柿树被日本龟蜡蚧危害后挥发物的变化及其对红点唇瓢虫的引诱作用

研究了柿树(DiospyroskakiL.f.)受日本龟蜡蚧(CeroplastesjaponicusGreen)危害后,体内释放出的挥发性物质对天敌昆虫红点唇瓢虫(ChilocoruskuwanaeSilvestri)的招引作用.Y形嗅觉仪测定结果表明,瓢虫趋向受害枝叶的百分率为74.17%,明显大于趋向未受害枝叶的20.00%,t检验证明,二者间差异极显著;而受害轻微枝叶挥发物对红点唇瓢虫的诱导作用与未受害枝叶的诱导效果相比没有显著差异;说明日本龟蜡蚧对柿树的危害可诱导树体挥发性物质发生改变,增加了对红点唇瓢虫的引诱作用.经气相色谱/质谱联用仪(GC/MS)分析发现,柿树未受害枝叶挥发物共有29种组分,烃类物质的相对含量占92.98%;受害枝叶释放出的挥发物组分有32种,烃类物质的相对含量增加到97.15%,另外减少了3种醇类化合物和2种烷烃类化合物,同时合成了8种新的组分,包括4种烃类、3种萜类和1种酮类.这些新合成的化合物极有可能在不同程度上参与了对瓢虫的招引作用.本文揭示了柿树受日本龟蜡蚧危害后,诱导其挥发出对天敌昆虫有引诱作用的化学信息素,为进一步试验确定有效成分和人工筛选模拟引诱剂,开辟生物防治新途径提供了基础依据.图1表2参16     

TiO2纳米粒子光催化氧化室内挥发性有机污染物甲苯的研究

利用溶胶凝胶法制备了粒径约为13nm、晶型为锐钛矿相和金红石相混晶的TiO2光催化剂,并且利用此催化剂对室内空气中主要的挥发性有机污染物甲苯进行了光催化降解研究.对不同的催化剂用量、光强、甲苯的初始浓度以及氧气的存在对光催化反应速率的影响进行了研究.结果表明,光催化降解甲苯的反应符合假一级动力学方程;光强与光催化降解甲苯的反应速率常数之间呈指数关系;随着初始浓度的增加,光催化反应速率常数降低,二者之间存在线性关系;氧气的存在加快了光催化降解甲苯的速率;对于光催化降解初始浓度为37.6μmol·L-1的甲苯而言,催化剂的最佳使用量为0.20～0.30g.     

吹扫-捕集气相色谱法测定水中有机化合物

研究建立了吹扫 捕集法富集样品 ,利用HP 1大口径厚液膜通用型熔融石英毛细管柱 ( 30m× 0 .53mm× 2 .6 5μm) ,ECD检测器 ,同时测定水中 8种挥发性卤代烃及氯代苯的方法 ,确定了最佳吹扫 捕集条件。结果表明 :水样体积为 5mL时 ,标准偏差 <0 .0 5μg/L ,变异系数 <3.0 % ,加标回收率为 97.0 %～ 10 5% ,8种物质的最低检测限在 0 .0 3～ 0 .13μg/L之间     

顶空/气相色谱法测定土壤中挥发性芳烃

采用顶空/气相色谱法(HS/GC)对土壤中挥发性芳烃顶空前处理条件、气相色谱分离、定性和定量分析条件进行了研究,优化了土壤中挥发性芳烃分析的项空前处理条件和气相色谱分离条件,分析了方法的检出限、精密度及回收率等质量控制参数.在最佳条件下,方法检出限大多数小于2.0 μ/kg(以2 g样品计),精密度小于15%,回收率为90%～110%之间.     

城市污水处理过程中恶臭气体释放的研究进展

长期以来,我国城市污水处理相关工作人员职业病频发,与城市污水处理过程中会释放出大量的有毒有害气体有重要关系,我国现有的《城镇污水处理厂污染物排放标准》对水质排放指标作了明确规定,但对于污水处理过程中释放的气体污染物的类型及排放限值缺少详细说明.本文对城市污水处理厂不同污水处理工艺及不同污水处理单元在运行中所释放的气体污染物的特征进行了归纳总结,阐述了城市污水处理厂释放的主要恶臭挥发性有机物的产生途径、释放量及影响因素,并指出目前城市污水处理厂释放的气体污染物主要通过尾气末端收集综合处理的方式进行治理,而对于工艺运行参数与气体污染物释放特征之间的相关性关系仍需深入研究.     

大连湾挥发性有机污染物挥发速率常数估算

本文采用气－液双膜模型和大连湾水文参数，对大连湾检测出的挥发性有机物的挥发速率常数进行估算。结果表明，三氯乙烯等１４种挥发性有机物在大连湾海域中的挥发速率常数在８．０×１０＾－３ｈ－１－１．４×１０＾－２×＾－１之间，挥发半衰期在５０ｈ＝８０ｈ之间。因此，挥发至大气是这些在机物主要归宿。     

真菌降解挥发性有机污染物的特性与影响因素

介绍了利用真菌降解挥发性有机污染物的生物反应器的特性及发展状况。阐述了真菌反应器内填料的选择以及温度、湿度、pH、含氧量等条件对真菌活性的影响     

污泥自热式高温好氧消化技术研究进展

污泥自热式高温好氧消化(ATAD)具有反应速率快,停留时间短,病原微生物灭活效果好等优点,特别适合于小规模污水处理厂污泥的处理,在北美和欧洲已有较多的应用实例.系统总结了ATAD系统各方面的研究进展,包括AT-AD系统中微生物的种类与特性,ATAD污泥处理过程中微生物细胞、有机碳以及氮磷的转化规律,ATAD反应器运行控制参数,以及改善ATAD处理后污泥脱水性能的方法,并介绍了基于ATAD技术的新型污水及污泥处理工艺研究开发现状.     

车内空气中挥发性有机物的研究

采用热脱附-气相色谱/质谱联用法对4辆处于静止状态下的车辆内部空气中挥发性有机物(VOCs)进行了研究,共定性检出了48种有机物,其中C6~C9之间的组分较多;并对VOCs的总浓度进行了定量,1#~4#车分别为1846、2289、1104和3146μg/m3;其中BTEX占VOCs总量的20%~30%;车内VOCs浓度与温度及车辆使用年限密切相关。     

Comparison of the substrate effect on voc emissions from water based varnish and latex paint

BACKGROUND, AIMS AND SCOPE: The building materials are recognised to be major contributors to indoor air contamination by volatile organic compounds (VOCs). The improvement of the quality of the environment within buildings is a topic of increasing research and public interest. Legislation in preparation by the European Commission may induce, in the near future, European Union Member States to solicit the industries of paints, varnishes and flooring materials for taking measures, in order to reduce the VOC emissions resulting from the use of their products. Therefore, product characterisation and information about the influence of environmental parameters on the VOC emissions are fundamental for providing the basic scientific information required to allow architects, engineers, builders, and building owners to provide a healthy environment for building occupants. On the other hand, the producers of coating building materials require this information to introduce technological alterations, when necessary, in order to improve the ecological quality of their products, and to make them more competitive. Studies of VOC emissions from wet materials, like paints and varnishes, have usually been conducted after applying the material on inert substrates, due to its non-adsorption and non-porosity properties. However, in real indoor environments, these materials are applied on substrates of a different nature. One aim of this work was to study, for the first time, the VOC emissions from a latex paint applied on concrete. The influence of the substrate (uncoated cork parquet, eucalyptus parquet without finishing and pine parquet with finishing) on the emissions of VOC from a water-based varnish was also studied. For comparison purposes, polyester film (an inert substrate) was used for both wet materials. METHODS: The specific emission rates of the major VOCs were monitored for the first 72 h of material exposure in the atmosphere of a standardized test chamber. The air samples were collected on Tenax TA and analysed using thermal desorption online with gas chromatography provided with both mass selective detection and flame ionisation detection. A double exponential model was applied to the VOC concentrations as a function of time to facilitate the interpretation of the results. RESULTS AND DISCUSSION: The varnish, which was introduced in the test chamber 23 h after the application of the last layer of material, emitted mainly glycolethers. Only primary VOCs were emitted, but their concentrations varied markedly with the nature of the substrate. The higher VOC concentrations were observed for the parquets of cork and eucalyptus, which indicated that they have a much higher porosity and, therefore, a higher power of VOC adsorption than the finished pine parquet (and polyester film). The paint was introduced in the chamber just after its application. Only primary VOCs were emitted (esters, phthalates, glycolethers and white spirit) but some compounds, like 2-(2-butoxyethoxy)ethanol and diethylphthalate, were only observed for paint/polyester, which suggested that they were irreversibly adsorbed by the paint/concrete. Compared with the inert substrate, the rate of VOC emissions was lower for concrete in the wet-stage (first hours after the paint application) but slightly higher later (dry-stage) as a consequence of desorption. CONCLUSIONS: As to varnish, the substrates without finishing, like cork and eucalyptus parquets, displayed a higher power of adsorption of VOCs than the pine parquet with finishing, probably because they have a higher porosity. As concerns paint, the total masses of VOCs emitted were lower for concrete than for polyester, indicating that concrete reduces the global VOC emissions from the latex paint. Concrete is seen to have a strong power of adsorption of VOCs. Some compounds, namely 2-(2-butoxyethoxy)ethanol, diethylphthalate and TEXANOL (this partially), were either irreversibly adsorbed by the concrete or desorbed very slowly (at undetected levels). A similar behaviour had not been reported for gypsum board, a paint substrate studied before. RECOMMENDATIONS AND OUTLOOK: The present data suggest that concrete may be a recommendable substrate for paint in an indoor environment. As the nature of the substrate conditions the rate and nature of VOC emissions from wet materials, it must be explicit when emissions from composite materials are reported, in order to allow comparisons and labelling of the product in terms of indoor air quality.