粉煤灰衍生介孔硅钙材料吸附去除Co（Ⅱ）及放射性过渡金属离子性能研究  

Removal of Co （Ⅱ） and Radioactive Transition Metal Ions by Adsorption on Fly Ash-Derived Mesoporous Calcium-Silicate Material

作　　者：雷雪飞[1] 祁光霞 孙应龙[1] 李磊[1] 袁超[1] 王毅[1] 孙俊民 

机构地区：[1]清华大学环境学院环境工程系核环境工程教研所,北京100084 [2]国家能源高铝煤炭资源开发利用重点实验室,内蒙古呼和浩特010050

出　　处：《核化学与放射化学》2014年第B12期13-20,共8页Journal of Nuclear and Radiochemistry

基　　金：清华大学人才支持基金项目

摘　　要：针对含低水平放射性过渡金属离子废水的处理需求，本工作以Co（Ⅱ）为代表，研究了粉煤灰衍生介孔硅钙材料对Co（Ⅱ）的吸附去除性能。研究结果表明，高铝粉煤灰“预脱硅一碱石灰烧结提铝”工艺在预脱硅阶段产生的硅钙材料副产品，以水化硅酸钙（C-S-H（I））（钙硅原子摩尔比”（Ca）／n（Si）-0．98～1．00）为主要矿相，属于具有高比表面积（733m^2／g）且孔隙发达的介孔材料，同时，其具有良好的酸碱缓冲性能（pH-2～10）以及一定的阳离子交换性能（Ca^2＋／H^＋）。介孔硅钙材料在35～60℃对Co（Ⅱ）吸附容量最高可达209～296mg／g，整个过程符合Langmuir单分子层化学吸附，为吸热反应，吸附可在3h内快速达到平衡，吸附机理主要为离子交换（占84．5％）。而对实际核电站大修废水的吸附试验结果表明，对其中的放射性Co（Ⅱ）去除率大于98．6％，并且其他放射性过渡金属离子也得到去除。在当前放射性核素的水泥固化处置中，介孔硅钙材料不仅与水泥有较高的相容性从而实现放射性核素的高效稳定化，同时还可替代部分水泥从而实现固化产物的减量化，具有较好的环境和经济效益，因此，该介孔硅钙材料在放射性废水核素去除方面具有较大的资源化应用潜力。To meet the needs of treatment of waste water containing low-level radioactive transition metal ions, using Co （Ⅱ） as a representative, the sorption ability of Co （Ⅱ） on calcium-silicate material, which is produced at the pre-desilication stage during the alumina extraction from the high-alumina fly ash by pre-desilication-soda-lime sintering technique,was studied. The results indicate that the calcium-silicate material, with hydration calcium silicate （C--S--H（Ⅱ ）） as the main mineral, is one of those mesoporous materials with high specific surface area（733 m^2/g） and developed void space structure. The material also has good acid and alkali buffer performance （pH = 2-10） and cation exchange capacity （Ca^2＋ / H＋ ）. The adsorption capacity can reach 209-296 mg/g in the temperature range of 35-60 ℃ for Co（ Ⅱ ）. The adsorption process is endothermic and consistent with Langmuir monolayer chemical adsorption. The adsorption equilibrium can be reached quickly within 3 h. Our results show that the main adsorption mechanism is most ion exchange（84.5%）. Moreover, the adsorption results for nuclear power plant overhaul wastewater show that more than 98.6% of the radioactive cobalt as well as other radioactive transition metal ions are removed. Speaking from the perspective of practical application, the mesoporous calciumsilicate material not only has high compatibility with cement which is good to the radionuclide stabilization, but also can replace part of cement to achieve the reduction of the radioactive solidification blocks. Because of the above mentioned environmental and economic benefits, the mesoporous calcium-silicate material evidently has potential application in radioac- tive transition nuclide removal of wastewater.

关 键 词：Co(Ⅱ) 介孔硅钙材料 吸附 离子交换 

分 类 号：X771[环境科学与工程—环境工程]