Some characteristics of Ag＋ biosorption and bioreduction by Lactobacillus sp. A09 biomass were reported. The optimum pH value of Ag＋ biosorption by strain A09 was 4.5. Temperature(6～ 50 ℃ ) did not affect the bios...Some characteristics of Ag＋ biosorption and bioreduction by Lactobacillus sp. A09 biomass were reported. The optimum pH value of Ag＋ biosorption by strain A09 was 4.5. Temperature(6～ 50 ℃ ) did not affect the biosorption. The biosorptive efficiency (91％ ) and biosorptive capacity(Ag＋ 125 mg· g－ 1 dry weight biomass ) were achieved under the conditions of Ag＋ 100 mg· L－ 1, biomass 800 mg· L－ 1, pH 4.5 and 30 ℃ for 24 h contact. TEM analysis indicated that A09 biomass could reduce Ag＋ to Ag0 as Ag particles on the surface of cells. IR spectroscopy showed that － CO2－ and － HN－ C=O on the surface of cells may involve in the precession for adsorbing Ag＋ .展开更多
Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag（NH3）2]^＋ to Ago in the solution into which some amount...Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag（NH3）2]^＋ to Ago in the solution into which some amount of OH^- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solution. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.展开更多
The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt ...The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt 4+ adsorptive efficiency of the strain D01 was as high as 94.3% under the conditions of 100 mg Pt 4+ /L, 1 g biomass/L, pH 3.5 and at 30 ℃ for 24 h. Moreover, it was confirmed from anode stripping voltammetry that the strain D01 possessed a strong reducibility. The TEM analysis indicated that the strain D01 was able to adsorb and reduce Pt 4+ to Pt 0, small particles. The XPS result further supported the reduction of Pt 4+ to Pt 2+ , followed by the further recuction to Pt 0. The IR spectrum implied that D01 biomass adsorption of Pt 4+ may result in the complexation of the CO bond to the Pt species.展开更多
Objective:To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera(M.oleifera).Methods:10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of...Objective:To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera(M.oleifera).Methods:10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of AgNO_3 and was heated at 60-80 ℃ for 20 min.A change from brown to reddish color was observed.Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy(TEM) was performed.Results:TEM showed the formation of silver nanoparticles with an average size of 57 nm.Conclusions:M.oleifera demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions(Ag^+ to Ag^0). Biological methods are good competents for the chemical procedures,which are eco-friendly and convenient.展开更多
文摘Some characteristics of Ag＋ biosorption and bioreduction by Lactobacillus sp. A09 biomass were reported. The optimum pH value of Ag＋ biosorption by strain A09 was 4.5. Temperature(6～ 50 ℃ ) did not affect the biosorption. The biosorptive efficiency (91％ ) and biosorptive capacity(Ag＋ 125 mg· g－ 1 dry weight biomass ) were achieved under the conditions of Ag＋ 100 mg· L－ 1, biomass 800 mg· L－ 1, pH 4.5 and 30 ℃ for 24 h contact. TEM analysis indicated that A09 biomass could reduce Ag＋ to Ag0 as Ag particles on the surface of cells. IR spectroscopy showed that － CO2－ and － HN－ C=O on the surface of cells may involve in the precession for adsorbing Ag＋ .
基金Supported by the National Natural Science Foundation of China (No.20376076).
文摘Bioreduction as a novel nanoparticle synthesizing technology attracts increasing attention. Dried cells of the bacterium Aeromonas sp. SH10 rapidly reduced [Ag（NH3）2]^＋ to Ago in the solution into which some amount of OH^- was introduced. The surface plasmon resonance centered at 425 nm on the UV-vis spectra and five broad Bragg reflections on the XRD pattern showed that stable silver nanoparticles were formed during the bioreduction process. TEM and SEM observations suggested that the silver nanoparticles were uniform in size and well dispersed on the cells and in the solution. Therefore, silver nanoparticles could be prepared rapidly by this bioreduction technology.
基金Supported by the National Natural Science Foundation of China(No.2 97430 0 1 and No.2 9876 0 2 6 )
文摘The properties of Pt 4+ adsorption and its reduction by Bacillus megaterium D01 were studied by means of ICP, anode stripping voltammetry, TEM, IR and XPS. The results of ICP analyses showed that the Pt 4+ adsorptive efficiency of the strain D01 was as high as 94.3% under the conditions of 100 mg Pt 4+ /L, 1 g biomass/L, pH 3.5 and at 30 ℃ for 24 h. Moreover, it was confirmed from anode stripping voltammetry that the strain D01 possessed a strong reducibility. The TEM analysis indicated that the strain D01 was able to adsorb and reduce Pt 4+ to Pt 0, small particles. The XPS result further supported the reduction of Pt 4+ to Pt 2+ , followed by the further recuction to Pt 0. The IR spectrum implied that D01 biomass adsorption of Pt 4+ may result in the complexation of the CO bond to the Pt species.
文摘Objective:To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera(M.oleifera).Methods:10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of AgNO_3 and was heated at 60-80 ℃ for 20 min.A change from brown to reddish color was observed.Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy(TEM) was performed.Results:TEM showed the formation of silver nanoparticles with an average size of 57 nm.Conclusions:M.oleifera demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions(Ag^+ to Ag^0). Biological methods are good competents for the chemical procedures,which are eco-friendly and convenient.
