微生物燃料电池组驱动的电吸附法对废水中铯的分离和机理研究

The rapid development of nuclear industry and the extensive application of nuclear technology have produced a large number of cesium-containing wastewater, from which the separation of cesium closely relates to the effect of treatment and disposal of the wastewater as well as environmental safety. Ferricyanide is ahighly efficient reagent forcesium removal. However, use of ferricyanide in the conventional adsorption way causing some problems such as difficulty in solid-liquid separation, comparatively high energy consumption and low regeneration efficiency of adsorbent. In the project, the electric adsorption (EA) is used to treat cesium-containing wastewater, in which the cathode is modified with copper ferricyanide (CuHCF).The EA is driven with microbial fuel cells (MFCs). The effects of the series number of MFCs, initial pH, time, coexisting ions, initial cesium concentration, thickness of CuHCF film and temperature on the separation performance are studied by single factor experiment. Moreover, theses parameters are optimized. The key parameters of the reversing electrode method used to regenerate CuHCF modified electrode are studied. The mechanism of separation of cesium with MFCs-EA is revealed by SEM-EDS, TEM, IR, XRD and XPS combined with experimental data..MFCs-EA is a new technology for treating cesium-containing wastewater. It has the advantages of zero external power, no solid-liquid separation and long service life of CuHCF. This study provides an innovative idea and method to deal with cesium-containing wastewater.

核工业的快速发展及核技术的广泛应用产生了大量含铯废水，铯分离事关废水的处理与处置效果及环境安全。铁氰化物是一种高效的除铯试剂，然而基于它的传统吸附法存在固液分离困难、能耗较高、吸附剂再生效率低等问题。本项目创新性提出了微生物燃料电池组（MFCs）驱动的电吸附（EA）法（MFCs-EA），以铁氰化铜（CuHCF）修饰EA装置中的阴极，处理含铯废水。采用单因素实验法研究MFC串联数量、初始pH、时间、共存离子、初始铯浓度、CuHCF膜厚度、温度等因素对分离性能的影响，并优化工艺参数；研究电极反接法再生CuHCF修饰电极关键参数；借助SEM-EDS、TEM、IR、XRD、XPS等表征手段并结合实验数据揭示MFCs-EA分离铯的机理。. MFCs-EA是一种处理含铯废水的新技术，具有零外界电能、无固液分离、CuHCF使用寿命长等优点。本研究将为处理含铯废水提供新思路、新方法。

铯高效分离技术对于含铯废水的处置和核能的健康可持续发展至关重要。微生物燃料电池(Microbial Fuel Cell，简称MFC)是利用微生物将废水中有机物所含的化学能直接转化为电能的装置。在处理废水的同时产生了电能，在环境保护与节能方面具有重要意义，将该电能成功应用于含铯废水的处理，将扩大MFC在废水处理领域中的应用范围。. 主要研究内容：1 CuHCF修饰电极的制备及微生物燃料电池（MFC）驱动的电吸附（MEA）系统启动；2 CuHCF 膜的表征；3 CuHCF膜对电极电化学性能的影响；4 Cs吸附与电极再生；5 MEA中Cs分离对MFC性能的影响。. 电子扫描电镜（SEM）、能谱仪（EDS）、X射线红外光谱仪（XRD）证实了CuHCF 膜对Cs的有效吸附；循环伏安曲线证实 CuHCF修饰后出现了一强一弱两对氧化还原峰；MEA系统中Cs吸附是石墨片、CuHCF膜和电吸附等多方面因素综合作用的结果；MFC在连接电吸附装置后，其输出电压有少量上升，输出功率密度和库伦效率显著下降，COD去除率差别不大。. 本项目研究结果表明，MEA系统可用于废水中Cs的分离，其分离效果和速度受多方面因素的影响，但主要控制因素是电吸附过程。采用电极反接法能够达到再生的目的，但由于MFC高内阻和低产电效率，使得MEA系统中电极再生效率、MFC输出电压、MFC功率密度和库伦效率等均较低。后期研究工作可能从降低MFC内阻及提高MFC产电效率两方面入手。