Fe^(2+) bio-oxidation influenced by toxic metal ions released from the dissolution of arsenic-bearing gold ores was investigated.Fe^(2+) bio-oxidation by moderately thermophilic microorganisms was studied under differ...Fe^(2+) bio-oxidation influenced by toxic metal ions released from the dissolution of arsenic-bearing gold ores was investigated.Fe^(2+) bio-oxidation by moderately thermophilic microorganisms was studied under different initial concentrations of Fe^(2+) and As(Ⅲ),and Monod equation was used to fit the Fe^(2+) bio-oxidation under different conditions.Results showed that the Fe^(2+) bio-oxidation rate increased as the initial Fe^(2+) concentration increased until it reached 12 g/L.As(Ⅲ)severely inhibited Fe^(2+) bio-oxidation.When the As(Ⅲ)concentration was 8 g/L,9 g/L Fe^(2+) was more than 200 h.The Monod equation fitted the Fe^(2+) bio-oxidation well.In the absence of As(Ⅲ),the maximum specific growth rate of the culture and the substrate affinity constant were 0.142 h^(−1) and 0.053 g/L,respectively.As(Ⅲ)inhibited Fe^(2+) bio-oxidation via competitive inhibition,and the inhibition constant was 0.0035 g/L.展开更多
The family of Cr（Ⅲ） and Fe（Ⅲ）-doped rutile pigments of nominal composition （M^ⅢM^V）xTi1-2xO2, with M^Ⅲ = Cr（Ⅲ） or Fe（Ⅲ） and M＇（V） = Sb, Nb, Ta, with x = 0.03, 0.15 and 0.25 were investigated as cera...The family of Cr（Ⅲ） and Fe（Ⅲ）-doped rutile pigments of nominal composition （M^ⅢM^V）xTi1-2xO2, with M^Ⅲ = Cr（Ⅲ） or Fe（Ⅲ） and M＇（V） = Sb, Nb, Ta, with x = 0.03, 0.15 and 0.25 were investigated as ceramic pigments covering the yellow-ochre-brown palette. The formulations containing Fe（Ⅲ） are novel compositions not included in the commercial rutile pigments. The materials were characterized by XRD （X-ray diffraction） analysis and FTIR （Fourier transformed infrared spectroscopy）. The transition temperature from anatase-to-rutile was estimated by the evolution of the spectral patterns. This crystal phase transition is responsible of the color formation. A higher distortion of TiO6 octahedra is observed in the case of （FeSb） containing cells which contribute to the enhancement of the light absorption. The coloring performance of all the formulations were evaluated by enameling the mixtures containing 5% pigments and commercial frits representative of single and double firing industrial processes. The chromatic values obtained are in the yellow to brown domain of the chromatic plot, depending on the composition of the pigment-frit batch. In the case of the Fe-glazes, and particularly the combination （FeNb）, the chromatic values are close to the best yellow tinting. This new FeNb-rutile pigment could be a more benign substitute of Cr-yellow pigments. The homogeneity of the enamels was confirmed by SEM （scanning electron microscopy）-EDAX （energy dispersive X-ray analysis） microscopy.展开更多
基金supported by the National Natural Science Foundation of China(No.51904339)the Collaborative Innovation Center for Clean and Efficient Utilization of Strategic Metal Mineral Resources,China.
文摘Fe^(2+) bio-oxidation influenced by toxic metal ions released from the dissolution of arsenic-bearing gold ores was investigated.Fe^(2+) bio-oxidation by moderately thermophilic microorganisms was studied under different initial concentrations of Fe^(2+) and As(Ⅲ),and Monod equation was used to fit the Fe^(2+) bio-oxidation under different conditions.Results showed that the Fe^(2+) bio-oxidation rate increased as the initial Fe^(2+) concentration increased until it reached 12 g/L.As(Ⅲ)severely inhibited Fe^(2+) bio-oxidation.When the As(Ⅲ)concentration was 8 g/L,9 g/L Fe^(2+) was more than 200 h.The Monod equation fitted the Fe^(2+) bio-oxidation well.In the absence of As(Ⅲ),the maximum specific growth rate of the culture and the substrate affinity constant were 0.142 h^(−1) and 0.053 g/L,respectively.As(Ⅲ)inhibited Fe^(2+) bio-oxidation via competitive inhibition,and the inhibition constant was 0.0035 g/L.
文摘The family of Cr（Ⅲ） and Fe（Ⅲ）-doped rutile pigments of nominal composition （M^ⅢM^V）xTi1-2xO2, with M^Ⅲ = Cr（Ⅲ） or Fe（Ⅲ） and M＇（V） = Sb, Nb, Ta, with x = 0.03, 0.15 and 0.25 were investigated as ceramic pigments covering the yellow-ochre-brown palette. The formulations containing Fe（Ⅲ） are novel compositions not included in the commercial rutile pigments. The materials were characterized by XRD （X-ray diffraction） analysis and FTIR （Fourier transformed infrared spectroscopy）. The transition temperature from anatase-to-rutile was estimated by the evolution of the spectral patterns. This crystal phase transition is responsible of the color formation. A higher distortion of TiO6 octahedra is observed in the case of （FeSb） containing cells which contribute to the enhancement of the light absorption. The coloring performance of all the formulations were evaluated by enameling the mixtures containing 5% pigments and commercial frits representative of single and double firing industrial processes. The chromatic values obtained are in the yellow to brown domain of the chromatic plot, depending on the composition of the pigment-frit batch. In the case of the Fe-glazes, and particularly the combination （FeNb）, the chromatic values are close to the best yellow tinting. This new FeNb-rutile pigment could be a more benign substitute of Cr-yellow pigments. The homogeneity of the enamels was confirmed by SEM （scanning electron microscopy）-EDAX （energy dispersive X-ray analysis） microscopy.
