新型螯合型表面活性剂增溶菲的热力学和动力学研究

采用批平衡试验法,研究了新型螯合型表面活性剂N-十二酰基乙二胺三乙酸钠(N-LED3A)增溶菲的性能,并探讨了其增溶热力学和动力学特征.结果表明:N-LED3A可有效增溶菲,菲的表观溶解度S*w及其在表面活性剂单体和胶束相的分配系数Kmn和Kmc均随温度升高而增大;N-LED3A的临界胶束浓度(CMC)随温度的升高(15、25、35、45℃)呈现先减小后增大的趋势;菲在N-LED3A单体/水、胶束/水的表观摩尔分配焓变ΔH*mm、ΔH*mc分别为18.30、13.12 kJ·mol-1,菲在水、N-LED3A单体和胶束中的表观摩尔溶解热分别为18.87、37.17和31.99 kJ·mol-1,均为吸热过程,故温度升高有利于菲在N-LED3A单体和胶束中的分配作用,菲在水、N-LED3A单体和胶束中的溶解量随温度升高而增大。动力学方程拟合结果表明,一级动力学方程最适合描述N-LED3A对菲的增溶过程.     

Removal of hydrophobic volatile organic compounds with sodium hypochlorite and surfactant in a co-current rotating packed bed

A co-current flow rotating packed bed was applied to remove volatile organic compounds(VOCs) by sodium hypochlorite(Na Cl O) and surfactant(sodium dodecyl benzene sulfonate,SDBS) from air stream. Xylene was used as a model VOC herein. The effect of p H,concentration of Na Cl O and SDBS solution, liquid flow rate, gas flow rate and rotational speed on xylene removal efficiency and overall mass transfer coefficient(KGa) were discussed. Then, a correlation for KGa of the co-current rotating packed bed was proposed by fitting the experimental data of KGa and independent variables of liquid/gas ratio,rotational speed, p H, Na Cl O concentration and treatment time, which was in good agreement with the experimental data(the deviation ≤± 30%).     

医化行业挥发性有机废气（VOCs）排放特征及防治对策

为了防治医化行业挥发性有机废气（VOCs）环境污染,推动医化行业的可持续发展,本文通过全面调查VOCs的排放源头、排放方式、防治措施,对比分析了各种末端处理技术的优劣,确定了医化行业有机废气（VOCs）防治的有效方式。     

广州番禺大气成分站挥发性有机物的污染特征

应用GC/FID在线挥发性有机物(VOCs)检测仪,于2011年6月~2012年5月在中国气象局广州番禺大气成分观测站进行了1a的连续监测,获得了具有高时间分辨率的VOCs组成、含量及其时间变化规律.结果表明:VOCs浓度月变化范围是(40.99~65.400)×10-9,月平均浓度48.10×10-9,冬季VOCs浓度高于夏季.VOCs日浓度变化范围是(35.10~59.13)×10-9.VOCs组分随季节变化所占比例不同,烷烃、烯烃和芳香烃全年平均所占比例分别为58%、16%和26%.采样点在7月份没有周末效应,而在12月份表现出显著周末效应.国庆长假期间的大气VOCs浓度比国庆节放假前、后均有大幅度降低,降幅分别达到39.3%和56.7%.采样点的大气VOCs浓度与风速呈负相关性.当风向为NNE、NE和SSW时,风速较大,VOCs的浓度较低;当风向为WNW和ENE时则相反.由于夏季温度高使溶剂挥发性和植物排放增强,所以导致BTEX(苯、乙苯、甲苯和二甲苯)和异戊二烯的浓度在夏季明显高于冬季.     

大气中挥发性有机化合物(VOCs)的人为来源研究

在2002年春、夏、秋、冬四季对环境大气中挥发性有机化合物的组成和变化规律进行了研究,在此基础上运用CMB8.0受体模型对各类污染源进行了源解析,得到受体点各人为污染源的年平均贡献率分别为:汽车尾气62%,汽油挥发9%,石油液化气10%,涂料6%,石油化工6%,未知源6%.对不同物种贡献的分析显示,环境大气中的乙烯、苯和甲苯等化合物主要来自于汽车尾气的排放,异戊烷来自于汽油的挥发,石油液化气、涂料、石油化工分别对大气中的异丁烷、正己烷和2,4-二甲基戊烷贡献量最大.     

中国室内挥发性有机物污染特征

近年来室内空气污染问题频发,已引起全社会的广泛关注.挥发性有机物(volatile organic compounds,VOCs)是室内空气的主要污染物之一,其成分复杂,来源广泛,严重威胁人体健康.本文综述了中国近十年来室内VOCs在来源、浓度水平、影响因素及健康评价方面的研究进展.研究表明,室内建筑装修材料、人类活动及室外污染等来源都会影响VOCs的室内浓度;中国住宅内甲醛、苯等VOCs污染普遍存在,家具市场是甲醛污染最高的公共场所;VOCs浓度受到温湿度、通风和装修时间等因素影响;中国室内部分VOCs对人体健康影响评估值超过美国环保署可接受水平.调查更全面的室内VOCs数据,探索对各类因素影响机制,提出更有效降低VOCs对人体健康影响的措施将是未来室内空气治理重点发展方向.     

大气中挥发性有机物在线监测系统

一种新型的监测大气中挥发性有机物（包括含氧挥发性有机物）的在线监测系统被研制,即将超低温冷阱捕集-热解析装置与气相色谱-质谱仪联用.其分析方法是大气样品经除水、除O3后以60 mL·min-1的流速通过温度为-150℃的超低温冷阱捕集5min,然后样品在110℃下解析后进入GC-FID/MS系统进行分析,时间分辨率为1h.系统使用混和标气进行标定.目标化合物定量曲线的R2值为0.9137~0.9998,相对标准偏差(RSD)均小于10%.将系统与相关商业化的VOC在线监测仪器进行比对,对于相同目标化合物进行分析,其相关系数r在0.7412~0.9620之间.     

环境中挥发性有机物监测及分析方法

挥发性有机物(VOCs)是一类重要的环境污染物,严重威胁着环境和人类健康。随着VOCs问题的日趋突出,关于VOCs监测技术的研究也越来越多,检测技术逐渐完善。本文对大气中VOCs的监测技术进行了详细的综述,重点介绍了气相色谱-质谱、高效液相色谱等离线检测方法和质子转移反应质谱法在线监测方法。此外,本文分析了各种采样方法及仪器检测技术的优势与不足,旨在为大气VOCs的监测与研究起到一定的指导作用。     

Ambient volatile organic compounds pollution in China

Owing to rapid economic and industrial development, China has been suffering from degraded air quality and visibility. Volatile organic compounds (VOCs) are important precursors to the formation of ground-level ozone and hence photochemical smog. Some VOCs adversely affect human health. Therefore, VOCs have recently elicited public concern and given new impetus to scientific interest. China is now implementing a series of polices to control VOCs pollution. The key to formulating policy is understanding the ambient VOCs pollution status. This paper mainly analyzes the species, levels, sources, and spatial distributions of VOCs in ambient air. The results show that the concentrations of ambient VOCs in China are much higher than those of developed countries such as the United States and Japan, especial benzene, which exceeds available standards. At the same time, the ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) of various VOCs are calculated. Aromatics and alkenes have much higher OFPs, while aromatics have higher SOAFP. The OFPs of ambient VOCs in the cities of Beijing, Guangzhou and Changchun are very high, and the SOAFP of ambient VOCs in the cities of Hangzhou, Guangzhou and Changchun are higher.     

人体呼出气中内源性挥发性有机物筛选研究

人体代谢产生的内源性挥发性有机物（VOCs）可用作健康状况的标志物.本研究选择17~26岁无呼吸系统疾病的高校学生（73人）作为观察对象,使用气相色谱-火焰离子化检测器/质谱联用仪（GC-FID/MS）分析收集到的呼出气样本,对呼出气中VOCs的种类、浓度进行研究,发现了其5种卤代物的浓度高于室内浓度,其次是室外浓度.其中,在人体呼出气中1,1-二氯乙烯的浓度为室内浓度的近20倍,是室外浓度的近300倍,人体呼出气是环境中1,1-二氯乙烯的一个重要源.定量分析健康人呼出气,对比其与环境空气样本的浓度差异,并进行统计学检验,共筛选出1,1二氯乙烯、丙酮、1-己烯、甲基环己烷、2-戊酮、反-2-戊烯、2,4-二甲基戊烷、3-戊酮、四氯乙烯、对二氯苯、间二氯苯11种特征性内源性VOCs.     

两种介孔分子筛动态吸附VOCs的研究

采用模板剂法制备了孔道规整、大比表面积的2种介孔分子筛MCM-41和SBA-15,并以甲苯、二甲苯、三甲苯为吸附对象,考察了介孔分子筛动态吸附VOCs的性能.结果表明,增加VOCs分子尺寸和浓度,降低床层温度可大幅提高介孔分子筛吸附性能.SBA-15由于介孔壁上的微孔结构适合吸附低浓度、小分子VOCs;MCM-41更适合吸附高浓度、大分子VOCs.TPD脱附试验表明,VOCs在介孔材料表面150℃下就能基本脱附完全.     

The ignored emission of volatile organic compounds from iron ore sinter process

Iron ore sintering is a major source of gaseous and particulate pollutants emission in iron smelt plant. The aim of present study is to characterize the volatile organic compounds(VOCs) emission profiles from iron ore sintering process. Both sinter pot test and sinter simulation experiment were conducted and compared. Out results showed that sinter process produced large quantity of VOCs together with NOxand SO_2. VOCs and NO were produced simultaneously in sinter pot test from 3 to 24 min after ignition, flowed by SO_2 production from 15 min to the end of sintering. Total VOCs(TVOC) concentration in sinter flue gas was affected by the coal and coke ratio in sinter raw material. The maximum TVOC concentration was 34.5 ppm when using 100% coal as fuel. Sinter simulation experiments found that the number of VOCs species and their concentrations were found by sinter temperature. The largest VOCs species varieties were obtained at 500 °C. Benzene, toluene,xylene and ethylbenzene were major VOCs in sinter flue gas based on the results from both simulation test and sinter pot. It thus demonstrated that in addition to NO_x, SO_2 and metal oxide particles, sinter flue gas also contained significant amount of VOCs whose environmental impact cannot be ignored. Based on our work, it is timely needed to establish a new VOC emission standard for sinter flue gas and develop advanced techniques to simultaneously eliminate multi-pollutants in iron ore sinter process.     

Remove volatile organic compounds (VOCs) with membrane separation techniques

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国六重型柴油车挥发性有机物排放特性

选取5辆典型国六重型柴油车,进行基于C-WTVC的挥发性有机物(VOCs)排放测试,分析了包括7种苯系物以及14种醛酮类物质的比排放量.结果表明,甲苯、苯、苯乙烯是国六重型柴油车苯系物排放的主体物质,占总量的60％～86％;而甲醛、乙醛、苯甲醛是醛酮污染物的主要物质,占总量的72％～87％.在同时包含市区、市郊和高速综...     

中国挥发性有机物（VOCs）排放源成分谱研究进展

我国VOCs排放来源多、排放成分复杂.排放源成分谱是识别VOCs排放源特征的基本信息,对开展我国大气复合污染研究及制定污染控制策略具有重要意义.本文在介绍排放源成分谱的测量方法和总结我国排放源成分谱测量结果的基础上,阐述了典型排放源VOCs成分谱组分特征.不完全燃烧产物(烯烃和醛酮类)是机动车尾气的重要组分,烯烃在我国油品挥发成分谱中的比例较高,含氧VOCs在溶剂使用源和燃烧排放源中不容忽视,化学组分复杂是工业排放的重要特征.文章还指出了源谱研究的不足之处,主要包括源谱采集与测试方法不规范、测量结果质量难以保证及评价、含氧VOCs组分关注不够、工业排放源成分谱缺失等.从源谱的测量方法、测量组分和数据后处理等方面进行规范化,继续加强机动车排放研究,开展石油化工等工业源谱测量,构建我国本地化VOCs源谱数据库将是今后重要研究工作.     

医院和实验室室内环境中挥发性有机污染物的比较

分别采集了医院和实验室环境空气样品,通过GC-MS/FID对样品进行定性分析.共定性检测出116种挥发性有机物(VOCs).在这两类环境中检出频次较高的VOCs物种包括乙烷、丙烷、正丁烷等烷烃;乙烯、丙烯、1-丁烯等烯烃;苯、甲苯、乙苯等芳香烃;氯甲烷、二氯甲烷等卤代烃和丙酮等含氧有机物.在实验室中经常使用的试剂如正己烷、甲苯、乙醇、丙酮等呈现较高的水平,高于室外1~3个数量级.在医院的部分候诊区中检出较高浓度的甲苯、乙苯、二甲苯,需要引起关注.     

Significant contribution of spring northwest transport to volatile organic compounds in Beijing

High values of ozone (O₃) occur frequently in the dry spring season; thus, understanding the evolution characteristics of volatile organic compounds (VOCs) in spring is of great significance for preventing O₃ pollution. In this study, a total of 101 VOCs from April 16 to May 21, 2019, were quantified using an online gas chromatography mass spectrometer/flame ionization detector (GCMS/FID). The results indicated that the observed concentration of total VOCs (TVOCs) was 30.4 ± 17.0 ppbv, and it was dominated by alkanes (44.3%), followed by oxygenated VOCs (OVOCs) (17.4%), halocarbons (12.7%), aromatics (9.5%), alkenes (8.2%), acetylene (5.3%) and carbon disulfide (2.5%). The average mixing ratio of VOCs showed obvious diurnal variation (high at night, low during daytime). We conducted a source apportionment study based on 32 major VOCs using positive matrix factorization (PMF), and coal + biomass burning (25.2%), diesel exhaust (16.0%), gasoline exhaust + evaporation (17.4%), secondary + long-lived species (16.7%), biogenic sources (4.3%), industrial emissions (9.3%) and solvent use (11.2%) were identified as major sources of VOCs. In addition to local emissions, most of the atmospheric VOCs were derived from long-distance air masses (65.7%), and the average mixing ratio of VOCs in the northwest direction was 29.4 ppbv. Combined with the results of the potential source contribution function (PSCF) indicate that research should focus on the local emissions of combustion, transportation sources and solvents usage to control atmospheric VOCs. Additionally, transmission of the northwest air mass is an important component that cannot be ignored during spring in Beijing.     

上海秋季大气挥发性有机物特征及污染物来源分析

综合分析了上海地区秋季典型月份挥发性有机物(VOCs)及其他痕量气体的污染水平及特征,VOCs平均小时浓度为63.64′10-9,非甲烷碳氢化合物(NMHCs)占挥发性有机物总量的67.43%;通过对VOCs物种浓度及特征比值分析发现研究区域大气老化现象明显;结合区域后向气流轨迹分析,考察了不同来源气流对区域污染特征的影响,发现陆地传输气流乙烷/乙炔(E/E)值较海上传输气流低,而两者的苯/甲苯(B/T)值没有明显差异.     

工业源VOCs污染防控对策案例研究

挥发性有机物(VOCs)已经与氮氧化物(NOx)、颗粒物等成为我国典型城市群的主要大气污染物,其中工业源VOCs排放量大,是珠江三角洲地区影响最大的一类VOCs排放源。由于VOCs种类繁多,来源及转化生成臭氧的机制复杂,为解决此类复杂的VOCs污染问题,文章以东莞市作为珠三角典型区域代表,归纳总结了VOCs防控措施,分析了工业源VOCs治理的难点,有针对性地提出相关的有效对策建议,以期为大气环境质量管理和决策提供有益帮助,也为全国其他城市的VOCs污染防控提供借鉴。     

孔径调变对MCM-41分子筛吸附VOCs性能的影响

采用3种不同碳链长度的季铵盐表面活性剂C_nTAB(n=8,12,16)为模板剂,分别合成8-MCM-41、12-MCM-41和16-MCM-41介孔分子筛,并以甲苯、邻二甲苯、均三甲苯为吸附对象,考察了介孔分子筛动态吸附VOCs的性能.结果表明,通过减少表面活性剂的碳链长度,可以成功地把MCM-41分子筛的孔径调变为4.1、3.2和2.4 nm.吸附实验结果表明,当MCM-41孔径减小时,其对低浓度甲苯、邻二甲苯的吸附量大幅上升,均三甲苯存在孔道扩散效应,其吸附量增加不明显.吸附等温线表明,在2.4 nm孔道内,3种芳烃分子均属于典型的Langmuir单分子层吸附;当孔径大于2.4 nm时,芳烃分子出现明显的多层吸附和毛细凝聚现象.