核能因其清洁、高效、来源广泛,被认为是最有前景的替代传统化石燃料的能源之一.遗憾的是,铀矿石储存量有限,限制了核能的可持续发展,同时产生的含铀废水会造成环境污染问题.因此,从放射性含铀废水中提取和回收铀对于核能的可持续发展和环境保护是必要的.本文以高锰酸钾(KMnO4)和氯化钴(CoCl2·6H2O)为原料,采用水热法和共沉淀法制备了 2种锰钴尖晶石氧化物(CoMn2O4和MnCo2O4).通过X射线衍射仪(X-ray diffractometry,XRD)、扫描电子显微镜(Scanning electron microscopy,SEM)和 BET(Brunauer-Emmett-Teller)比表面积测试对 2 种材料的晶体结构、形貌及比表面积进行分析,探究了溶液pH对2种材料吸附铀酰离子的影响.结果表明,水热法制备的CoMn2O4吸附效果更好.因此,研究了吸附时间、吸附温度和轴溶液初始浓度对CoMn2O4吸附性能的影响.在298 K、pH=5的条件下,CoMn2O4对铀酰离子的吸附过程符合准二级动力学模型和Langmuir等温吸附模型,最大吸附量为229.06 mg·g-1.本文采用水热法制备的材料在从含铀废水中吸附铀方面表现出巨大潜力.
Preparation of manganese cobalt metal oxides and their performance for uranium adsorption
Nuclear energy has been regarded as one of the promising energy sources to replace traditional fossil fuels due to its clean,efficient and wide range of sources.Unfortunately,the limited storage of uranium ore restricted the sustainable development of nuclear energy,together with the generation of uranium-containing wastewater resulting in the problems of environmental pollution.Therefore,extracting and recycling uranium from radioactive uranium-containing wastewater is necessary for the sustainable development of nuclear energy and environmental protection.Two manganese-cobalt spinel oxides(CoMn2O4 and MnCo2O4)were prepared from potassium permanganate(KMnO4)and cobalt chloride(CoCl2·6H2O)by hydrothermal and coprecipitation methods,respectively.The crystal structure,morphology and specific surface area of the two materials were analyzed by X-ray diffractometry(XRD),scanning electron microscopy(SEM)and BET(Brunauer-Emmett-Teller)specific surface area test.The effect of solution pH on the adsorption of uranyl ions by the two materials was investigated.The results show that the CoMn2O4 prepared by the hydrothermal method has the better adsorption effect.Therefore,the effects of adsorption time,adsorption temperature and initial concentration of uranium solution on the adsorption performance of CoMn2O4 were investigated.The adsorption process of CoMn2O4 on uranyl ions at 298 K and pH=5 conforms to the quasi-secondary kinetic model and Langmuir isothermal adsorption model,and the maximum adsorption amount is 229.06 mg·g-1.The material prepared by the hydrothermal method in this paper shows great potential for uranium adsorption from uranium-containing waste water.