炼焦废水生化处理技术研究进展

综述了近几年来炼焦废水及炼焦废水中主要成分(酚类、氨类物质、氰化物)的生化处理方法.其中废水中酚类物质的去除方法有投加有效菌、超滤法等;去除氨类物质的方法有A2/O法、纳滤法和反渗透法等;去除氰化物的方法有生物法和化学法等.综合处理炼焦废水的方法有双层生物膜法、生物脱氮法和含铁活性污泥处理技术等.     

Ferrioxalate-mediated photodegradation and mineralization of 4-Chlorophenol

INTENTION, GOAL, SCOPE, BACKGROUND: Advanced oxidation processes are powerful methods which are capable of transforming refractory, nonbiodegradable and/or toxic organic compounds into harmless end products such as carbon dioxide and water. However, one commen problem of all advanced oxidation processes is the high demand of electrical energy for ultraviolet lamps, which causes high operational costs. Minimization of the required irradiation time, and therefore the energy consumption, by optimization of other reaction conditions such as catalyst-oxidant type and concentration, pH, temperature, pollutant/oxidant ratio etc., therefore continues to gain importance. OBJECTIVE: The main objective of this study was the minimization of the required irradiation time through optimization of the use of a newly patented catalyst, ferrioxalate, and also to compare the performance of this catalyst with the performance of other AOPs. METHODS: Oxidation of 4-chlorophenol by photo-Fenton process using potassium ferrioxalate as a mediator was studied in a lab scale photoreactor. The influence of parameters such as hydrogen peroxide and ferrioxalate concentrations, initial pH, power-output, oxalate/iron ratio and different iron sources was evaluated. An upflow photoreactor equipped with a 1000 Watt high-pressure mercury vapour lamp and operating in a recirculation mode was used during photodegradation experiments. The extent of the reduction of 4-chlorophenol, Total Organic Carbon and Chemical Oxygen Demand was used to evaluate the photodegradation reaction. RESULTS AND DISCUSSION: The optimum pH range observed was found to be 2.7-3. The efficiency of 4-chlorophenol oxidation increased with increasing concentrations of hydrogen peroxide and ferrioxalate, reaching a plateau after the addition of 10 and 0.072 mM of those reagents, respectively. Using an Oxalate/iron ratio of 12 was 18% less efficient than using a ratio of 3:1. The efficiency increased with increasing radiation power. However, this increase was not linear. The UV/ferrioxalate/H2O2 process, by which complete mineralization of 100 mg l(-1) 4-chlorophenol was achieved in 20 min of total reaction time, was the most efficient process among the alternatives applied. CONCLUSIONS: The use of ferrioxalate as the catalyst was found to be more efficient than the use of Fe(II) and Fe(III) iron species. It was possible to completely mineralize 4-chlorophenol. RECOMMENDATION AND OUTLOOK: The results of this study demonstrate that the ferrioxalate-mediated degradation of 4-chlorophenol requires less irradiation times than other advanced oxidation processes. There are mainly 19 phenol isomers and other toxic and nonbiodegradable organic compounds. We recommend that similar studies should be performed on many such compounds in order to attain a clear understanding of the performance of this catalyst. Because of its light sensitivity, this catalyst should be used immediately after its preparation. The use of low pressure mercury vapour lamps in this process should also be considered, since low power outputs may be enough for the process.     

Characterizing the source/sink behavior of double-layer building materials

A model is developed to predict the rate of mass transfer between a double-layer material and indoor air. The model allows non-uniform initial material-phase concentrations in each of the two layers and a transient influent gas-phase concentration to be considered. This model builds on a recently validated single-layer model and should prove useful in predicting the behavior of double-layer material assemblies. Many indoor furnishings and building structures are comprised of layers of different material. The approach taken here represents a first step in the development of a more generally applicable multi-layer model. An analytical solution to the double-layer model is obtained and a parametric analysis is performed illustrating the behavior of the model as a function of the primary model parameters. The paper concludes by examining the potential use of thin diffusion barriers to reduce material emission rates and a hypothetical example of emissions from an adhesive that is part of an adhesive/material assembly.     

Exposure of population and microenvironmental distributions of volatile organic compound concentrations in the EXPOLIS study

Determination of volatile organic compounds (VOCs) formed one part of the EU-EXPOLIS project in which the exposure of European urban populations to particles and gaseous pollutants was studied. The EXPOLIS study concentrated on 30 target VOCs selected on the basis of environmental and health significance and usability of the compounds as markers of pollution sources. In the project, 201 subjects in Helsinki, 50 in Athens, 50 in Basel, 50 in Milan and, 50 in Oxford and 50 in Prague were selected for the final exposure sample. The microenvironmental and personal exposure concentrations of VOCs were the lowest in Helsinki and Basel, while the highest concentrations were measured in Athens and Milan; Oxford and Prague were in between. In all cities, home indoor air was the most significant exposure agent. Workplace indoor air concentrations measured in this study were generally lower than the home indoor concentrations and home outdoor air played a minor role as an exposure agent. When estimating the measured personal exposure concentrations using the measured concentrations and time fractions spent at home indoors, at home outdoors, and at the workplace, it could be concluded that these three microenvironments do not fully explain the personal exposure. Other important sources for personal exposure must be encountered, the most important being traffic/transportation and other indoor environments not measured in this study.     

空气中挥发性有机物监测技术的研究进展

讨论了空气中挥发性有机化合物（VOCs）的监测分析方法研究进展。重点介绍了空气中VOCs的采集、分析和测定；简要叙述了样品前处理的新方法--固相微萃取法（SPME）与其它前处理方法的研究概况。     

Solubilization of substituted indole compounds by beta-cyclodextrin in water

The solubilization of four pairs of substituted indole compounds (SICs) by β-cyclodextrin (β-CD) in water was investigated. The results show that 1,2,3,4-tetrahydrocarbazole and N-methyl-1,2,3,4-tetrahydrocarbazole form 1:1 inclusion complexes with β-CD, while the other six SICs form 1:2 inclusion complexes, respectively. To each pair of SICs with similar structures, the differences between their solubilization in β-CD/water solutions has been explained by the difference of their contact area within the β-CD cavity, the difference of their molecule polarity, or the presence of hydrogen bond between SIC molecule and β-CD molecule.     

化工制药工艺残渣燃烧过程固氯研究

采用管式固定床反应器对化工制药工艺残渣的燃烧分解进行了实验研究,进一步通过加入氧化钙/碳酸钙来防止燃烧过程残渣中氯的释放.实验结果表明,残渣在燃烧时氯主要以氯化氢形式排出,加入固氯剂后能有效地抑制氯化氢的生成,且固氯效果随着钙化物投加量的增加而明显提高.当氧化钙/残渣比(质量比)达到0.8时,固氯率可达97%以上;当碳酸钙/残渣比(质量比)提高到2.0时,固氯率为76%.与此对应的Ca/Cl摩尔比分别为30和40.继续增加钙投加量,固氯效果基本不变.同时发现添加一定量的木屑在助燃的同时有助于提高固氯效果.     

CTMAB-膨润土吸附水中有机物的性能及应用

本文用溴化十六烷基三甲铵(CTMAB)-改性膨润土,研究了CTMAB-膨润土吸附水中α-萘胺、β-萘胺、α-萘酚、硝基苯和苯胺的性能和适宜条件.结果表明,CTMAB-膨润土对水中有机物的吸附能力与CTMAB在膨润土上的实际交换量有关,也与作用方式和有机物辛醇-水分配系数有关.CTMAB-膨润土对五种有机物的去除率顺序为:α-萘胺、β-萘胺、α-萘酚>硝基苯>苯胺.     

Labial gland marking secretion in males of two Scandinavian cuckoo bumblebee species (genusPsithyrus)

Summary Chemical components of the cephalic labial gland secretion, which most likely is used as a precopulatory attracting signal, were identified in males of the cuckoo bumblebeesPsithyrus vestalis (Geoffroy) andP. bohemicus (Seidl.) by gas chromatography-mass spectrometry (GC-MS). The former species has geranylcitronellyl acetate as main component, plus in decreasing amounts geranylcitronellol, an eicosadienal, an eicosenol, and an eicosenal. Another 17 fatty acid derivatives are present in minor amounts. The labial secretion ofP. vestalis differs distinctly in its chemistry from that of all of the 8 other ScandinavianPsithyrus species. In the taxonomically closely related (same subgenus)P. bohemicus, the labial gland secretion contains 16 fatty acid derivatives, of which 12 (75%) are present also in the secretion ofP. vestalis. Thus, both the labial gland secretions, and morphological traits lend support to the hypothesis that the two species share a common ancestor. The reproductive isolation between them is, at least in part, supported by the inclusion of a second biosynthetical pathway (the mevalonic acid pathway producing terpenoids) inP. vestalis, in addition to the pathway common to both species (the polyketide pathway producing fatty acid derivatives).     

Chloroacetic acids in environmental processes

The fate of chloroacetic acids (CAA) in forest soils was studied using radio-indicator methods. We showed that chloroacetic acids are both microbially degraded and simultaneously formed by chloroperoxidase-mediated chlorination of acetic and humic acids. The degree of biodegradation of chloroacetic acids in soil depends on their concentration. Dichloroacetic acid (DCA) is degraded faster than trichloroacetic acid (TCA). Chlorination of acetic acid led to a fast formation of dichloroacetic acid, whereas chlorination of humic acids gave rise to trichloroacetic acid. Both processes lead to a steady state in soil, participate in the chlorine cycle and possibly also in decomposition of organic matter in forest ecosystems.