Abstract:

Sporosarcina pasteurii induced carbonate-uranium co-precipitation for the remediation of low concentration uranium wastewater under the presence of calcium was studied. The results show that the bacteria can secrete urease to hydrolyze urea to induce calcite and promote its co-precipitation with uranium, so that the removal rate of uranium in wastewater reaches 95.38%. The analysis indicated that Sporosarcina pasteurii was able to tolerate uranium concentrations up to 500 mg/L, while low concentration of uranium had a slight promotion effect on bacterial growth. In addition, the decrease of uranium concentration is directly related to the concentration of Ca²⁺ (C_Ca). The increase of C_Ca improved the uranium removal rate. The temperature at about 30℃ and alkaline environment are favorable to the co-precipitation of uranium and calcite. The precipitate was characterized by XRD and SEM-EDS. XRD analysis showed that the precipitate was composed of calcite. SEM-EDS analysis further suggested that the precipitated component contains uranium element. Combined with the digestion results, uranium was fixed into the precipitated product in the way of co-precipitation during the formation of calcite. This study shows that Sporosarcina pasteurii induced carbonate-uranium co-precipitation has a potential application prospect in the remediation of low concentration uranium contaminated wastewater.

Key words: uranium pollution, bioremediation, Sporosarcina pasteurii, urease, carbonate-uranium co-precipitation

摘要：

对有钙源条件下Sporosarcina pasteurii诱导碳酸盐-铀共沉淀修复低浓度铀废水的性能开展了试验研究。试验结果表明，该细菌能分泌脲酶水解尿素诱导产生方解石并促使其与铀发生共沉淀，使废水中铀的去除率达到95.38%；该细菌能够耐受的铀浓度高达500 mg/L；铀的去除率随Ca²⁺浓度的升高而增加；温度在30℃左右和碱性环境有利于方解石与铀的共沉淀。对沉淀产物进行XRD、SEM-EDS表征分析表明，其主要成分为方解石，且包含铀元素；消解分析表明，在方解石形成过程中铀以共沉淀的方式被固定到了沉淀产物中。本研究表明，Sporosarcina pasteurii诱导碳酸盐-铀共沉淀对修复低浓度铀废水有潜在应用前景。

关键词: 铀污染, 生物修复, Sporosarcina pasteurii, 脲酶, 碳酸盐-铀共沉淀