摘要
选取碳酸盐矿化菌进行培养,利用其在代谢过程中分泌的尿素酶分解尿素产生CO32-,从而将游离态的放射性Sr2+转化为稳定态Sr CO3.通过能谱分析(EDS)、扫描电子显微镜(SEM)、X射线衍射(XRD)和傅里叶变换红外光谱(FT-IR)对沉淀产物进行分析,并计算核素固结率.结果表明:微生物诱导沉积的沉淀为大小混杂、表面多孔的Sr CO3晶体颗粒,并相互黏结形成不规则的团聚体;c(Sr2+)、ρ(尿素)及培养时间等对Sr CO3晶体形貌产生影响;菌体本身作为成核位点参与了碳酸盐矿化菌诱导Sr2+的矿化过程.当c(Sr2+)为0.05 mol/L、ρ(尿素)为30 g/L、p H为8.0并在30℃下培养72 h时,生成较大的微生物矿化物团聚体,对Sr2+固结率可达98.32%,可实现放射性核素稳定化处置.
The solidifying of Sr^2＋ by carbonate mineralization bacteria, Bacillus pasteurii, in an aqueous solution was investigated. CO3^ 2- was produced by the enzyme digestion process of the species when urea was decomposing. Biochemical properties of urease from bacteria were involved in transforming free radioactive Sr^2＋ into stable SrCO3. Various analysis and testing techniques, such as EDS, SEM, XRD and FT-IR, were used to analyse the precipitate. The experimental results showed that the microbiologically-induced SrCO3 crystal particles have porous surface in chaotic sizes, bonding together forming irregular groups. Concentrations, cultivation time and urea concentrations of Sr^2＋influenced the forming of SrCO3 crystal morphology. It was also found that the bacteria participate in the progress of carbonate mineralization bacteria induced Sr^2＋ mineralization as nucleation sites. The solidifying rate reached a peak of 98.32% when the Sr^2＋concentration was set as 0.05 tool/L, urea concentration was 30 g/L and pH was 8, cultivation was at 30 R2 for 72 h, and therefore radionuclide stabilization treatment could be achieved.
出处
《环境科学研究》
EI
CAS
CSSCI
CSCD
北大核心
2015年第1期157-162,共6页
Research of Environmental Sciences
基金
国家自然科学基金项目(11075134)
国家国防科技工业局项目(科工二司[2011]1081号)
核废物与环境安全国防重点学科实验室开放基金项目(12zxnp08)
关键词
碳酸盐矿化菌
核素Sr^2+
矿化
carbonate-mineralization bacteria
nuclideSr^2＋
mineralization
