Fenton高级氧化工艺降解苯酚模拟废水的动力学实验研究

针对Fenton高级氧化反应动力学过程进行了精细研究和深入探讨,结果表明:Fenton氧化法降解苯酚模拟废水的过程并不是单纯地符合一级动力学过程,其降解过程符合公式的形式。实验还研究了过氧化氢、亚铁离子、pH值等反应参数与反应进程的关系,为其实际应用提供了数据积累和理论依据。     

Visualizing different uranium oxidation states during the surface alteration of uraninite and uranium tetrachloride

Low-temperature alteration reactions on uranium phases may lead to the mobilization of uranium and thereby poses a potential threat to humans living close to uranium-contaminated sites. In this study, the surface alteration of uraninite (UO₂) and uranium tetrachloride (UCl₄) in air atmosphere was studied by confocal laser scanning microscopy (CLSM) and laser-induced fluorescence spectroscopy using an excitation wavelength of 408 nm. It was found that within minutes the oxidation state on the surface of the uraninite and the uranium tetrachloride changed. During the surface alteration process U(IV) atoms on the uraninite and uranium tetrachloride surface became stepwise oxidized by a one-electron step at first to U(V) and then further to U(VI). These observed changes in the oxidation states of the uraninite surface were microscopically visualized and spectroscopically identified on the basis of their fluorescence emission signal. A fluorescence signal in the wavelength range of 415–475 nm was indicative for metastable uranium(V), and a fluorescence signal in the range of 480–560 nm was identified as uranium(VI). In addition, the oxidation process of tetravalent uranium in aqueous solution at pH 0.3 was visualized by CLSM and U(V) was fluorescence spectroscopically identified. The combination of microscopy and fluorescence spectroscopy provided a very convincing visualization of the brief presence of U(V) as a metastable reaction intermediate and of the simultaneous coexistence of the three states U(IV), U(V), and U(VI). These results have a significant importance for fundamental uranium redox chemistry and should contribute to a better understanding of the geochemical behavior of uranium in nature. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A process integration approach to industrial water conservation: a case study for an Indian starch industry

A case study for water using network of a Starch industry in the state of Gujarat, India, is undertaken with an aim to reduce demineralised water and freshwater flow rates and consequently the wastewater flow rate. The problem was identified as a multi contaminant, reuse and recycle problem. The freshwater consumption and demineralised water consumption were 100 t/h and 51 t/h respectively before modification and the network was dealing with three major contaminants such as total organic content, total dissolved solids and total suspended solids. A program was developed in MATLAB for analysis using Water Pinch. The improved water using network designed for the present work consumed less demineralised and freshwater. The reductions are of the tune of 28% and 64.38% for demineralised and fresh water respectively. Due to alteration in piping, there will be a saving of 406 026 INR per year, which will be utilized for development of efficient environment policy for the company. The entire concept had been implemented on plant level on 1st February-2009 and the reductions are of the tune of 25% and 60% for demineralised and fresh water respectively.     

ICP-OES法测定大气和废气颗粒物中的金属元素

将微波消解法与电感耦合等离子体发射光谱法(ICP-OES)相结合,对大气和废气颗粒物中金属元素的微波消解条件及ICP-OES测定条件进行了优化研究,建立了大气和废气颗粒物中铝(Al)、钡(Ba)、镉(Cd)、铬(Cr)、铜(Cu)、锰(Mn)、钼(Mo)、镍(Ni)、铅(Pb)、锡(Sn)、锶(Sr)及锌(Zn)等金属元素的测定方法。对方法的检出限进行了测定,各元素的检出限均低于0.04 mg/L;对方法的精密度进行了测定,各元素的相对标准偏差在2.59%～7.14%之间;对方法的准确度进行了测定,质控滤膜中各元素的回收率在89.6%~119%之间,颗粒物参考物质中各元素的回收率在85.1%～107%之间,并将该方法成功应用到 TSP、污染源废气实际样品中金属元素的测定。     

Review of corporate environmental indicators

This paper reviews a series of environmental indicators developed in the last years that were found suitable to be applied at corporate level for the evaluation of production processes and products. The indicators reviewed in this paper were classified into four main groups: 1) Indicators of Energy and Material Flows; 2) Indicators with a Territorial Dimension; 3) Indicators of Life-Cycle Assessment; 4) Indicators of Environmental Risk Assessment. Integrative and single index indicators such as the ecological footprint or carbon footprint were found as the most appealing for enterprises, although there is a need to advance in the field to combine the simplicity required at corporate level for tracking and reporting environmental data, and the scientific rigor and transparency necessary to make the scores reliable. Hence, for each of the indicators revised it was stated what they do and do not measure so that misleading information was not used for decision making at corporate level.     

基于AHP法白洋淀湿地生态评价

以白洋淀湿地为研究对象,采用层次分析法对湿地进行生态评价.结果表明:湿地最主要的功能是生态服务功能(0.64);其次是生态保护功能(0.26);最次是资源功能(0.1).单项指标中最重要的是缓洪滞沥功能(0.31),最次为土地资源功能(0.004).最后,通过计算湿地综合评价指数(CEI=0.58),根据自然保护区生态...     

微波强化光催化对直接耐酸大红4BS的降解

采用微波无极灯强化光催化对直接耐酸大红4BS的降解进行研究。初步考察反应温度、微波功率、pH值、催化剂TiO2浓度、曝气量、直接耐酸大红4BS初始浓度、外加氧化剂H2O2量等因素对直接耐酸大红4BS降解效果的影响。实验结果表明,反应最佳温度是55℃、最佳催化剂TiO2投加量为6 g/L;较低pH值、高微波功率、外加氧化剂H2O2有利于直接耐酸大红4BS的降解。与常规的光催化相比,微波减弱pH值和染料初始浓度对降解效率的影响。在优化工艺参数和未加H2O2条件下,反应4 h后,质量浓度为500 mg/L的直接耐酸大红4BS降解率达到90%。     

CO2 emissions in calcium carbide industry: An analysis of China's mitigation potential

China's calcium carbide output has dominated the global market for several years, driven by the demand for PVC (polyvinyl chloride), a fundamental polymer material and also the primary downstream product of calcium carbide in China. The fast growth of this energy-intensive industry leads to an inevitable increase in CO₂ emissions. However, there is a large reduction potential with process improvement in this industry which is currently characterized by widespread outdated facilities. In this study, we attempt to assess the reduction potential of CO₂ emissions in China's calcium carbide production, based on the analysis of CO₂ emission patterns and estimation of the emission amount. Three scenarios regarding process improvement are employed to conduct this assessment. The results imply that the cumulative CO₂ abatement in the Current Policy Scenario and in the Strengthened Policy Scenario from 2008 to 2020, compared with the Baseline Scenario, are 89.0 and 107.6 million t, respectively. The specific measures and policy implications to achieve this potential are also discussed in the article.     

民航空管质量安全监察人员胜任能力模型研究

以空管政事分离改革后民航空管质量安全监察人员胜任事业单位内部质量安全监察职责为目标,从教育、培训、技能和经验四个方面分析构成民航空管质量安全监察人员胜任能力的因素,并构建了胜任能力指标体系.运用网络分析法(ANP)构建了民航质量安全监察人员胜任能力的网络结构模型;利用三角模糊数(FUZZY)对网络结构模型中各个因素进行重要度比较,得到权重向量.鉴于评价指标之间存在的较强的关联性,利用非线性加权综合法,构建了民航空管质量安全监察人员胜任能力模型,该模型对评价指标中取值较小的指标反应灵敏,能够更好地体现不同监察人员之间胜任能力的差异.利用该模型对某空管单位来自于不同背景的5名监察人员进行评价,结果与上一年度该空管单位的绩效考核结果一致,证明了模型的合理性.     

Photocatalytic degradation of Rhodamine B bymicrowave-assisted hydrothermal synthesized N-doped titanate nanotubes

Microwave-induced nitrogen-doped titanate nanotubes（NTNTs） were characterized by transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, Fourier transform infrared spectroscopy（FT-IR）, Zeta potential analysis,specific surface area（SBET）, and UV-Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O＋, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV-Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B（RhB） via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10-3, 2.4 × 10-3and 8.0 × 10-4sec-1at pH 3, 7, and 11, respectively.