title: Coarsening of extracellularly biosynthesized cadmium crystal particles induced by thioacetamide in solution.
abstract: A novel coarsening route for extracellularly biosynthesized cadmium nanocrystals was investigated for the first time. In this process, the white rot fungus Coriolus versicolor was employed to take up cadmium ions and synthesize extracellular cadmium crystal particles. The coarsening of the particles was induced by thioacetamide under certain conditions. Scanning electron microscopy showed that the formed cadmium crystal particles were coarsened from about 100nm to 2-3μm. The corresponding energy-dispersive X-ray spectra confirmed the presence of proteins in the particles. The maximum removal efficiency of Cd(II) increased from 17% to 87%, and the corresponding sorption capacity of biomass increased from 4 to 24mgg(-1) with the completion of the coarsening process. The properties of the coarsened particles were also examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD analysis of fungal mycelial pellets embedded with the coarsened particles confirmed the formation of cubic crystalline cadmium sulfide particles. The TEM results suggest that the coarsened particles were composed of clusters of several smaller particles. The changes in the functional groups on the biomass surface were studied through Fourier transform infrared spectroscopy. Based on the results above, a possible mechanism for the formation and coarsening of cadmium crystal particle is also discussed.
authors.affiliation: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China. gqchen@hnu.cn
authors.forename: Gui-Qiu
authors.initials: GQ
authors.lastname: Chen
authors.forename: Zheng-Jun
authors.initials: ZJ
authors.lastname: Zou
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Zeng
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Fan
authors.forename: An-Wei
authors.initials: AW
authors.lastname: Chen
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Wen-Juan
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
mesh_terms: D002104:Cadmium / Q000737:chemistry / Q000378:metabolism*; D003460:Crystallization; D005110:Extracellular Space / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D013853:Thioacetamide / Q000737:chemistry / Q000378:metabolism*; D055454:Trametes / Q000378:metabolism* / Q000648:ultrastructure; D014961:X-Ray Diffraction
chemical_list: D002104:Cadmium; D013853:Thioacetamide