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731.
ABSTRACT: A sample transfer device was designed to provide a closed loop sampling system between a ground water sampling pump and a 40 ml volatile organic compound (VOC) vial. The same attachment can also be used with a bailer. The unit is constructed of a poly-tetrafluoroethylene (PTFE) body into which two stainless steel needles are press fitted. The needles puncture the Teflon septum of a vial; fluid flows through the longer needle into the vial and exits the vial from the shorter needle. The device eliminates sample transfer bias associated with head space, visible gas bubbles, and atmospheric contamination. Field sampling designed to determine differences in trichloroethylene (TCE) concentrations presumedly due to the device were statistically significant in one case, and insignificant in the second.  相似文献   
732.
测定了酚类化合物对硝化颗粒污泥活性抑制的logIC50值,以量子化学参数为自变量,应用偏最小二乘法(PLS),建立了酚类化合物对硝化颗粒污泥活性抑制的定量结构-活性相关(QSAR)模型。模型所提取的PLS主成分所能解释的因变量总方差的比例Qc2um为0.820,表明模型具有较好的稳定性和预测能力。模型的结果表明,影响酚类化合物对硝化颗粒污泥活性抑制的主要因素是logkow、CCR和Ehomo,酚类化合物对硝化颗粒污泥活性抑制的logIC50随着分子logkow的增大而减小,随着Ehomo和CCR的增大而增大。  相似文献   
733.
对固体废物中挥发性有机物浸出方法的几点实验探讨   总被引:1,自引:1,他引:0  
采用零顶空提取器,对陈旧油墨渣和蒽琨渣样品中的挥发性有机物进行了浸出实验和分析测定,浸出液采用静态顶空分流进样、GC/MS法分析。对影响挥发性有机物浸出效率的因素进行了研究,结果表明,浸提剂加入方式、浸出时间和浸出液收集方法等对分析结果准确度有较大影响。  相似文献   
734.
通过大量实验,研究建立了水体中9种酚类化合物同时测定的多个监测分析方法,包括液液萃取-气相色谱-氢火焰检测器法、液液萃取-气相色谱-质谱法、液液萃取-衍生化气相色谱-质谱法、固相萃取-液相色谱-紫外检测器法和固相微萃取-气相色谱-质谱法。研究表明各个分析方法均具有较高的灵敏度,方法检出限在0.03~2.5 μg/L之间,能满足相关环境工作的需要。经方法适用性和可操作性比较,推荐选择固相微萃取-气相色谱-质谱法用于应急水样的快速测定、固相萃取-液相色谱-紫外检测器法用于地表水等清洁水样的测定、液液萃取-气相色谱-氢火焰检测器法用于工业废水等污染水样的测定。  相似文献   
735.
p(4-vinylpyridine) (p(4-VP)) hydrogels were prepared in bulk (macro, 5 × 6 mm) and in nanosizes (370 nm) dimensions. The prepared hydrogels were used to remove organic aromatic contaminates such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), phenol (Ph) and nitrobenzene (NB) from an aqueous environment. Important parameters affecting the absorption phenomena, such as the initial concentration of the organic species and the absorbent, absorption rate, absorption capacity, pH and the temperature of the medium, were evaluated for both hydrogel sizes. The absorption capacity of bulk and microgels were found to be 4-NP > 2-NP > Ph > NB. Furthermore, p(4-VP) microgels were embedded in poly(acrylamide) (p(AAm)) bulk hydrogel as a microgel-hydrogel interpenetrating polymer network and proved to be very practical in overcoming the difficulty of using the microgels in real applications. Moreover, it was demonstrated that separately prepared magnetic ferrite particles inserted inside p(4-VP) microgels during synthesis allowed for trouble-free removal of p(4-VP)-magnetic composite microgels from the aqueous environment by an externally applied magnetic field upon completion of their task.  相似文献   
736.
异(臭)味气体对人体的危害非常严重,尤其是有机化工企业在生产过程中排放的尾气会对周围环境造成严重污染。本文简要介绍了在实验室条件下低温等离子体对异(臭)味气体分子的分解作用及其在工业上的应用实例。  相似文献   
737.
浠ュ箍瑗垮钩鏋滃幙榫欎綍鐢熸€侀噸寤虹ず鑼冨尯鐨勭煶婕犲寲灞卞湴澶嶅悎鐢熸€佺郴缁熶负渚?渚濇嵁璇曢獙鐮旂┒鍙婁笓瀹跺挩璇㈢殑缁撴灉,鏋勫缓浜嗕竴涓熀浜庤嚜鐒跺瓙绯荤粺銆佺ぞ浼氬瓙绯荤粺銆佺粡娴庡瓙绯荤粺鐨勮瘎浠锋寚鏍囦綋绯?閲囩敤灞傛鍒嗘瀽娉曞鎸囨爣浣撶郴涓悇鎸囨爣鐨勬潈閲嶅€艰繘琛屼簡鍒嗘瀽,搴旂敤鎸囨暟璇勪环妯″瀷瀵圭煶婕犲寲灞卞湴澶嶅悎鐢熸€佺郴缁熻繘琛岀患鍚堣瘎浼?灞傛鍒嗘瀽缁撴灉琛ㄦ槑,妞嶈瑕嗙洊鐜囥€佷汉绫绘椿鍔ㄥ己搴︺€佺墿绉嶅鏍锋€с€佺墿璐ㄧ敓娲绘寚鏁般€佺煶婕犲寲绋嬪害銆佹按鍦熸祦澶辩▼搴︾瓑鎸囨爣鐨勬潈閲嶅€艰緝澶?鏄煶婕犲寲灞卞湴澶嶅悎鐢熸€佺郴缁熺殑閲嶈褰卞搷鍥犲瓙;鎸囨暟璇勪环妯″瀷鐨勮瘎浠风粨鏋滆〃鏄?鐭虫紶鍖栧北鍦板鍚堢敓鎬佺郴缁熺殑鎬讳綋璐ㄩ噺杈冨樊,浣嗛€氳繃鐢熸€佺ず鑼冨尯寤鸿,鏀瑰杽澶嶅悎鐢熸€佺郴缁熶腑鐨勬琚姸鍐?鏀瑰杽鍐滀笟鐢熶骇鏉′欢鍜屾帹骞垮厛杩涘啘涓氭妧鏈?鎻愰珮绯荤粺涓汉绫荤殑鐢熸椿姘村钩,鍙互浣垮鍚堢敓鎬佺郴缁熶腑绀句細銆佺粡娴庛€佺幆澧?涓瓙绯荤粺鐨勮浆杩愬姛鑳介€愭笎瓒嬩簬鍗忚皟,鎬讳綋璐ㄩ噺閫愭笎濂借浆.  相似文献   
738.
Cd、Zn、Pb单因素及复合污染对土壤酶活性的影响   总被引:6,自引:0,他引:6  
通过Cd、Zn、Pb单因素处理和复合因素处理的对比性研究发现,无论是单因素或复因素对土壤酶活性的抑制效应顺序均为 Cd> Zn> Pb;在所研究的 4种土壤酶中,脲酶受重金属的抑制作用最为敏感; Cd、 Zn、 Pb复合污染与各单因素的影响有较大差异,同时,Cd、Zn、Pb复合污染对4种土壤酶活性的影响效应亦不同。其复合污染对脲酶表现出协同抑制负效应的特征;对过氧化氢表现出一定的屏蔽作用或拮抗作用;转化酶和碱性磷酸酶主要因Cd浓度的变化而变化。  相似文献   
739.
To better understand the atmospheric behaviour of pesticides, heterogeneous ozonolysis of three herbicides (alachlor, terbuthylazine and trifluralin) adsorbed on silica particles were performed in a flow reactor. The experimental setup used in this study and previously validated (Pflieger et al., 2009) has been specially developed to investigate extremely slow reactivity. The pesticides were adsorbed on particles using a gas/solid adsorption equilibrium, in order to simulate atmospheric conditions. After exposure to ozone concentrations ranging from 5 to 41 ppm during 90 min to 6 h, the kinetics were calculated by comparing the initial and the remaining amounts of pesticides adsorbed on silica particles. This work offers the first results of heterogeneous ozonolysis of alachlor and trifluralin adsorbed on mineral particles. Although alachlor and terbuthylazine were expected to react with ozone, no degradation was observed which leads to a lifetime higher than 8 months towards ozonolysis (for 40 ppb of O3). A significant degradation of trifluralin adsorbed on silica particles by heterogeneous ozonolysis was observed. The experimental data could be fit by both the Langmuir–Rideal and the Langmuir–Hinshelwood models resulting in atmospheric lifetimes (towards heterogeneous ozonolysis) of 40 and 32 days respectively (for 40 ppb of O3). These results are discussed and compared to other studies.  相似文献   
740.
This study assessed volatile organic compound (VOC) emission characteristics from wastewater treatment plants (WWTPs) in five Taiwanese industrial districts engaged in numerous manufacturing processes, including petrochemical, science-based industry (primarily semiconductors, photo-electronics, electronic products and biological technology), as well as multiple manufacturing processes (primarily pharmaceuticals and paint manufacturing). The most aqueous hydrocarbons dissolved in the wastewater of Taiwanese WWTPs were acetone, acrylonitrile, methylene chloride, and chloroform for the petrochemical districts; acetone, chloroform, and toluene for the science-based districts; and chlorinated and aromatic hydrocarbons for the multiple industrial districts. The aqueous pollutants in the united WWTPs were closely related to the characteristics of the manufacturing plants in the districts. To effectively prevent VOC emissions from the primary treatment section of petrochemical WWTPs, the updated regulations governing VOC emissions were issued by the Taiwanese Environmental Protection Administration in September 2005, legally mandating a seal cover system incorporating venting and air purification equipment. Cost analysis indicates that incinerators with regenerative heat recovery are optimal for treating high VOC concentrations, exceeding 10,000ppm as CH(4), from the oil separation basins. However, the emission concentrations, ranging from 100 to 1000ppm as CH(4) from the other primary treatment facilities and bio-treatment stages, should be collected and then injected into the biological oxidation basins via existing or new blowers. The additional capital and operating costs required to treat the VOC emissions of 1000ppm as CH(4) from primary treatment facilities are less than US$0.1 for perm(3) wastewater treatment capacity.  相似文献   
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