Wang Maolin, Wu Shijun, Guo Jianan, Liao Zisheng, Yang Yongqiang, Chen Fanrong, Zhu Runliang
CAS Key Laboratory of Mineralogy and Metallogeny & Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, 510640 Guangzhou, China; CAS Center for Excellence in Deep Earth Science, 511 Kehua Street, 510640 Guangzhou, China; University of Chinese Academy of Sciences, 19 Yuquan Road, 100049 Beijing, China.
CAS Key Laboratory of Mineralogy and Metallogeny & Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, 510640 Guangzhou, China; CAS Center for Excellence in Deep Earth Science, 511 Kehua Street, 510640 Guangzhou, China.
J Hazard Mater. 2022 Jul 15;434:128936. doi: 10.1016/j.jhazmat.2022.128936. Epub 2022 Apr 16.
Carbonate-bound uranium (U) is critical in controlling the migration of U in circumneutral to alkaline conditions. The potential release risk of carbonate-bound U should be concerned due to the contribution of mineral replacement. Herein, we explored the fate of U during the conversion process from microbial-induced calcite to hydroxylapatite (HAP) and investigated the phase and morphology evolution of minerals and the immobilization efficiency, distribution, and stability of U. The results showed that most calcite could convert to HAP during the conversion process. The aqueous residual U was below 1.0 mg/L after U-HAP formation, and the U removal efficiencies were enhanced by 20.0-74.4% compared to the calcite precipitation process. XRD and TEM results showed that the products were a mixture of HAP and uramphite. The elemental mapping results showed that most U concentrated on uramphite while a handful of U distributed homogeneously in calcite and HAP matrixes. The stability test verified that U-bearing HAP decreased the U solubility by 98-100% relative to calcite due to the uramphite formation and U incorporation into HAP. Our findings demonstrated that the combinations of microbial-induced calcite precipitation and calcite-HAP conversion could facilitate the U immobilization in treating radioactive wastewater and soil.
碳酸盐结合态铀（U）对于控制铀在中性至碱性条件下的迁移至关重要。由于矿物置换的作用，碳酸盐结合态铀的潜在释放风险值得关注。在此，我们探究了微生物诱导方解石向羟基磷灰石（HAP）转化过程中铀的归宿，并研究了矿物的相和形态演变以及铀的固定效率、分布和稳定性。结果表明，在转化过程中，大多数方解石可转化为HAP。铀-羟基磷灰石形成后，水相残余铀低于1.0 mg/L，与方解石沉淀过程相比，铀去除效率提高了20.0 - 74.4%。XRD和TEM结果表明，产物是HAP和磷铀矿的混合物。元素映射结果表明，大多数铀集中在磷铀矿上，而少量铀均匀分布在方解石和HAP基质中。稳定性测试证实，由于磷铀矿的形成以及铀掺入HAP，含铀HAP相对于方解石使铀的溶解度降低了98 - 100%。我们的研究结果表明，微生物诱导方解石沉淀和方解石-HAP转化相结合可促进放射性废水和土壤中铀的固定。
