| 模拟废水中钯的微生物回收及其对亚甲基蓝的催化特性 |
| 摘要点击 1343 全文点击 509 投稿时间：2016-02-21 修订日期：2017-03-20 |
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| 中文关键词 钯 二次回收 粪肠球菌 纳米颗粒 四氧化三铁 |
| 英文关键词 palladium secondary recovery Enterococcus faecalis nanoparticles ferriferous oxide |
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| 中文摘要 |
| 以粪肠球菌（Enterococcus faecalis）Z5 菌株（CCTCC M2012445）为菌种资源，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钯的可能性，研究了工业废液（IW）、废旧电路板（PCBS）和废汽车催化剂（SAC）3种模拟废水中钯的回收率，分析了废水中其它离子对钯回收率的影响. 结果表明，粪肠球菌Z5 菌株可以从3种模拟废水中回收钯纳米颗粒. X射线衍射和透射电镜分析表明，回收产物为10 nm 左右粒径的钯纳米颗粒，主要分布于细胞周质. 3种废水中钯的回收率依次为IW> SAC> PCBS，其中吸附率依次为99.8%（6 h）、99.7%（8 h）、90.3%（12 h），还原率依次为99.9%（4 h）、99.9%（6 h）、80.4%（36 h）. 模拟废水中Pt（Ⅳ）、Ag（Ⅰ）、Cu（Ⅱ）、Au（Ⅲ） 和Fe（Ⅱ）对钯的还原和吸附过程都存在影响. 具体地，钯的还原效率受影响程度依次为Au（Ⅲ）> Pt（Ⅳ）> Cu（Ⅱ）> Ag（Ⅰ）> Fe（Ⅱ）. 进一步将回收所得的纳米钯掺杂四氧化三铁，可应用于非均相芬顿反应中染料亚甲基蓝降解，80 min内亚甲基蓝的降解率为96.7%，显示出良好的催化性能. |
| 英文摘要 |
| By using Enterococcus faecalis Z5 strain (CCTCC M2012445) as a microbial resource, this study explored the possibility of recovering palladium (Pd) in the form of nanoparticles by adding an electron donor; investigated the Pd biorecovery efficiency of three kinds of simulated wastewaters including industrial waste processing leachates (IW) , printed circuit board scrap (PCBS) , and spent automotive catalyst (SAC); and analyzed the effect of other metal ions contained in simulated wastewater on Pd biorecovery efficiency. The results showed that the E. faecalis Z5 could recover Pd(Ⅱ) as palladium nanoparticles from the three simulated wastewaters. X-ray diffraction and transmission electron microscopy analysis indicated that the recovered product was Pd nanoparticles that were about 10 nm in size and mainly distributed in the periplasm of the cells. The order of Pd(Ⅱ) biorecovery efficiency from the three kinds of wastewaters was IW> SAC> PCBS. The biosorption efficiencies for IW, SAC, and PCBS were 99.8% (6 h), 99.7% (8 h), and 90.3% (12 h), respectively, and the bioreduction efficiencies were 99.9% (4 h), 99.9% (6 h), and 80.4% (36 h). Other metal ions contained in the simulated wastewaters such as Pt(Ⅳ), Au(Ⅲ), Ag(Ⅰ), Cu(Ⅱ), and Fe(Ⅱ) affected both the biosorption and bioreduction processes. The degree of matrix effects on the Pd(Ⅱ) bioreduction efficiency were in the order Au(Ⅲ)> Pt(Ⅳ)> Cu(Ⅱ)> Ag(Ⅰ)> Fe(Ⅱ). Further doping the recovered Pd nanoparticles with ferriferous oxide enabled the products to catalyze the degradation of methylene blue in heterogeneous Fenton reactions, which showed 96.7% degradation rate of methyl blue within 80 min. |
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