普鲁士蓝类似物和磷灰石纳米复合高效铯离子吸附剂的开发和穆斯堡尔谱学研究

It is an important and urgent issue to research and develop advanced treatment and purification technology for radioactive waste water with 137Cs. By carefully investigating the possible routes of Cs+ fixing into the structures of Prussian blue-based (PBA) and apatite-based (AP) sorbents, the new Cs+ sorbents of a series of soluble and insoluble hexacyanocobaltate(III) iron(II), hydroxyapatite and fluorapatite will be separately synthesized by co-precipitation, ion-exchange and intercalation methods. Based on the characterization results of regular and in-situ 57Fe M?ssbauer spectroscopy, Cs LIII edge X-ray absorption fine structure spectroscopy, the Rietveld structural refinement and other various advanced techniques for the prepared materials, the relationships will be made clear between their Cs+ sorption capabilities and their various physical and chemical properties, the reasonable Cs+ sorption mechanism will be explored systematically. Beyond these above mentioned researches, the PBA and AP novel nanocomposite sorbents with different mole radio and architectures will be developed by using the established methods of chemical precipitation and simulated body fluid, their chemical compositions, structures, Cs+ sorption properties and mechanisms will be further studied. The Cs+ sorption properties can be improved and their mechanical stabilities can be enhanced by compositing the selected high efficient PBA and AP sorbents with defined composition and structure. Through the deep understanding of the structure-activity relationships and mechanisms of PBA, AP and their composited sorbents, we aim to develop novel nanocomposited Cs+ sorbent with stable composition and structure, provide a theoretical basis and help for their industrial applications. Advantage of this project is realized the monitor of the real-time status of Cs+ in and out of the sorbent structures by the utilization of the in-situ spectroscopic characterizations and a variety of conventional techniques. The project is multidisciplinary, its goal is to design novel kinds of highly efficient sorbent materials for removal radioactive Cs+ pollutants from waste aqueous solution, furthermore, exploring out of their sorption mechanisms.

本项目在考虑Cs+进入普鲁士蓝基（PBA）和磷灰石基（AP）吸附剂结构的各种路径的基础上，利用共沉淀、离子交换和插入法分别合成六氰基钴(III)酸铁(II)及羟基磷灰石和氟化磷灰石Cs+吸附剂。通过穆谱、结构精修、XAFS等技术对所合成材料进行表征，明确它们的Cs+吸附性能与其物理化学性质的关系，给出合理的Cs+吸附机理。在此基础上，利用化学沉淀和模拟体液法确立PBA和AP纳米复合吸附剂的制备方法，进一步研究它们的组成、结构、Cs+吸附性能和机理。PBA和AP复合可进一步提高它们的Cs+吸附性能，增强其机械稳定性。在深入探讨PBA、AP及二者复合吸附剂的构效关系和机理的基础上，开发出组成和结构稳定的Cs+吸附新材料，为其工业化应用提供依据和帮助。本项目的优势在于利用原位光谱学及各种常规表征来研究吸附剂结构中Cs+进出的实时状态。本项目多学科交融，目标是设计高效Cs+吸附材料，解明其机理。

围绕既定的研究主题，本项目主要在以下几方面取得了系列性进展：1）以Fe-Co普鲁士蓝类似物（PBA）为研究对象，利用锌离子掺杂和温度调变的方法实现了对其组成和形貌的精细调控，系统考察了纳米结构Fe-Co PBA及其含锌衍生物在铯离子反应吸附及作为芬顿催化剂在双酚A降解中的性能。2）系统考察了普鲁士蓝类似物及其衍生合成过渡金属氮（氧）化物在催化类芬顿反应和电化学中的应用，以穆斯堡尔谱为主要手段，对其催化机理及过渡金属阳离子占位与活性的构效关系进行了深入探讨。3）采用不同方法制备了多种纳米结构铁基复合催化剂，以穆斯堡尔谱为主要手段对其结构进行了表征，研究了其催化活化过一硫酸盐降解有机污染物的性能和反应机理，通过特殊形貌结构的设计改性，可进一步提高催化剂的活性和反应稳定性。4）首次发现金纳米颗粒与羟基磷灰石（HAP）之间在高温氧化气氛下发生的金属载体强相互作用（O-SMSI），Au和HAP之间的O-SMSI不仅能够有效提升Au纳米颗粒的高温抗烧结性能，且能够提高催化剂在液相反应中的选择性和重复使用性能；进一步研究发现Au与HAP之间的O-SMSI效应具有普适性，可以扩展到其它磷酸盐担载的纳米金催化剂体系。5）首次发现并确认了Au纳米颗粒与TiO2之间的经典SMSI效应，经过系列原位表征发现该SMSI效应具有与TiO2担载的铂族金属体系的经典SMSI效应完全一致的特征，该SMSI效应也可以扩展到其它氧化物负载的金催化剂和TiO2负载的其它IB族金属催化剂。6）首次发现并确认了铂族金属（PGMs，Pd和Pt）与HAP之间的O-SMSI效应，表明PGMs与不同载体在不同环境下可形成不同种类的SMSI效应，使得我们可以根据催化剂的实际应用环境选择载体类型，制备合适的SMSI效应稳定的负载型催化剂。7）利用异相复合、离子掺杂以及将异相复合和离子掺杂相结合的改性方法，制备了不同晶相组成的TiO2，Sn-Fe共掺杂TiO2，Sn-N共掺杂TiO2以及碳酸盐物种自掺杂的异相复合TiO2，以穆斯堡尔谱为主要手段对其结构进行了表征，同时研究了它们在光催化降解有机染料反应中的光催化性能。