Copper-catalyzed chlorination and condensation of acetylene and dichloroacetylene

The chlorination and condensation of acetylene at low temperatures is demonstrated using copper chlorides as chlorinated agents coated to model borosilicate surfaces. Experiments with and without both a chlorine source and borosilicate surfaces indicate the absence of gas-phase and gas-surface reactions. Chlorination and condensation occur only in the presence of the copper catalyst. C₂ through C₈ organic products were observed in the effluent; PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed that is consistent with the observed product distributions. Similar experiments with dichloroacetylene indicate greater reactivity in the absence of the copper catalyst. Reaction is observed in the gas-phase and in the presence of borosilicate surfaces at low temperatures. The formation of hexachlorobenzene is only observed in the presence of a copper catalyst. PCDD/F were only observed from extraction of the borosilicate surfaces. A global reaction model is proposed for the formation of hexachlorobenzene from dichloroacetylene.     

骆马湖富营养化和生态状况调查与评价

为了了解骆马湖水质状况，在2005年对骆马湖富营养化状态和生态特性进行了调查，并结合“十五”期间的监测资料进行了分析。2005年骆马湖水体中总氮和总磷的平均值超《地表水环境质量标准》（GB3838-2002）中Ⅲ类，超标情况分别为0．78倍和0．54倍，达到湖库特定项目Ⅳ类水标准，骆马湖处于轻度富营养化状态。对骆马湖生态特征分析表明，由于该湖泊的形态以及“藻型浊水状态”和“泥沙型浊水状态”交替出现，遏制了湖水从高营养盐含量向全面富营养化状态演变，保障了底栖动物的良好生长环境，从而形成了骆马湖独特的环境生态平衡。     

Status and trends of mercury pollution of the atmosphere and terrestrial ecosystems in Poland

The goal of this paper is to assess the current status and trends of total mercury (THg) contamination of the atmosphere and terrestrial ecosystems in Poland. The study shows that the reduced domestic and worldwide atmospheric emission of Hg resulted in decreased THg level in the terrestrial biotope and biosphere. Considering that Poland is one of the main Hg emitters in Europe, the THg concentrations in its abiotic environment are still elevated. However, the THg level in terrestrial organisms is relatively low, which is because a large proportion of Hg deposited on land is accumulated in organic-rich soils. Regarding the THg concentration, consumption of wildlife and livestock from Poland is safe for humans. Nevertheless, the authors indicate the need for effective environmental monitoring, based on selected bioindicators, which is crucial considering the slowing reduction of Hg emission combined with the consequences of the changing climate.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01505-1.     

Experimental and statistical validation of SPME-GC-MS analysis of phenol and chlorophenols in raw and treated water

A procedure based on solid-phase microextraction (SPME) and gas chromatography coupled with mass spectrometry (GC-MS) was developed and validated in order to analyse 10 phenols in water samples. The optimised conditions were obtained using polyacrylate fibre (PA), 20ml of sample volume, 10% NaCl, pH 4.0 and direct extraction at 35 degrees C and 1000rpm, for 40min. The linear range and quantification limits for these compounds by SPME-GC-MS were defined. An evaluation of the main uncertainty sources of this method is included, which allows expanded uncertainties in the 9.4-35% range for the majority of the compounds. The main source of uncertainty is associated with matrix effects. The validated method is suitable for monitoring the production and distribution of potable water and was used, in field trials, for the analysis of samples from main intakes of water (surface or underground) and from water supply system of a large area (Lisbon and neighbour municipalities).     

Energy and exergy optimization of food waste pretreatment and incineration

With the aim of upgrading current food waste (FW) management strategy, a novel FW hydrothermal pretreatment and air-drying incineration system is proposed and optimized from an energy and exergy perspective. Parameters considered include the extracted steam quality, the final moisture content of dehydrated FW, and the reactor thermal efficiency. Results show that optimal working condition can be obtained when the temperature and pressure of extracted steam are 159 °C and 0.17 MPa, the final moisture content of dehydrated FW is 10%, and the reactor thermal efficiency is 90%. Under such circumstance, the optimal steam energy and exergy increments reach 194.92 and 324.50 kJ/kg-FW, respectively. The novel system is then applied under the local conditions of Hangzhou, China. Results show that approximately 2.7 or 11.6% (from energy or exergy analysis perspective) of electricity can be additionally generated from 1 ton of MSW if the proposed novel FW system is implemented. Besides, comparisons between energy and exergy analysis are also discussed.

     

高分子重金属絮凝剂MCC制备及除铜去浊性能

以壳聚糖、L-半胱氨酸为原料,通过酰胺化反应制备了一种具有重金属捕集功能的高分子重金属絮凝剂-2-氨基-3-巯基丙酰壳聚糖(MCC)。以含铜废水为处理对象,通过正交实验研究了MCC的最佳制备条件,对其除铜性能进行了全面探讨,并对絮体形貌进行了观察和分析。结果表明,在最佳条件下制得的MCC具有除浊和捕集重金属离子双重功能,形成的絮体量较大、沉速快,出水水质好,重金属回收率较高,残渣稳定,不易造成二次污染,絮体分形维数越小,空隙越多,除铜效果越好。     

Mathematical description, optimization and prediction of synergistic interaction of fluoride and xylitol

The potential ability of various physical or chemical agents to enhance their effect when they are applied simultaneously with each other is well-known. The purpose of this study was to adjust a simple mathematical model to describe, optimize and predict a synergistic interaction between fluoride and xylitol on acid production by mutans streptococci. The model suggests that the synergism is caused by the additional effective damage arising from an interaction of sublesions induced by each agent. These sublesions are considered to be ineffective when each agent is used individually. The predictions of the model were verified by comparison with experimental data published by other researchers. It was shown that the model describes the experimental data, predicts the greatest value of the synergistic effect and the condition under which it can be achieved. The synergistic effect appeared to decline with any deviation from the optimal value of the ratio of effective damages produced by each agent alone.     

Study of inclusion complex of beta-cyclodextrin and nitrobenzene

beta-cyclodextrin can react with nitrobenzene to form an inclusion complex which is characterized by (1)H NMR and powder X-ray diffractometry. The ratio of beta-CD to NB in inclusion complex is determined as 1:1. At 25 degrees C, the dissociated constant, K(D), of the inclusion complex is measured as 6.5 x 10(-3) M in neutral solution (pH=7.0), but in alkali (pH=13.5), K(D) is 3.2 x 10(-2) M which is much larger than that measured in neutral.     

Adsorption of molybdate and tetrathiomolybdate onto pyrite and goethite: effect of pH and competitive anions

The adsorption of two major molybdenum (Mo) species, molybdate (MoO4(2-)) and tetrathiomolybdate (MoS4(2-)) onto two main iron minerals pyrite (FeS2) and goethite (FeOOH) is addressed to elucidate the possible mechanisms of molybdenum immobilization in anoxic sediments. Suspensions of MoS4(2-) (or MoO4(2-)) and goethite (or pyrite) in 0.1M NaCl solution were equilibrated under anoxic conditions at 25 degrees C in the pH range from 3 to 10. The competitive effects of sulfate, phosphate, and silicate on the adsorption of MoO4(2-) and MoS4(2-) by pyrite and goethite are also addressed. Adsorption of MoO4(2-) and MoS4(2-) on pyrite and goethite is in general well described by a Langmuir model at low pH; the extent of sorption is a function of pH and the surface loading. Maximum sorption is observed in the acidic pH range (pH<5) at low surface loading. The adsorption of molybdenum (micromol g(-1)) depends upon Mo species and on the type of iron mineral following the order: MoS4(2-)-goethite > MoO4(2-)-goethite > MoS4(2-)-pyrite > MoO4(2-)-pyrite. Phosphate appears to compete strongly with MoO4(2-) and MoS4(2-) for the sorption sites of pyrite and goethite. The strength of the phosphate competitive effect follows the sequence of MoO4(2-)-goethite approximately = MoO4(2-)-pyrite > MoS4(2-)-pyrite > MoS4(2-)-goethite. Silicate and sulfate have a negligible effect on the sorption of MoO4(2-) and MoS4(2-). The preferred adsorption by iron mineral of MoS4(2-), as well as its behavior in the presence of competitive anions suggests that tetrathiomolybdate species may be an ultimate reservoir and may control Mo enrichment in the sediments.     

二相厌氧-混凝法处理制浆造纸综合废水的工艺设计及调试

湖南某造纸厂采用二相厌氧 混凝法处理制浆造纸综合废水取得了显著效果 ,CODCr排放总量削减率达 80 % ,水体水质明显改善。本文介绍了该工程的工艺设计及调试。     

The mechanism and kinetics of ultrasound-enhanced electrochemical oxidation of phenol on boron-doped diamond and Pt electrodes

The research on ultrasound (US) enhanced electrochemical oxidation of Phenol (Ph) on boron-doped diamond (BDD) and Pt electrodes is studied. The enhancement by US on BDD is much greater than for Pt. With the assistance of US, the degradation rate and current efficiency on BDD are increased by 301% and 100%, respectively, while those on Pt are 51% and 49%. The difference of the enhancement on these two electrodes is caused by the fact that mass transport, adsorption amount and electrode reaction affected by US on BDD are different from those of Pt. The kinetics investigation on intermediates formed during electrochemical degradation show that the variety of intermediates produced on BDD is less than for Pt. In the presence of US, on both electrodes, no change occurred to the amounts of the intermediate species. However, time for intermediates to reach the highest concentration is cut down. This effect for degradation of Ph on BDD is more obvious than for Pt. The present research indicates that BDD is suitable for degradation of Ph by US assisted electrochemical oxidation.     

Effect of cadmium on growth, ultramorphology of leaf and secondary metabolites of Phyllanthus amarus Schum. and Thonn

The pollution is increasing in the environment by different kinds of human activities, which results in the accumulation of heavy metals including cadmium in the soil and water and it causes different types of problems to living beings. As the plants are utilized by human being as food and medicine, therefore, it is mandatory to see the effect of metals on plants. In this context, efforts have been made to observe the effect of different concentration of Cadmium (Cd) on Phyllanthus amarus Schum. and Thonn., because Cd is the widespread metal and the plants response to low and high level of exposure is a complex phenomenon. P. amarus is mostly grown as weed in agricultural and waste lands. It is a reputed plant used in Indian indigenous systems of medicine with hepatoprotective, diuretic, stomachic properties and is recently being used for the treatment of hepatitis B. The study revealed that Cd causes significant decrease in fresh and dry weight, length of root and shoot, protein, chlorophyll, carotenoids and sugar and increase in starch content. It is interesting to note that the therapeutically active compounds—phyllanthin and hypophyllanthin, enhanced at certain levels of Cd due to abiotic stress. Besides, the ultramorpholical changes were also observed in stomatal opening and wax deposition on both the surfaces of leaves.     

论污染防控与生态保育

近年来,不仅是生态保育,污染防控也越来越呈现出区域性乃至整体性,这是由环境自身运动规律决定的。污染防控和生态保育必须重宏观、重预防、重效率。环境污染加剧生态破坏,使脆弱的生态环境雪上加霜,也使生态问题更加复杂化,但环境污染不是生态环境问题的全部。生态问题必须用生态的办法来解决。违反自然规律的行为必须禁止,让不堪重负的生态系统休养生息。生态保育不仅是解决生态问题的基本出路,也是从深层次上解决污染问题的基本出路。生态保育是生态文明建设的一个重要组成部分。不论是污染防控,还是生态保育,都必须同时遵循自然规律和社会主义市场经济规律,激发市场主体保护环境的内生动因,方能可持续发展。     

Assessment of bioconcentration and secondary poisoning of surfactants

The relevance of the bioconcentration behaviour of surfactants for the secondary poisoning assessment and for the risk characterisation in the bird and mammalian food chain has been investigated. The approach used is described in the recently revised EU Technical Guidance Document for the Risk Assessment of Substances. The results demonstrate that, based on experimentally derived bioconcentration factors, environmental concentrations and effects in animals, there is a clear level of safety for both linear alkylbenzene sulphonate (LAS) and alcohol ethoxylates (AE), the most important surfactants by volume. To assess other surfactants used in detergents, a bioconcentration factor that would need to be attained for secondary poisoning to be of concern has been estimated from predicted environmental concentrations and known long-term effects data in animals. Based on the known structural similarity of these surfactants to LAS and AE and the ubiquitous nature of the enzymatic systems that are present in biotransformation processes in organisms, it is concluded that bioconcentration of these surfactants to these levels is highly unlikely. Therefore the potential for secondary poisoning effects of these surfactants is extremely low.     

Depuration of copper and zinc by green oysters and blue mussels of Taiwan

This paper describes depuration processes of copper and zinc in green oysters (Crassostrea gigas) and in blue mussels (Mytilus smarangdium) collected from an environment with heavy copper contamination, and then transferred to natural clean seawater. Results show that the total loss of copper content per oyster is an exponential function of exposure time for the first 6 days with a depuration rate of 351 microg g(-1) day(-1) and then levels off. During this exponential decrease period approximately 67% of the copper accumulated in green oysters was depurated. However, when the copper contents in the oysters decreased from 2225 +/- 111 microg g(-1) to 344 +/- 18.7 microg g(-1) the depuration rates decreased from 245 microg g(-1) day(-1) to 0.08 microg g(-1) day(-1). This means that green oysters had a 16-fold higher copper depuration rate (351 microg g(-1) day(-1)) than normal oysters (21.5 microg g(-1) day(-1)) for the first 6 days. However, the depuration of accumulated copper and zinc by the mussels was a fast process in natural clean seawater. About 91% of the accumulated copper was lost during the first 6-day period; copper contents declined from 20.2 +/- 3.41 microg g(-1) to 1.80 +/- 0.21 microg g(-1). Only 36% of the accumulated zinc was lost during a depuration period of 6 days. Calculations show that the biological half-lives of copper in green and normal oysters were 11.6 and 25.1 days, respectively. The biological half-lives of zinc in green and normal oysters were 16.7 and 30.1 days, respectively. In spite of the relatively low initial copper content in blue mussels being 20.2 +/- 3.41 microg g(-1), the biological half-life is only 6.40 days. From these results it is important to emphasise that the fastest turnover rate is for copper in blue mussels. However, zinc is more retentive in blue mussels than copper.     

Current issues and uncertainties in the measurement and modelling of air-vegetation exchange and within-plant processing of POPs

Air-vegetation exchange of POPs is an important process controlling the entry of POPs into terrestrial food chains, and may also have a significant effect on the global movement of these compounds. Many factors affect the air-vegetation transfer including: the physicochemical properties of the compounds of interest; environmental factors such as temperature, wind speed, humidity and light conditions; and plant characteristics such as functional type, leaf surface area, cuticular structure, and leaf longevity. The purpose of this review is to quantify the effects these differences might have on air/plant exchange of POPs, and to point out the major gaps in the knowledge of this subject that require further research. Uptake mechanisms are complicated, with the role of each factor in controlling partitioning, fate and behaviour process still not fully understood. Consequently, current models of air-vegetation exchange do not incorporate variability in these factors, with the exception of temperature. These models instead rely on using average values for a number of environmental factors (e.g. plant lipid content, surface area), ignoring the large variations in these values. The available models suggest that boundary layer conductance is of key importance in the uptake of POPs, although large uncertainties in the cuticular pathway prevents confirmation of this with any degree of certainty, and experimental data seems to show plant-side resistance to be important. Models are usually based on the assumption that POP uptake occurs through the lipophilic cuticle which covers aerial surfaces of plants. However, some authors have recently attached greater importance to the stomatal route of entry into the leaf for gas phase compounds. There is a need for greater mechanistic understanding of air-plant exchange and the 'scaling' of factors affecting it. The review also suggests a number of key variables that researchers should measure in their experiments to allow comparisons to be made between studies in order to improve our understanding of what causes any differences in measured data between sites.     

四氯化碳的生产与应用及其淘汰策略

四氯化碳是一种消耗臭氧层物质,其生产和消费都面临着严峻的淘汰形势.简要叙述了四氯化碳的生产技术,以四氯化碳为原料生产大宗化学品和精细化学品的转化技术,四氯化碳作为化工助剂在我国的应用情况以及相应的淘汰方法和技术进展.     

微絮凝-超滤-膜系统深度处理印染废水

针对二级处理后达标排放的印染废水,采用微絮凝-超滤-膜系统组合工艺深度处理,研究了超滤对污染物的去除效果以及对后续膜系统运行的影响。结果表明,超滤可以有效地去除废水中的浊度,去除率高达98.5%,对COD、色度和总溶解固体(TDS)也有一定的去除率,分别为17%、10%以下和5%;超滤的运用可以大大延长后续膜系统的化学清洗周期,间接提升膜系统产水总量,产水水质符合印染生产要求,成本仅为1.8元/t,整套工艺具有较好的应用前景。