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排序方式: 共有802条查询结果,搜索用时 52 毫秒
1.
In the present research, nanostructured Pd–Cd alloy electrocatalysts with different compositions were produced using the electrodeposition process. The morphology of the samples was studied by scanning electron microscopy analysis. Also, the elemental composition of the samples was determined by energy-dispersive X-ray spectroscopy and elemental mapping tests. Tafel polarization and electrochemical impedance spectroscopy methods were employed to determine the electrochemical corrosion properties of the synthesized samples in a solution containing 0.5 M sulfuric acid and 0.1 M formic acid. The linear sweep voltammetry, cyclic voltammetry, and chronoamperometry techniques were also employed to evaluate the electrocatalytic activity of prepared samples toward the oxidation of formic acid. In this respect, the influence of some factors such as formic acid and sulfuric acid concentrations and also potential scan rate was investigated. Compared to the pure Pd sample, the Pd–Cd samples were more reactive for the oxidation of formic acid. Besides, the sample with a lower amount of Pd (Pd1·3Cd) demonstrated much higher electrocatalytic activity than the Pd7·1Cd and Pd2·1Cd samples. The observed high mass activity of 15.06 A mg?1Pd for the Pd1·3Cd sample which is 21.1 times higher than Pd/C is an interesting result of this study. 相似文献
2.
《中国有色金属学会会刊》2022,32(10):3404-3419
Mixed bacteria were enriched from heavy metals mine soil for cadmium (Cd(II))-containing wastewater treatment. Batch adsorption experiment results showed that the optimal pH, temperature, initial Cd(II) concentration, and biomass dosage were 6.0, 30 °C, 20 mg/L, and 1 g/L, respectively. Living biomass exhibited better Cd(II) removal efficiency (91.97%) than autoclaved biomass (79.54%) under optimal conditions. The isotherms and kinetics of living biomass conformed to the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. FTIR results implied that amine groups, hydroxyl groups and phosphoric acid play an important role in the Cd(II) adsorption process, while XRD results showed that crystalline Cd(OH)2 and CdO were obtained. After Cd(II)-containing wastewater treatment exposure, the dominant bacteria genera included Comamonas (39.94%), unclassified_f__Enterobacteriaceae (34.96%), Ochrobactrum (14.07%), Alcaligenes (4.84%), Bordetella (2.07%), Serratia (1.04%), and Bacillus (1.01%). Function prediction showed that the abundance of metabolic genes changed significantly. This study proposes the potential application of mixed bacteria for Cd(II)-containing wastewater treatment. 相似文献
3.
目的建立阳极溶出伏安法快速测定饮用水中镉、铅、铜、砷含量的检测方法。方法采用微波消解处理水样,以玻碳电极为工作电极,Ag/AgCl电极为参比电极,铂电极为对电极测定其溶出电流,采用外标法定量。结果在浓度为0.1~10μg/L范围内, Cd、Pb、Cu、As线性关系良好,方法检出限为0.00004~0.001 mg/L,加标回收率在98.10%~100.35%间。实际样品测定精密度小于2%。结论该方法稳定、快速、灵敏度高、准确度好,是一种高效的检测痕量重金属离子的方法。 相似文献
4.
采用沉淀-水热法和低温热磷化法分别制备了Cd0.5Zn0.5S纳米颗粒和Ni2P纳米片,利用超声空化效应合成了价格低廉、分散良好、高效的非贵金属磷化物助催化的Ni2P/Cd0.5Zn0.5S复合材料。通过XRD、SEM、UV-vis、PL以及电化学测试等手段进行了表征测试。以Na2S-Na2SO3为牺牲剂,在可见光(λ ≥ 420 nm)照射下对样品的光催化分解水产氢性能进行评价。结果表明,Ni2P显著提高了Cd0.5Zn0.5S的光催化产氢活性。当Ni2P含量为10 wt%时,复合材料的光催化产氢速率达到19133 μmol?g-1?h-1,为Cd0.5Zn0.5S产氢速率(7865 μmol?g-1?h-1)的2.4倍,且七次光催化循环实验后的产氢速率仍为初始值的91%。这可以归因于复合材料在具有更好的光吸收性能和较低的禁带宽度的同时,Ni2P为Cd0.5Zn0.5S提供的活性中心和界面效应有效地促进了光生载流子的有效分离和快速迁移。 相似文献
5.
6.
对某铅锌矿石采用优先浮选—磁选的工艺流程,分别获得了合格银精矿、含镉和银的锌精矿及合格的铁精矿,银、锌、镉、铁的回收率依次为89.75%、92.31%、89.10%、66.43%。 相似文献
7.
Heavy metals in maternal and cord blood 总被引:8,自引:0,他引:8
Raghunath R Tripathi RM Sastry VN Krishnamoorthy TM 《The Science of the total environment》2000,250(1-3):135-141
Heavy metal concentrations have been determined in maternal and cord blood samples collected from mothers in the age group 20-25 years with full-term neonates (37-40 weeks). The concentrations of Pb, Cd, Cu and Zn were found to be low in cord blood as compared to mother's blood and the ratio between cord blood and maternal blood for the respective elements was found to be approximately 0.80, 0.86, 0.47 and 0.40. On the other hand, the concentrations of Fe and Mg in the mother's blood were found to be lower than those in the cord blood. Prenatal exposure to lead in Mumbai, though low (5.1 microg/dl), is approximately 2-3 times higher than that observed in Canada or Italy. A strong correlation (r = 0.79) between the maternal and cord blood lead levels has been observed during the present study. 相似文献
8.
Y. C. Sharma G. Prasad D. I. Rupainwar 《The International journal of environmental studies》2013,70(4):315-320
The adsorption of Cd(II) onto wollastonite has been reported. Adsorption increased from 55.7 to 93.6% by decreasing the concentration of Cd(II) from 2.0 x 10‐4M to 0.5 x 10‐4M. The rearranged Lagergren equation has been used for dynamic modelling of the process. However, the value of rate constant at 30°C was found to be 3.17 x 10‐2min‐1. Equilibrium modelling was carried out using the Freundlich isotherm equation and constants have been calculated. Thermodynamic studies were carried out and values of standard free energy (?G°), enthalpy (?H°) and entropy (AS°) were calculated at various temperatures. Low temperatures favour the uptake of Cd(II) in the process. 相似文献
9.
Li Zhao Kaifeng Li Kai Lv Jinfeng Zhang Zhongliang Liu Haifeng Wang Qinzhuang Liu 《Journal of the American Ceramic Society》2022,105(2):1220-1231
Epitaxial Cd2SnO4 films were fabricated on MgO(00l) single crystalline substrates by pulsed laser deposition technique at various substrate temperatures and growth oxygen pressures. The microstructure, transport, and optical properties of the films were studied in detail. High-resolution X-ray diffraction and high-resolution transmission electron microscopy results demonstrate that all the Cd2SnO4 films are grown epitaxially on MgO(00l) substrates. Atomic force microscope images indicate that the films have smooth surface morphologies. Hall-effect measurements reveal that the epitaxial film grown at 680°C and 40 Pa presents the minimum resistivity value of 0.61 mΩcm and maximal Hall mobility of 32.87 cm2 V−1 s−1. The metal–semiconductor transitions of Cd2SnO4 films were observed and explained by competitive effects of two conductive mechanisms. The optical transmittance of the Cd2SnO4 films is higher than 75% in the visible and near-infrared range, and the optical bandgap was determined to be about 3.09 eV for the film grown at optimal condition. The band structure and density of states of the Cd2SnO4 were calculated by the density functional theory. 相似文献
10.
时效对Mg-Zn-Nd-Zr-Cd合金力学特性的影响 总被引:1,自引:0,他引:1
采用光学显微镜、XRD衍射分析仪、SEM扫描电镜、维氏硬度计、透射电子显微镜、万能拉伸试验机等仪器研究时效工艺对合金Mg-3.8Zn-2.8Nd-0.6Zr-0.6Cd力学特性的影响。结果显示,时效后合金强度有较大的提高,伸长率略有下降。采取双级时效90℃×10 h+150℃×8 h热处理,合金的屈服强度与抗拉强度分别达到320 MPa和350 MPa。双级时效热处理时,因为分解产物的数量更多、尺寸更小,因此强化效果要比单级时效的更明显。 相似文献