Zhuang Fan, Xiang Xiaowu, Hu Jin, Xiong Jing, Zhang Teng, Zhou Lei, Jiang Guoping, Zhang Min, Liu Zhenghua, Yin Huaqun, Xia Ling, Mahmoud Ibrahim Ahmed Ibrahim, Meng Delong
Key Laboratory of Biometallurgy, Ministry of Education, School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China.
Dongkou County Agricultural Bureau, Shaoyang 422300, China.
Toxics. 2024 Dec 26;13(1):17. doi: 10.3390/toxics13010017.
The development of the non-ferrous metal industry is generating increasingly large quantities of wastewater containing heavy metals (e.g., Sb). The precipitation of heavy metals by microorganisms involves complex mechanisms that require further investigation to optimize bioremediation technologies. In this study, we employed a sulfate-reducing bacteria (SRB) strain CSU_dl to treat the antimony (Sb)-containing wastewater; the behavior of Sb and mechanisms underlying precipitation were investigated by characterizing the precipitates. The results showed that the abiotic factors constraining SRB bacterial growth greatly affect Sb forms and precipitation. For instance, Sb precipitation maximumly occurred at pH 6 and 7, or C:N ratio of 10:1 and 40:3 for Sb(III) and Sb(V), respectively, resulting in a maximum Sb removal rate of 94%. Interestingly, we found that substantial antimonate and antimonite were adsorbed on the SRB cell surface, indicating that cell surface is a critical reaction site of Sb transformation and precipitation. Sb was adsorbed to the cell surface by C-C and C=O groups, and was further precipitated by forming SbS and SbS or was coprecipitated with the P-containing group. Partial Sb(V) reduction was also observed on the SRB cell surface. These results provided a deep insight into the Sb bio-transformation and were an advancement with respect to understanding bioremediation of Sb-contaminated wastewater.
有色金属工业的发展产生了越来越多含重金属（如锑）的废水。微生物对重金属的沉淀涉及复杂机制，需要进一步研究以优化生物修复技术。在本研究中，我们使用硫酸盐还原菌（SRB）菌株CSU_dl处理含锑（Sb）废水；通过对沉淀物进行表征，研究了Sb的行为及沉淀的潜在机制。结果表明，限制SRB细菌生长的非生物因素极大地影响了Sb的形态和沉淀。例如，Sb沉淀在pH值为6和7时达到最大值，对于Sb(III)和Sb(V)，C:N比分别为10:1和40:3时沉淀最大，导致最大Sb去除率为94%。有趣的是，我们发现大量的锑酸盐和亚锑酸盐吸附在SRB细胞表面，这表明细胞表面是Sb转化和沉淀的关键反应位点。Sb通过C-C和C=O基团吸附到细胞表面，并通过形成SbS和SbS进一步沉淀或与含磷基团共沉淀。在SRB细胞表面还观察到部分Sb(V)的还原。这些结果深入洞察了Sb的生物转化，在理解含Sb废水的生物修复方面取得了进展。
