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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p H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286.46 mg·L~(-1)、生物量为3.2 g·L~(-1)、温度50℃以及p H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.
The precious metal platinum was recovered by the strain of Enterococcus faecalis Z5 (accession number CCTCC M2012445) which was separated by itself. The possibility of recovering the platinum in the solution as nano-particles under the condition of external electron donor was discussed. The effects of initial concentration of platinum, biomass, temperature and p H on recovery process were discussed, and the probable mechanism of recovery of platinum nanoparticles by Enterococcus faecalis Z5 was discussed. The results showed that the Enterococcus faecalis Z5 strain could recover platinum nanoparticles, Including biosorption and bioreduction.The optimum recovering conditions were platinum initial concentration of 286.46 mg · L -1, biomass of 3.2 g · L -1, temperature of 50 ℃ and p H value of 6 The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed that the recovered product was platinum nanoparticle with a size of about 5 nm and was mainly distributed in the periplasm.X-ray photoelectron spectroscopy (XPS) ) Was first reduced to Pt (II), then reduced to Pt (0) and Pt (II) to Pt (0) was the limiting step. FTIR analysis showed that the hydroxyl groups Amido functional groups may play a role in the recovery process.