硫化亚铁纳米颗粒(nFeS)已被证明可有效去除废水中的重金属(HM)。一种这样的方法,作为一项可持续技术,它引起了很多关注,是经由过程微生物原位合成nFeS。这里,硫酸盐还原细菌(SRB)菌株,硫化焦菌,最初用于生物合成硫化亚铁纳米颗粒(SRB-nFeS),然后从酸性矿山排水(AMD)中去除HM。利用X射线粉末衍射(XRD)对SRB-nFeS进行了表征,扫描电子显微镜(SEM)耦合到能量色散光谱仪(EDS),三维激发-发射矩阵(3D-EEM)光谱,傅里叶变换红外(FTIR)光谱和X射线光电子能谱(XPS)。这种表征表明,SRB介导SO42-还原为S2-形成nFeS,其中代谢物质充当与nFeS配位以形成具有改进稳定性的生物功能SRB-nFeS的络合剂。该合成途径的一个优点是nFeS与细菌表面的连接保护了SRB细胞免受HM毒性。此外,由于nFeS和SRB之间的协同作用,相对于组成组分,通过SRB-nFeS从溶液和AMD两者中去除HM得到增强。因此,在连续5次去除HM后,移除SRB-nFeS,Pb(Ⅱ)(92.6%),Cd(Ⅱ)(78.7%),Cu(Ⅱ)(76.0%),Ni(Ⅱ)(62.5%),Mn(Ⅱ)(62.2%),和Zn(Ⅱ)(88.5%)来自AMD。因此,该研究为SRB-nFeS的生物合成及其随后在从AMD中去除HMs的实际应用提供了新的见解。
Ferrous sulfide nanoparticles (nFeS) have proven to be effective in removing heavy metals (HMs) from wastewater. One such approach, which has garnered much attention as a sustainable technology, is via the in situ microbial synthesis of nFeS. Here, a sulfate-reducing bacteria (SRB) strain, Geobacter sulfurreducens, was used to initially biosynthesize ferrous sulfide nanoparticles (SRB-nFeS) and thereafter remove HMs from acid mine drainage (AMD). SRB-nFeS was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) coupled to an energy dispersive spectrometer (EDS), three-dimensional excitation-emission matrix (3D-EEM) spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Such characterization showed that SRB mediated the reduction of SO42- to S2- to form nFeS, where the metabolized substances functioned as complexing agents which coordinated with nFeS to form biofunctional SRB-nFeS with improved stability. One advantage of this synthetic route was that the attachment of nFeS to the bacterial surface protected SRB cells from HM toxicity. Furthermore, due to a synergistic effect between nFeS and SRB, HM removal from both solution and AMD by SRB-nFeS was enhanced relative to the constituent components. Thus, after 5 consecutive cycles of HM removal, SRB-nFeS removed, Pb(Ⅱ) (92.6%), Cd(Ⅱ) (78.7%), Cu(Ⅱ) (76.0%), Ni(Ⅱ) (62.5%), Mn(Ⅱ) (62.2%), and Zn(Ⅱ) (88.5%) from AMD This study thus provides new insights into the biosynthesis of SRB-nFeS and its subsequent practical application in the removal of HMs from AMD.