Recovery of Elemental Tellurium Nanoparticles by the Reduction of Tellurium Oxyanions in a Methanogenic Microbial Consortium

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• 作者：Adriana Ramos-Ruiz ; Jim A. Field ; Jean V. Wilkening ; Reyes Sierra-Alvarez
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：February 2, 2016
• 年：2016
• 卷：50
• 期：3
• 页码：1492-1500
• 全文大小：395K
• ISSN：1520-5851

文摘

This research focuses on the microbial recovery of elemental tellurium (Tep>0p>) from aqueous streams containing soluble tellurium oxyanions, tellurate (Tep>VIp>), and tellurite (Tep>IVp>). An anaerobic mixed microbial culture occurring in methanogenic granular sludge was able to biocatalyze the reduction of both Te oxyanions to produce Tep>0p> nanoparticles (NPs) in sulfur-free medium. Tep>IVp> reduction was seven times faster than that of Tep>VIp>, such that Tep>IVp> did not accumulate to a great extent during Tep>VIp> reduction. Endogenous substrates in the granular sludge provided the electron equivalents required to reduce Te oxyanions; however, the reduction rates were modestly increased with an exogenous electron donor such as H₂. The effect of four redox mediators (anthraquinone-2,6-disulfonate, hydroxocobalamin, riboflavin, and lawsone) was also tested. Riboflavin increased the rate of Tep>IVp> reduction eleven-fold and also enhanced the fraction Te recovered as extracellular Tep>0p> NPs from 21% to 64%. Lawsone increased the rate of Tep>VIp> reduction five-fold, and the fraction of Te recovered as extracellular material increased from 49% to 83%. The redox mediators and electron donors also impacted the morphologies and localization of Tep>0p> NPs, suggesting that NP production can be tailored for a particular application.