title: Photocatalytic properties of zinc sulfide nanocrystals biofabricated by metal-reducing bacterium Shewanella oneidensis MR-1.
abstract: Accumulation and utilization of heavy metals from wastewater by biological treatment system has aroused great interest. In the present study, a metal-reducing bacterium Shewanella oneidensis MR-1 was used to explore the biofabrication of ZnS nanocrystals from the artificial wastewater. The biogenic H2S produced via the reduction of thiosulfate precipitated the Zn(II) as sulfide extracellularly. Characterization by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and field emission scanning electron microscope (FESEM) confirmed the precipitates as ZnS nanocrystals. The biogenic ZnS nanocrystals appeared spherical in shape with an average diameter of 5 nm and mainly aggregated in the medium and cell surface of S. oneidensis MR-1. UV-vis DRS spectra showed ZnS nanoparticles appeared a strong absorption below 360 nm. Thus, the photocatalytic activity of ZnS was evaluated by the photodegradation of rhodamine B (RhB) under UV irradiation. The biogenic ZnS nanocrystals showed a high level of photodegradation efficiency to RhB coupled with a significant blue-shift of maximum adsorption peak. A detailed analysis indicated the photogenerated holes, rather than hydroxyl radicals, contributed to the photocatalytic decolorization of RhB. This approach of coupling biosynthesis of nanoparticles with heavy metal removal may offer a potential avenue for efficient bioremediation of heavy metal wastewater.
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Xiao
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Ma
authors.affiliation: Key Laboratory of Ion Beam Bioengineering, Institute of Technical Biology & Agriculture Engineering, Chinese Academy of Sciences, Hefei 230031, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Yuan
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Peng-Cheng
authors.initials: PC
authors.lastname: Liu
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Yu-Bin
authors.initials: YB
authors.lastname: Lei
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: ddl@ujs.edu.cn.
authors.forename: Dao-Lin
authors.initials: DL
authors.lastname: Du
authors.affiliation: School of The Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Jian-Fan
authors.initials: JF
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: yujief@hit.edu.cn.
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Feng
mesh_terms: D002384:Catalysis; D005456:Fluorescent Dyes / Q000737:chemistry; D019216:Metals, Heavy / Q000378:metabolism*; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010782:Photolysis; D012235:Rhodamines / Q000737:chemistry; D020592:Shewanella / Q000378:metabolism*; D013440:Sulfides / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000032:analysis; D014961:X-Ray Diffraction; D017967:Zinc Compounds / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D005456:Fluorescent Dyes; D019216:Metals, Heavy; D012235:Rhodamines; D013440:Sulfides; D014874:Water Pollutants, Chemical; D017967:Zinc Compounds; C029773:rhodamine B; C031238:zinc sulfide
keywords: Biofabrication; Photocatalysis; Shewanella oneidensis MR-1; ZnS nanocrystal