| 生物法回收贵金属铂纳米颗粒及其机制 |
| 摘要点击 1724 全文点击 982 投稿时间：2015-12-18 修订日期：2016-02-25 |
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| 中文关键词 铂 二次回收 粪肠球菌 纳米颗粒 生物还原 还原机制 |
| 英文关键词 platinum secondary recovery Enterococcus faecalis nanoparticles bio-reduction reduction mechanism |
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| 中文摘要 |
| 利用自行分离的粪肠球菌Z5(Enterococcus faecalis Z5)菌株(保藏号CCTCC M2012445)回收贵金属铂,探讨了其在外源电子供体条件下以纳米颗粒形式回收溶液中化合态铂的可能性,研究了铂初始浓度、生物量、温度以及pH值对回收过程的影响,探讨了粪肠球菌Z5回收铂纳米颗粒过程的可能机制.结果表明,粪肠球菌Z5菌株可以回收铂纳米颗粒,回收过程主要包括生物吸附和生物还原.铂初始浓度为286.46mg·L-1、生物量为3.2g·L-1、温度50℃以及pH值为6时为其最佳回收条件.X射线衍射(XRD)和透射电镜(TEM)分析表明,回收产物为5 nm左右粒径的铂纳米颗粒,主要分布于细胞周质.X射线电子能谱(XPS)分析显示,Pt(Ⅳ)首先被还原为Pt(Ⅱ),然后被还原为Pt(0),且从Pt(Ⅱ)还原成Pt(0)为限制步骤,傅里叶红外(FTIR)分析显示菌体表面的羟基和酰胺基官能团可能在回收过程中起作用. |
| 英文摘要 |
| This paper illustrated an approach of using a self-isolated bacterium Enterococcus faecalis Z5(CCTCC M2012445) to recover platinum nanoparticles from aqueous solution, and exploring its possibility under the condition of providing an exogenous electron donor. At the same time, the impacts of initial Pt concentration, biomass, temperature and pH on recovery process were researched to explore the possible mechanism of recovery process. The results showed that Enterococcus faecalis Z5 could recover platinum nanoparticles and there were two steps:bio-sorption and bio-reduction. And the initial Pt concentration 286.46 mg·L-1, biomass 3.2 g·L-1, temperature 50℃ and pH 6 for biorecovering were optimized. The TEM and XRD results indicated that the reduction products were platinum nanoparticles, of which most were distributed on the periplasm and the diameters were about 5 nm. Moreover, as shown by XPS figures, Pt (Ⅳ) was firstly reduced to Pt (Ⅱ), then further reduced to Pt (0) and nanoparticles were formed. The reduction of Pt (Ⅱ) to Pt (0) was a rate-limiting step. And the FTIR result showed the corresponding peaks of hydroxyl and amide group changes on the bacterium before and after reduction, probably playing an important role in the reduction process. |
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