Regeneration of granular activated carbon loaded with explosives

Granular activated carbon (GAC) loaded with trinitrotoluene (TNT) and nitrobenzene (NB) were subjected to different atmospheres, such as nitrogen, oxygen, air, steam and an air-steam mixture, at varying temperatures and for different time intervals for regeneration. The air-steam mixture proved to be the best regenerating media for the explosive-loaded GACs. The regeneration of the activated carbon was found to be above 85% for TNT and above 90% for NB loaded carbons.     

典型恶臭有机污染自动监测技术与应用探究

对比6种主流有机硫自动监测仪的4种有机硫混标测试结果,表明80%仪器的性能指标能满足国家恶臭排放标准中厂界监测的定量要求。复杂环境适用性研究显示,有机硫化物间测定影响相对较小,高浓度标气有残留,定性受到常见挥发性有机物中个别物质干扰。优选3种检测器为FPD的仪器现场连续实测,结果表明甲硫醇、甲硫醚、二甲二硫醚和二硫化碳为石化园区的有机硫常检出物种;3种仪器的监测数据可较好地反映该石化园区空气恶臭污染特征。     

三点比较式臭袋法测定环境中臭气浓度

就三点比较式臭袋法在测定环境空气臭气浓度时应注意的现场踏勘、采样点的选择、采样次数、配气、嗅辨过程,以及臭气浓度计算等问题进行探讨,使该方法更加完善、简便.     

Estimation of shipping emissions in Candarli Gulf, Turkey

Ships are significant air pollution sources as their high powered main engines often use heavy fuels. The major atmospheric components emitted are nitrogen oxides, particulate matter (PM), sulfur oxide gases, carbon oxides, and toxic air pollutants. Shipping emissions cause severe impacts on health and environment. These effects of emissions are emerged especially in territorial waters, inland seas, canals, straits, bays, and port regions. Candarli Gulf is one of the major industrial regions on the Aegean side of Turkey. The marine environment of the region is affected by emissions from ships calling to ten different ports. In this study, NO _x , SO₂, CO₂, hydrocarbons (HC), and PM emissions from 7,520 ships are estimated during the year of 2007. These emissions are classified regarding operation modes and types of ships. Annual shipping emissions are estimated as 631.2 t year^???1 for NO _x , 573.6 t year^???1 for SO₂, 33,848.9 t year^???1 for CO₂, 32.3 t year^???1 for HC, and 57.4 t year^???1 for PM.     

基于区域环境空气质量和碳排放数据的减污降碳协同效果评估

化石燃料燃烧产生的温室气体与大气污染物具有同根同源性,但具体治理中减污降碳的协同效果尚不明确。以浙江省11个设区市为研究样本,对环境空气质量和二氧化碳(CO₂)排放数据进行分析研究,结果显示：2016—2020年浙江省环境空气质量持续改善,但CO₂排放总量仍处于增长阶段。11个设区城市PM_2.5年均浓度降幅在26%～41%之间,二氧化氮(NO₂)年均浓度下降趋势不明显,大部分城市呈现碳排放增加、NO₂浓度下降的特征,只有杭州和温州两市呈现碳排放总量和NO₂、PM_2.5浓度协同下降的趋势。因子相关性分析结果表明,各设区市呈现NO₂浓度与碳排放相关性较大、协同性强,PM_2.5浓度与碳排放相关性较小的特点。进一步通过减污降碳协同定量评价分析表明,浙江地区在环境空气质量改善和温室气体减排已表现出一定成效,但各设区市因产业结构、环境基础条件、协同程度等不同导致减污降碳综合绩效有明显差异。从源头减排实现...     

温室气体光声光谱检测系统的建立及效果分析

“双碳”目标下,温室气体在线长期稳定监测技术是全面掌握温室气体排放及其环境、气候效应,并预测未来变化趋势的重要保障。为了实时在线监测工业生产现场等环境温室气体浓度及其变化趋势,及时采取相应措施,在分析光声光谱信号产生机理及多组分气体混合监测原理的基础上,根据温室气体的主要成分,分析其吸收光谱特性,基于光声光谱的多组分温室气体的定性和定量监测技术,搭建温室气体光声光谱在线监测实验平台,分析监测器内部噪声和环境温度、湿度等外部影响因素,并通过现场测试,分析试验数据,应用吸附法降低内外部因素的影响。结果表明,对称安装传声器和非共振式光声腔能有效削弱外部噪声对测试结果的影响;空气净化器能降低空气中水蒸气和其他气体对测试结果的影响;低、高浓度混合气体监测结果偏差均小于0.5,与GC测试结果偏差小于10%。应用光声光谱技术的环境温室气体监测技术监测范围宽,选择性好,且监测精度达10^-6,适用于环境温室气体浓度在线监测。     

Greenhouse gas emissions from forestry,land-use changes,and agriculture in Tanzania

The purpose of the study was to identify and quantify anthropogenic sources and sinks of greenhouse gases from forestry, land-use changes and agriculture in Tanzania. The 1990 inventory revealed that, in the land-use sector, methane (CH₄) and carbon dioxide (CO₂) are the primary gases emitted. Enteric fermentation in livestock production systems is the largest source of CH₄. Although deforestation results in greenhouse gas emissions, the managed forests of Tanzania are a major CO₂ sink.     

Study of odor compounds in gaseous effluents generated during production of poultry feather and viscera meal using headspace solid phase microextraction

This work reports the screening and characterization of odor compounds in gaseous effluents generated during the production of poultry feather and viscera meal, the by-products of the poultry meat industry. Chemical analysis was carried out by solid phase microextraction in the headspace (HS-SPME) mode. Exhaust air of thermal processing of poultry feather and viscera were sampled online from a bench-scale digester, condensed, and collected in sampling flasks. Both volatile and semivolatile organic compounds present in the condensed gases were extracted under agitation at constant temperature. The extracts were analyzed with a gas chromatograph coupled to a mass spectrometric detector (GC/MSD). The identification of compounds was carried out by comparing the mass spectra obtained with those from the Wiley library and quantification was accomplished through authentic analytical standards. For the determination of the best extraction conditions and analysis, extraction fibers of different coatings and polarities were tested: divinylbenzene/carboxen/polydimethyilsiloxane (DVB/CAR/PDMS), carbowax/divinylbenzene (CW/DVB), and polydimethylsiloxane (PDMS) and chromatography columns of different polarities: DB-WAX (polar) and DB-5 (nonpolar). The best extraction conditions and analysis of the compounds of interest were obtained by the use of the SPME fiber with DVB/CAR/PDMS coating and analysis by GC/MSD with polar capillary column. Several carboxylic acids were identified, as well as mercaptans, amines, and aldehydes of great environmental importance.     

Methods for determination of elemental carbon in ambient air

A few analytical methods of elemental carbon determination are described. The purpose of the work is to choose the best method for determination of its content in dust suspended in air in industrial regions. The reflectance and chromatographic methods were investigated. It was shown that the reflectance methods could be used only when the particle size and form of elemental carbons constant. The chromatographic method, which includes the step of combustion of the sample in oxygen and chromatographic determination of evolved CO₂ is recommended, since it is independent of the form of carbon. Organic carbon is removed from dust samples by extraction with benzene-methanol mixture.     

Experimental and Numerical Verification of Similarity Concept for Dispersion of Car Exhaust Gases in Urban Street Canyons

In urban conditions, car exhaust gases are often emitted inside poorly ventilated street canyons. One may suppose however that moving cars can themselves produce a certain ventilation effect in addition to natural air motions. Such ventilation mechanism is not sufficiently studied so far. A similarity criterion relating the vehicle- and wind-induced components of turbulent motion in an urban street canyon was proposed in 1982 by E. J. Plate for wind tunnel modelling purposes. The present study aims at further evaluation of the criterion and its applicability for a variety of wind and traffic conditions. This is accomplished by joint analyses of data from numerical simulations and wind tunnel measurements.     

Polycyclic aromatic hydrocarbons in bulk PM2.5 and size-segregated aerosol particle samples measured in an urban environment

To analyze polycyclic aromatic hydrocarbons (PAHs) at an urban site in Seoul, South Korea, 24-hr ambient air PM_2.5 samples were collected during five intensive sampling periods between November 1998 and December 1999. To determine the PAH size distribution, 3-day size-segregated aerosol samples were also collected in December 1999. Concentrations of the 16 PAHs in the PM_2.5 particles ranged from 3.9 to 119.9 ng m⁻³ with a mean of 24.3 ng m⁻³.An exceptionally high concentration of PAHs(∼120 ng m⁻³) observed during a haze event in December 1999 was likely influenced more by diesel vehicle exhaust than by gasoline exhaust, as well as air stagnation, as evidenced by the low carbon monoxide/elemental carbon (CO/EC) ratio of 205 found in this study and results reported by previous studies. The total PAHs associated with the size-segregated particles showed unimodal distributions. Compared to the unimodal size distributions of PAHs with modal peaks at < 0.12 μm measured in highway tunnels in Los Angeles (Venkataraman and Friedlander, 1994), four- to six-ring PAHs in our study had unimodal size distributions, peaking at the larger size range of 0.28–0.53 μm, suggesting the coagulation of freshly emitted ultrafine particles during transport to the sampling site. Further, the fraction of PAHs associated with coarse particles(> 1.8 μm) increased as the molecular weight of the PAHs decreased due to volatilization of fine particles followed by condensation onto coarse particles.     

硫化学发光检测器-气相色谱法测定废气中挥发性硫化物

采用硫化学发光检测-宽口径石英毛细管柱气相色谱法,建立了废气中羰基硫、硫化氢、二硫化碳、甲硫醇、乙硫醇、甲硫醚、乙硫醚、丙硫醇、异丙硫醇、噻吩及二甲二硫等11种挥发性硫化物的分析方法。硫化学发光检测器的灵敏度、选择性及线性范围均优于传统的火焰光度检测器。进样体积为0.2 ml时,硫化物的检出限为0.03～0.1 mg/m3。实际样品5次测定的相对标准偏差小于5.1%,加标回收率为83.7%～108.8%。测定了某炼油厂酸性水罐尾气、污油罐尾气及瓦斯气中挥发性硫化物,为其恶臭控制与治理提供检测手段和基础数据。     

Assessment using CFD of the wind direction on the air discharges caused by natural ventilation of a poultry house

Air inside poultry houses must be removed on a regular basis to prevent excess of heat, particles and noxious gases that can imperil animals. To cope with this issue, natural ventilation could be an effective method when assisted by accurate predictions. This study investigates air discharges caused by natural ventilation of a poultry house by means of a three-dimensional computational fluid dynamics (CFD) model. It solves the governing equations of momentum, heat and mass transport, radiative transfers and animal-generated heat. Wind directions of 0°, 36° and 56° (0° corresponds to a wind blowing perpendicular to the ridgeline) were investigated; the CFD model predictions achieved a RMSE of 1.2 °C and 0.6 g[H₂O] kg^?1 [dry air] for internal temperature and absolute humidity, respectively, when air blew with an angle of 36°. Air renewal rates (ARR) were 39.5 (±?1.9), 34.9 (±?2.2) and 33.6 (±?1.7) volumes of the building per hour, when air blew at 0°, 36° and 56°, respectively. Such ARR predictions served to know how the gases contained in air would likely spread downstream from the building in order to define regions of potentially high gas concentration that could endanger neighbouring habitable facilities.     

The impact assessment of Diwali fireworks emissions on the air quality of a tropical urban site, Hyderabad, India, during three consecutive years

Diwali is one of the largest festivals for Hindu religion which falls in the period October–November every year. During the festival days, extensive burning of firecrackers takes place, especially in the evening hours, constituting a significant source of aerosols, black carbon (BC), organics, and trace gases. The widespread use of sparklers was found to be associated with short-term air quality degradation events. The present study focuses on the influence of Diwali fireworks emissions on surface ozone (O₃), nitrogen oxides (NO _x ), and BC aerosol concentration over the tropical urban region of Hyderabad, India during three consecutive years (2009–2011). The trace gases are analyzed for pre-Diwali, Diwali, and post-Diwali days in order to reveal the festivity’s contribution to the ambient air quality over the city. A twofold to threefold increase is observed in O₃, NO _x , and BC concentrations during the festival period compared to control days for 2009–2011, which is mainly attributed to firecrackers burning. The high correlation coefficient (~0.74) between NO _x and SO₂ concentrations and higher SO₂/NO _x (S/N) index suggested air quality degradation due to firecrackers burning. Furthermore, the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observation-derived aerosol subtyping map also confirmed the presence of smoke aerosols emitted from firecrackers burning over the region. Nevertheless, the concentration level of pollutants exhibited substantial decline over the region during the years 2010 and 2011 compared to 2009 ascribed to various awareness campaigns and increased cost of firecrackers.     

环境空气中异味物质的监测、评价与溯源

针对环境空气中异味物质及其特点,从嗅辨法和成分浓度分析法2个方面,介绍了异味物质的监测方法,并比较了各方法的适用性。从臭气浓度、强度、恶臭厌恶度、相对气味活度值以及模型预测等方面,描述了异味物质特有的评价方法;从对照标准限值、臭氧生成潜势以及健康风险评价等方面,描述了异味物质普适性评价方法。指出可通过实地调查与监测、污染谱图和源解析模型等方法识别异味物质的来源。提出了环境空气异味的监测调查建议,包括采用多种技术、提高异味物质的快速初辨能力以及监测水平,研制更多的方法标准和控制标准、科学监管异味污染物等。     

Application of impregnated filters to determination of smoke and ammonia

Whatman No. 1 filters impregnated with a 3% solution of oxalic acid in ethanol which are used for elimination of ammonia from the air stream before entering the absorber for collecting SO₂, were tested for a possible application (a) in the spectrophotometric determination of ammonia with Nessler's reagent and (b) in the reflectometric determination of smoke. It was shown that impregnated filters were as suitable for the determination of ammonia as absorbing solution and as applicable for smoke measurement as untreated filters. Further, the advantage of using impregnated filters for sampling ammonia lies in avoiding the interference of organic vapours which may occur, if absorbing solution is used.     

An Assessment on Variation of Sulphur Dioxide and Particulate Matter in Erzurum (Turkey)

Sulphur dioxide and PM₁₀ levels are investigated in Erzurum during the periods of 1990–2000 heating season to assess air pollution level. For that reason, emissions of sulphur dioxide and particulate matter were calculated by using consumption of fuels and Turkish emission factors. These emission values were evaluated together with air pollution levels, which were measured at six stations in Erzurum atmosphere during 1990–2000 winter periods. Results reveal that in 1990–1994 heating period, there is an increasing trend in the emissions and air pollution levels over Erzurum, and the air quality limits were not met. The daily 24 h limit (short-term limit) was exceeded 127 days in 1992–1993 winter period. The reason for this increase was found to be the switching to use of low-quality fossil fuels instead of cleaner ones. Results also indicated that there was a considerable decrease in emissions of air pollutants and air pollution levels after 1995. This can be explained by the consumption of more high-quality fossil fuels. The correlation coefficient of SO₂ with PM₁₀ is obtained as r² = 0.85, which is a high value supporting the idea that both pollutants are emitted from the same source.     

Adsorption characteristics of a phenoxy acetic acid herbicide on activated carbon

The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) by two powdered coal activated carbons was studied in aqueous solution. The modelling of the adsorption equilibrium showed that the adsorption of 2,4-D fitted a Langmuir isotherm. Adsorption was influenced by the activated carbon type, adsorbent concentration and solution characteristics. The adsorption was found to decrease with an increase in pH over the range 1.5-9. Maximum adsorption occurred at pH approximately 2.5, which corresponds to the 2,4-D pKa value. The amount of 2,4-D adsorbed was also found to depend on the NaCl concentration.     

固相萃取-气相色谱质谱联用法测定地表水中藻致嗅味物质

选用HLB固相萃取小柱进行富集,用二氯甲烷进行洗脱,优化了固相萃取过程,建立了固相萃取-气相色谱质谱法测定地表水中7种藻致嗅味物质的方法,浓度在0.004~0.1 mg/L范围内线性关系良好,具有较高的灵敏度和精密度,方法检出限为1×10-6~2×10-6mg/L,加标回收率为85.9%~108.6%,适用于地表水中嗅味物质的检测。     

毛细管柱气相色谱法测定环境空气中1,2-二氯乙烷

采用毛细管柱气相色谱法测定环境空气中的1,2-二氯乙烷,用活性碳吸附,二硫化碳解析,FID检测器分析.方法在0 mg/L～311mg/L范围内线性良好,当采样体积为20 L时,最低检出质量浓度为0.006 mg/m3,标准溶液平行测定的RSD≤2.2%,加标回收率为98.4%～101%.