Characteristics and ozone formation potential of volatile organic compounds in emissions from a typical Chinese coking plant

Coking industry is an important volatile organic compounds (VOCs) emission source in China, however, detailed information on VOCs emissions is lacking. Therefore, we selected a typical mechanized coking plant and collected air samples according to the Emission Standard of Pollutants for Coking Chemical Industry (GB16171-2012). Using gas chromatography-mass spectrometry method, we analyzed the VOCs in the air samples, and applied maximum increment reactivity (MIR) rule to estimate ozone formation potential (OFP) of the VOCs emitted from the coke production. More than 90 VOCs species were detected from the coking plant, including alkanes, alkenes, alkynes, aromatic hydrocarbons, halogenated hydrocarbons and oxygenated VOCs. The concentrations of VOCs (ρ(VOCs)) generated at different stages of the coking process are significantly different. ρ(VOCs) from coke oven chimney had the highest concentration (87.1 mg/m³), followed by coke pushing (4.0 mg/m³), coal charging (3.3 mg/m³) and coke oven tops (1.1 mg/m³). VOCs species emitted from the coke production processes were dominated by alkanes and alkenes, but the composition proportions were different at the different stages. Alkenes were the most abundant emission species in flue gases of the coke oven chimney accounting for up to 66% of the total VOCs, while the VOCs emissions from coke pushing and coal charging were dominated by alkanes (36% and 42%, respectively), and the alkanes and alkenes emitted from coke oven top were similar (31% and 29%, respectively). Based on above results, reduction of VOCs emissions from coke oven chimney flue gases is suggested to be an effective measure, especially for alkenes.     

Citric and Oxalic Acids Effect on Pb and Zn Uptake by Maize and Winter Wheat

Abstract

A pot experiment was conducted to investigate the influence of citric and oxalic acids effect on Pb and Zn uptake by corn and winter wheat. The experiment was employed with citric acid (CA) applied at 3 rates (0, 1.5 and 3.0 mmol kg^?1 soil), oxalic acid (OA) at 3 rates (0, 1.5 and 3.0mmol kg^?1 soil) and citric acid combined with oxalic acid (1.5 mmol citric acid combined with 1.5 mmol oxalic acid kg^?1). Two types of soil were chose in the experiment. One was collected from the agricultural soil near a battery-recycling factory in Anhui province, China (site A) and the other was collected from a Pb-Zn mine residues in Hunan province, China (site B). The results showed that soil pH varied with the different treatment of citric and oxalic acids. However, there were no differences in all the treatments. 3.0mmol CA kg^?1 soil addition significantly increased the concentrations of the CaCl₂-extractable Pb and Zn and other treatments have no significantly increased. The highest shoot concentrations of Pb and Zn in both species occurred in application of 3.0 mmol CA/kg^?1 soil and shoot concentrations of Pb and Zn in both species were significantly higher than the controls in this treatment. Shoot yields declined with application of citric and oxalic acids, indicating that the plants were sensitive to the toxicity of the metals or the amendments. The highest Pb uptake values by maize and wheat werell2.3 and 77.2 μg pot1 in soil of site A, and occurred with the control and 3.0 mmol CA/kg^?1 soil respectively.     

高性能聚乙烯纤维手套防护性能研究

采用实验室测试和现场调查相结合的方法,测试了高性能聚乙烯纤维手套的防护性能,调查手套的适应性、防护时间和费用支出,探讨了其应用前景。     

Spatial distribution of health risks for residents located close to solvent-consuming industrial VOC emission sources

Emissions derived from the consumption of organic solvents have been proven to be the primary industrial source of volatile organic compounds (VOCs). In conjunction with epidemiologic studies, water-based paints (WBPs) and solvent-based paints (SBPs) were selected as representatives of newly developed solvents and traditional solvents, respectively, to simulate the effects of consuming solvents emitted during industrial production. And non-carcinogenic and carcinogenic risks to residents near emission sources were studied in detail. The results showed that the spatial distribution of health risks varied with meteorological conditions and type of emission source, and the prevailing wind direction strongly affected the distribution range and shape of the influenced area. The areas of influence maximized on heavy-polluting days for both WBP and SBP emission sources with the total span reaching 804 m and 16 km, respectively; meanwhile, the areas of influence for carcinogenic risk resulting from WBP emission sources were 1.2 and 2.3 times greater than those measured on fine and rainy days, respectively, and 1.8 and 2.9 times greater for SBP emission sources. Compared with WBPs, the total spans of negatively influenced regions resulting from SBP emission sources were 10.4, 12.5 and 19.9 times greater on fine, rainy and heavy-polluting days, respectively. Therefore, carcinogenic risk was the dominant health threat for populations residing close to solvent-consuming industrial emission sources. The findings suggest that newly developed solvents are capable of significantly reducing consequent health threats, nevertheless, they could still pose occasional threats to nearby residents under specific meteorological conditions.     

人工神经网络在台风预报中的应用初探

为了探索人工神经网络应用于台风分类预报的可能性，用具有Ｓ－特特性函数的Ｂ－Ｐ网络对每类台风的标准样本进行训练，由训练结束后的权值和阈值及待预报样本的因子测值，计算出网络输出值，作出台风分类预报。文中的实例表明人工神经网络用于台风预报具有客观性、可行性和实用性。     

Responses of dissolved organic carbon and dissolved nitrogen in surface water and soil to CO2 enrichment in paddy field

Increasing evidences have shown that dissolved organic components are responsible for the significant C and N exports from terrestrial ecosystems to the surrounding aquatic ecosystems and very sensitive to CO₂ enrichment. However, there is still a lack of direct evidence about CO₂-led effects on these components at the ecosystem scale, especially in wetlands. We, therefore, simultaneously investigated the contents of dissolved organic carbon (DOC) and dissolved nitrogen (DN) in the surface water and soil layer in a paddy field under FACE facility in Eastern China. Elevated CO₂ significantly increased the contents of DOC and DN in the surface water by 18.0% and 14.3% on average. Elevated CO₂ also increased DOC content in the soil, but decreased DN content. The contents of DOC and DN in the soil–water interface of 0–1 cm soil layer were on average 22.4% and 47.5% higher than in the 5–15 cm soil layer. Besides, significant higher DOC and DN contents existed in the soil porewater than in the surface water. Due to multiple drainage regime and rainstorm-induced runoffs in rice cropping regions, CO₂-led DOC and DN increments in the surface water may increase C and N exports from paddies to the surrounding aquatic ecosystems under future climate patterns.     

Unraveling the size distributions of surface properties for purple soil and yellow soil

Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of this study was to elucidate the surface properties of particles within targeted size ranges(i.e. 10, 1–10, 0.5–1, 0.2–0.5 and 0.2 μm) for a purple soil(Entisol) and a yellow soil(Ultisol) using the combined determination method. The mineralogy of corresponding particle-size fractions was determined by X-ray diffraction.We found that up to 80% of the specific surface area and 85% of the surface charge of the entire soil came from colloidal-sized particles( 1 μm), and almost half of the specific surface area and surface charge came from the smallest particles( 0.2 μm). Vermiculite,illite, montmorillonite and mica dominated in the colloidal-sized particles, of which the smallest particles had the highest proportion of vermiculite and montmorillonite. For a given size fraction, the purple soil had a larger specific surface area, stronger electrostatic field, and higher surface charge than the yellow soil due to differences in mineralogy.Likewise, the differences in surface properties among the various particle-size fractions can also be ascribed to mineralogy. Our results indicated that soil surface properties were essentially determined by the colloidal-sized particles, and the 0.2 μm nanoparticles made the largest contribution to soil properties. The composition of clay minerals within the diverse particle-size fractions could fully explain the size distributions of surface properties.     

气相色谱/原子发射检测器(GC/AED)在环境化学分析中的应用

概述了GC/AED的原理、特点及其在环境化学分析中的应用,例如,分析地表水中1 μg/L水平的有机氯、有机磷、有机氮和有机硫化物农药。AED可检测C、S、P、Cl、N等25种元素。通常需要几种不相同的常用的选择性检测器才能检测上述农药中不同的原子,这些检测器包括电子捕获检测器、氮磷检测器、火焰光度检测器和霍尔电导检测器。      

Thermochemical pretreatment of meat and bone meal and its effect on methane production

Since the solubilization of meat and bone meal (MBM) is a prerequisite in many MBM disposal approaches, enhancement of the solubilization by means of thermochemical pretreatment was investigated in this study at two temperatures (55°C and 131°C) and six sodium hydroxide (NaOH) concentrations (0, 1.25, 2.5, 5, 10 and 20 g/L). The MBM volatile solid (VS) reduction ratio was up to 66% and 70% at 55°C and 131°C, respectively. At the same temperature, the VS reduction ratio increased with the increase in the dosage of NaOH. The study on the methane (CH₄) production potential of pretreated MBM shows that the addition of NaOH at 55°C did not cause the inhibition of the succeeding CH₄ production process. However, CH₄ production was inhibited by the addition of NaOH at 131°C. The CH₄ production potential was in the range of 389 to 503 mL CH₄/g VS MBM and 464 to 555 mL CH₄/g VS MBM at 55°C and 131°C, respectively.     

含盐废水的生物处理研究进展

含亍废水包括海水直接利用后排放出的废水和许多工业废水,如化工废水、农药废水。因为含盐量高、废水的生物处理具有一定的难度,本文在文献调查的基础上讨论了含盐废水生化处理的可行性、盐对微生物生化特性的影响和国内外对含盐废水生化处理技术和机理研究的进展。