水中钒的催化示波极谱测定法——钒—过硫酸铵—苯羟乙酸—硫酸新体系

本文基于在硫酸介质及100℃水浴加热条件下,痕量钒(V)对过硫酸铵氧化苯羟乙酸生成电活性物质苯甲醛这一慢反应的选择催化作用,建立了一个可测范围为0.04ng/ml-8.0ng/ ml,灵敏快速、选择性较佳的测定水中钒的催化示波极谱法。     

低钒和无钒基氧化物类NH_3-SCR催化剂研究进展

NH_3-SCR技术是脱硝领域中应用最多和最为成熟的技术。现已工业化应用的V_2O_5-WO_3(MoO_3)-TiO_2催化剂存在低温活性差、操作温度范围窄,活性组分V_2O_5具有生物毒性等缺陷。因此,开发高效、稳定且无毒的新型无钒基NH_3-SCR催化剂成为脱硝领域的研究热点。以不同活性基的氧化物催化剂为主线,综述了国内外低钒和无钒基氧化物类NH_3-SCR催化剂的研究进展,总结了原料配方和制备工艺对催化剂性能和反应机理的影响,并展望了脱硝领域未来可能的发展方向。     

钒对水稻生长的影响--溶液培养研究

通过水培试验 ,研究钒对水稻的毒害及钒与磷相互作用的影响 .试验结果表明 ,低浓度钒对水稻生长没有显著影响 ,但是随着钒浓度的不断增加 ,对水稻的干物质重量和根系生长均不利 .如钒浓度为 1 2 8mg·l- 1 时 ,水稻茎叶和根系的干重分别比不施钒的对照减少 49 9%和 5 5 1 % ,钒浓度愈高植株干重愈少 ,根系生长不良 ,表现出明显的钒中毒症状 .水稻茎叶及根系中磷的含量与钒的含量均呈极显著的负相关关系 .随着溶液中钒浓度的增加 ,水稻茎叶及根系吸收的钒量逐渐增加 ,而吸收的磷量却呈下降趋势 ,说明水稻钒毒害可抑制其对磷的吸收     

Vanadium metabolism investigation using substance flow and scenario analysis

Vanadium is a vital strategic resource, and vanadium metabolism is an important part of the national socio-economic system of China. This study conducts accounting and scenario analysis on the life cycle of vanadium metabolism in China. Based on the character- istics of vanadium life cycle and substance flow analysis （SFA） framework, we present a quantitative evaluation of a static anthropogenic vanadium life cycle for the year 2010. Results show that anthropogenic vanadium consumption, stocks, and new domestic scrap are at 98.2, 21.2, and 4.1 kt, respectively; new scrap is usually discarded. The overall utilization ratio of vanadium is 32.2%. A large amount of vanadium is stockpiled into tailings, debris, slags, and other spent solids. A scenario analysis was conducted to analyze the future developmental trend of vanadium metabolism in China based on the SFA frame- work and the qualitative analysis of technology advance- ment and socio-economic development. The baseline year was set as 2010. Several indicators were proposed to simulate different scenarios from 2010 to 2030. The scenario analysis indicates that the next 20 years is a critical period for the vanadium industry in China. This paper discusses relevant policies that contribute to the improvement of sustainable vanadium utilization in China.     

分光光度法测定水中钒全量的改进

为了寻求一种快速、安全、检测精度高的水体重金属钒检测方法,采用分光光度法分别测定样品以3种不同的显色体系在不同波长条件下的吸光度值,比较3种方法的优缺点及适用性。研究结果表明,以体积比为1∶1的磷酸溶液作为显色剂,在波长为380 nm条件下,实验结果线性最好、偏差最小。该方法操作简单,精度高,对水体中钒全量的检测范围为50~500 mg/L,适用于水体中在一定范围内钒全量的测定。     

SCR钒基催化剂吸附氨和水的密度泛函研究

利用密度泛函理论和原子簇模型,对NH3和H2O分子在选择性催化还原(SCR)脱硝催化剂表面不同吸附位上的吸附进行了研究.结果表明:NH3能吸附在V2O5表面的Lewis和Bronsted酸位,但在后者吸附位上更稳定.当V2O5以多聚物结构存在时,NH3能与O(1)H生成稳定的NH4 ,该物质在SCR反应中起着关键作用,吸附能为-128 kJ·mol-1;同时水也可与该吸附位形成稳定构型,吸附能为-97 kJ·mol-1.在V2O5表面,水与NH3的吸附能相当,两者发生竞争吸附,从而在一定程度上对SCR脱硝反应产生抑制作用.     

Vanadium and molybdenum concentrations in particulate from Palermo (Italy): analytical methods using voltammetry

The main purpose of this work was to develop a reliable method for the determination of vanadium (V) and molybdenum (Mo) in atmosphere particles or aerosols because they can not be readily measured using conventional techniques. For this research, 30 particulate samples were collected from five different stations located at Palermo, Italy. We used the catalytic adsorptive stripping voltammetry and differential pulsed voltammetry to measure V and Mo in atmospheric particulate, respectively. The represented method includes advantages of high sensitivity, high selectivity, simplicity, reproducibility, speed and low costs. The quantification limits for V and Mo are, respectively, 0.57 and 0.80 ng·m⁻³. The precision, expressed as relative standard deviation (RSD %), was about 2% for both metals. The mean recoveries of added V and Mo were about 99.5% and ranged from 97% to 101%. Vanadium concentrations in particulate samples collected in Palermo area ranged from 0.57 to 7.7 ng·m⁻³, while Mo concentrations were in the range 0.8–51 ng·m⁻³. In many cases the concentrations of two elements in the particulate samples fall below the detection limits. The mean concentrations for V and Mo in particulate samples, collected in Palermo area, were respectively 3.1 and 5.9 ng·m⁻³.     

Inhalation of vanadium modifies gap junctions in mouse seminiferous tubules

Vanadium (V) adhering to inhaled particles has been associated with male reproductive alterations. Intercellular junction proteins, such as connexin 43, constitute the blood-testes barrier. These proteins are crucial for the reconstitution of the barrier during spermatogenesis. Normally, connexins are located between cell membranes but in cells exposed to certain metals or which are transformed, their location is altered. The objective of this study was to examine the effect of the inhalation of vanadium pentoxide on the distribution of connexin 43 in seminiferous tubules of mice. Immunohistochemical localization of connexin 43 demonstrated the redistribution of the protein that increased with time of exposure while intensity of stain on the membranes decreased. In previous studies, reduction in the actin and γ-tubulin stain intensity upon V inhalation has been observed. All these alterations may explain the reprotoxic effect associated with vanadium.     

改进催化光度法测定水中的微量钒

采用改进催化光度法测定微量钒,即利用微量钒催化溴酸钾氧化甲基紫溶液褪色实现快速测定水中的微量钒。在50mL容量瓶中,在pH为1.6的硫酸加入量0.90mL、0.0100mol/L的溴酸钾溶液加入量4.50mL、2.5×10-4mol/L的甲基紫溶液加入量5.00mL的条件下,聚乙二醇-200作活化剂时,在92℃恒温反应12min,加钒和不加钒溶液的吸光度之差与钒质量浓度呈线性关系。该法的测定波长为580nm,检出限为5.2×10-8g/L,最大相对标准偏差为4.3%,回收率为95.8%~104.0%。该法可用于湖水、化工厂排水中微量钒的直接测定。