能和多次循环利用效果，阐明分解产物多次循环利用周期与反应生成沉淀物组分之间的变化关系，初步构建磷酸铵镁氯化分解产物多次循环利用方法，从而为氨氮废水的高效处理和磷酸铵镁循环利用技术的进一步发展提供理论基础和技术支持。

近年来我国水体氨氮污染状况日益严峻，迫切需要开发高效的氨氮废水治理技术。磷酸铵镁沉淀是一种高效、简便的除氨技术，但其高废水治理成本严重制约了该技术的推广应用。循环利用磷酸铵镁分解产物是降低其处理成本的重要途径，然而现有磷酸铵镁热解方法存在易产生无效产物，导致氨氮去除效率降低的问题。针对该问题，本项目另辟蹊径，提出折点氯化分解磷酸铵镁新思路, 为氨氮废水的高效处理和磷酸铵镁循环利用技术的进一步发展提供理论基础和技术支持。项目主要研究内容如下：磷酸铵镁折点氯化脱氨效率研究，磷酸铵镁折点氯化分解机理研究，磷酸铵镁氯化分解产物沉氨性能研究及多次循环沉氨技术性能评价。针对上述研究内容取得了如下重要结果：1） 磷酸铵镁在常温溶液体系中氯化分解是完全可行的，其分解率可达100%， 主要活性产物为固态的磷酸氢镁和离子态的磷酸盐和镁盐，无其他非活性副产物；2）利用磷酸铵镁氯化分解产物循环除铵可实现与使用新鲜磷和镁试剂相同的除铵效果，连续循环利用5次，其氨氮去除效率均保持在90%左右。该项目的顺利实施为磷酸铵镁循环利用提出了一种全新的思路，并为相关研究提供了理论基础和技术支持，可为后续研究提供参考和借鉴。该项目研究成果具有较好的应用前景，可应用于低浓度氨氮废水（小于500 mg/L）的实际处理，并能有效降低现有氨氮废水处理工程投资额。