Preparation and emission characteristics of ethanol-diesel fuel blends

The preparation of ethanol-diesel fuel blends and their emission characteristics were investigated. Results showed the absolute ethanol can dissolve in diesel fuel at an arbitrary ratio and a small quantity of water(0.2% ) addition can lead to the phase separation of blends. An organic additive was synthesized and it can develop the ability of resistance to water and maintain the stability of ethanol-diesel-trace amounts of water system. The emission characteristics of 10%, 20%, and 30% ethanol-diesel fuel blends, with or without additives, were compared with those of diesel fuel in a direct injection(DI) diesel engine. The experimental results indicated that the blend of ethanol with diesel fuel significantly reduced the concentrations of smoke, hydrocarbon(HC), and carbon monoxide(CO) in exhaust gas. Using 20% ethanol-diesel fuel blend with the additive of 2% of the total volume, the optimum mixing ratio was achieved, at which the bench diesel engine testing showed a significant decrease in exhaust gas. Bosch smoke number was reduced by 55%, HC emission by 70%, and CO emission by 45%, at 13 kW/1540 r/min. However, ethanol-diesel fuel blends produced a few ppm acetaldehydes and more ethanol in exhaust gas.     

气相色谱法测定环境空气中的乙醛

建立了环境大气中乙醛的气相色谱测定方法。采样效率在９９５以上，回收率为９２．８％－９９．５％，变异系数为２．５６％－３．２４％。当采样体积为１０Ｌ时，最低检出浓度为０．１４ｍｇ／ｍ＾３。     

乙醛对鱼类毒性的实验研究

介绍了实验室乙醛对鲢鱼幼鱼的急性毒性。试验结果表明，乙醛对鲢鱼幼鱼的急性毒性４８ｈＬＣ５０为１４６１８ｍｇ／Ｌ，其安全浓度为１４６２ｍｇ／Ｌ。     

仪化涤纶厂乙醛废气质量浓度的分布规律

通过对仪化涤纶厂乙醛废气污染源的调查及监测，分析了其源强、生产车间及厂区内外的分布规律，并进一步作了该厂乙醛废气对环境影响的预测评价。结果表明，周边地区乙醛废气的质量浓度分布均达到《工业企业设汁卫生标准》的要求。     

苯系物光催化开环降解产物低级醛类的健康效应

采用连续流配气系统,利用氮掺杂TiO2,在UV(4 W,254 nm)光照下光催化降解(PCO)室内甲苯和苯甲醛污染物,运用质子转移反应质谱仪实时检测气相中间产物,应用健康风险评估模型分析甲苯、苯甲醛光催化降解过程的健康效应.结果表明,甲苯和苯甲醛转化率和矿化率较高,但如乙醛和甲醛等低级醛类(VAs)中间产物形成潜在的健康风险,常规的转化率和矿化率指标不能全面表征苯系物的光催化过程的健康风险.乙醛极易在气相积累,是影响健康风险变化的关键;甲醛的摩尔分数稳定在较低水平,但其影响不可忽视.甲苯和苯甲醛降解过程的健康风险指数增大因子(η)随VAs积累而增大,最大值分别为8 499.68和21.43,VAs的贡献率为99.3%和98.3%;光催化降解稳定后η分别为236.09和2.30,VAs的贡献率为97.9%和97.8%;η平均值(30 min)分别为932.86和8.52,VAs的贡献率为98.5%和98.0%.由此提出了以低级醛类健康风险指数增大因子贡献值(ηVAs)表征苯系物光催化安全降解过程的特征评价指标.     

Preparations of TiO2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.     

不同净水工艺对乙醛的控制效果研究

在实验室条件下研究了传统水处理工艺和粉末活性炭吸附、吹脱及臭氧氧化等几种常见应急净水技术对乙醛的处理效果,发现其对水中乙醛的控制效果不佳;活性炭对乙醛吸附效果不佳,导致滤池穿透时间极短,新炭也仅为10 h左右,不足以应对乙醛污染.微生物对乙醛降解作用显著,驯化后的生物活性炭滤池(BAC)13 min内可将水中1.5 mg/L的乙醛降低到标准限值0.05 mg/L以下.水厂在用活性炭滤池中的微生物菌群实验条件下驯化时间约为4～30 h,原有菌落成熟且稳定的活性炭需要的驯化、调整时间反而更长.通过抑制颗粒活性炭表面原微生物活性或人工投加驯化菌种可有效地将驯化时间从30 h左右缩短至4 h以下.     

浙江嘉兴农场大气羰基化合物水平及来源

对浙江嘉兴农场的大气羰基化合物水平进行了研究,利用液相双质谱(LC-MS/MS)进行样品分析,检测出32种羰基化合物.结果表明,甲醛、乙醛、壬醛/2-壬酮和十二醛为最为丰富的羰基化合物,其平均浓度分别为13.99,8.76,7.77,7.13μg/m3,分别占羰基化合物总量的18.29%,11.45%,10.16%,9.32%.光化学反应和植物排放,尤其是水稻的排放,是嘉兴农场大气羰基化合物的主要来源;水稻收割活动还是乙醛和己醛的另一个来源.羰基化合物之间的相关性分析表明,甲醛与乙醛之间有显著线性相关(r=0.58,P0.70,表明庚醛与乙醛及其他高分子的羰基化合物亦有相同来源;十一醛、十二醛、十三醛、辛醛、癸醛和壬醛/2-壬酮之间的线性相关在0.95~0.99范围(P<0.01),表明其来源极为一致.     

广州机动车尾气中乙醛稳定碳同位素特征和排放因子

为了获得机动车排放源中乙醛的δ13C(稳定碳同位素丰度)特征及其影响因素,进行不同负荷下的发动机台架试验,采集不同怠速下的机动车尾气样品. 利用气相色谱-燃烧-同位素比值质谱(GC-C-IRMS)分析乙醛δ13C值,并与ρ(乙醛)进行分析. 结果显示:①在发动机燃烧过程中,乙醛的生成和消除反应同时存在. 在发动机低负荷运行时,乙醛的δ13C分馏值为负(-1.4‰~-0.4‰),表明生成反应占主导;而在高负荷运行时,分馏值为正(0.5‰~1.3‰),表明消除反应占主导. ②乙醛的δ13C值与其质量浓度无明显相关性,主要受发动机燃烧温度和尾气净化装置的影响. 整车尾气中乙醛的δ13C值在-29.1‰～-24.4‰之间,平均值为-26.5‰±1.6‰. 其中,汽油车为-25.9‰~-24.4‰,平均值为-24.9‰±0.5‰;柴油车为-29.1‰~-27.0‰,平均值为-28.0‰±0.6‰. ③南方机动车尾气排放源与植物排放源中的乙醛的δ13C值范围不同,表明δ13C值可用于大气乙醛的源解析. 通过机动车尾气中c(乙醛)/c(CO₂)估算广州汽油车和轻型柴油车乙醛的排放因子,二者分别为(13±16)和(169±106)mg/L.      

Characteristics of odorous carbonyl compounds in the ambient air around a fishery industrial complex of Yeosu, Korea

In this study,the amounts of odorous carbonyl compounds(OCCs) including acetaldehyde(Acet-A),propionaldehyde(Pron-A),butylaldehyde(Buty-A),iso-valeric aldehyde(Iso-Vale-A) and n-valeric aldehyde(N-Vale-A) emitted from a fishery industrial complex near the exhibition facilities of "Expo 2012 Yeosu Korea" were measured.Acet-A was found to be the most abundant OCC,and the total concentrations of the OCCs were the highest in the summer.However,due to vehicular exhaust and photochemical reactions,the concentrations of some of the OCCs presented their highest levels in the fall.A significant correlation between Acet-A and Buty-A was found at the major fishery facilities(r = 0.816,p = 1.87E-15,n = 60) and at the border areas(r = 0.809,p = 3.40E-12,n = 48) of this fishery industrial complex.The concentrations of OCCs at the border areas were not worse than those at the urban areas in other places,indicating that the concentrations of ambient OCCs at the border areas were not greatly influenced by manmade activities.