‘Emulsion locks’ for the containment of hydrocarbons during surfactant flushing

Reversible double water in oil in water (W/O/W) emulsions were developed to contain subsurface hydrocarbon spills during their remediation using surfactant flushing. Double emulsions were prepared by emulsifying CaCl₂ solutions in canola oil, and subsequently by emulsifying the W/O emulsions in aqueous sodium alginate solutions. The formation of double emulsions was confirmed with confocal and optical microscopy. The double emulsions reversed and gelled when mixed with the surfactants sodium dodecyl sulfate (SDS) and cocamidopropyl betaine (CPB). Gels can act as ‘emulsion locks’ to prevent spreading of the hydrocarbon plume from the areas treated with surfactant flushing, as shown in sand column tests. Shear rheology was used to quantify the viscoelastic moduli increase (gelation) upon mixing the double emulsion with SDS and CPB. SDS was more effective than CPB in gelling the double emulsions. CPB and SDS could adsorb at the interface between water and model hydrocarbons (toluene and motor oil), lowering the interfacial tension and rigidifying the interface (as shown with a Langmuir trough). Bottle tests and optical microscopy showed that SDS and CPB produced W/O and O/W emulsions, with either toluene or motor oil and water. The emulsification of motor oil and toluene in water with SDS and CPB facilitated their flow through sand columns and their recovery. Toluene recovery from sand columns was quantitated using Gas-Chromatography Mass-Spectroscopy (GC-MS). The data show that SDS and CPB can be used both for surfactant flushing and to trigger the gelation of ‘emulsion locks’. Ethanol also gelled the emulsions at 100 mL/L.     

Polycyclic aromatic hydrocarbons in benthos of the northern Bering Sea Shelf and Chukchi Sea Shelf

Eighteen polycyclic aromatic hydrocarbons (PAHs) were detected in benthos collected onboard the ‘Snow Dragon’ in the Northern Bering Sea Shelf and Chukchi Sea Shelf during the 6^th Chinese National Arctic Research Expedition (CHINARE 2014). Σ₁₈PAHs for all biota samples ranged from 34.2 to 128.1 ng/g dry weight (dw), with the highest concentration observed in fish muscle (Boreogadus saida) samples close to St. Lawrence Island. The PAH composition pattern was dominated by the presence of lighter 3 ring (57%) and 2 ring (28%) PAHs, indicating oil-related or petrogenic sources as important origins of PAH contamination. Concentrations of alkyl-PAHs (1-methylnaphthalene and 2-methylnaphthalene) were lower than their parent PAH (naphthalene) in all biological tissue, and their percentage also decreased significantly (p<0.05) compared with those in the corresponding sediment. There were no significant relationships between PAH concentrations and trophic levels, which is possibly due to the combined results of the complex benthic foodweb in the subarctic/Arctic shelf region, as well as a low assimilation/effective metabolism for PAHs. According to toxic potency evaluation results from TCDD toxic equivalents (TEQs) and BaP-equivalent (BaPE) values, whelk (Neptunea heros) and starfish (Ctenodiscus crispatus) are two macroinvertebrate species showing relatively higher dioxin-like toxicity and carcinogenic risk.     

膜、柱串联固相萃取-高效液相色谱法测定水中多环芳烃(PAHs)的研究

建立了用膜-柱串联固相萃取(SPE)技术,甲醇和水作为流动相进行梯度洗脱,紫外和荧光检测器串联的高效液相色谱法(HPLC)分析水中EPA优先监控的16种PAHs的方法.     

固相萃取-气相色谱法测定水中硝基苯类有机污染物的方法研究

建立了固相萃取、毛细柱气相色谱-电子捕获检测器定量分析水中硝基苯类化合物的分析方法。通过对固相萃取柱的选择、固相萃取条件(样品溶液的pH值、上样速度、上样体积、洗脱液选择及配比)的优化,得出了最佳实验条件。穿透体积可达1.5L,回收率在80%~105%,最小检出浓度在0.00037~0.072μg/L之间,均大大低于GB13194-91的规定。相对标准偏差在0.7%~5.3%之间。该方法准确、简单,重现性好、回收率高,污染小。     

济南市环境空气中多环芳烃的来源识别和解析

根据环境空气污染源标识物的确定和多环芳烃降解行为,利用CMB受体模型进行拟合计算,确定多环芳烃污染源贡献率,并在比较多环芳烃实测值和CMB受体模型计算值的基础上,得出可吸入颗粒物中多环芳烃源解析结果,确定机动车污染源是济南市可吸入颗粒物中多环芳烃的主要贡献源。     

梯度淋洗快速分析水中多环芳香烃

根据流动相极性理论，采用梯度淋洗一检测器编程方法检测多环芳烃，大大缩短了分析时间，并提高了灵敏度和精密度．为进一步定量分析提供了优良的途径。     

多环芳烃的几种理化参数与LC_(50)的相关性研究

对多环芳烃(PAHS)4种理化参数(K;W、Sw。X Vv。)与 LCO的相关关系进行了研究,建立了 4种一元线性回归方程。结果表明,4种参数的相关系数分别为:0.刀66、08083、09488、0.9570,经r检验,后两种属高度显著相关.用所建立的一元线性回归方程对7种PAHS的LC。进行估算,估算值与实测值相比,平均相对误差分别为58.84％、32.23％、1761％、198％,用l和V＊.H对LClj进行估算的估算精度也较高。经比较,提出用(。估算P＊比对麦穗鱼＊CO的新方法。     

表面活性剂和多环芳烃的复合生态效应研究进展

简要论述了表面活性剂和多环芳烃在环境中的各自行为，包括表面活性剂的定义，分类和对难溶有机化合物的增溶作用机理，多环芳烃的产生途径和分布，表面活性剂和多环芳烃的危害及生物去除方式等，在此基础上着重探讨表面活性剂对多环芳烃生物去除的影响作用机理，阐述了影响表面活性剂和多环芳烃复合生态效应的各种因素及最新研究进展。对该领域需进一步研究的问题进行了展望。     

重庆大气可吸入颗粒物中多环芳烃的分析测定

本文报告了重庆大气可吸入颗粒物(IP)中多环芳烃(PAH)的分析测定方法和结果.用GC-MS定性和定量分析了重庆IP中的PAH;研究了IP中PAH的种类和分布情况;确认重庆IP中存在甲基多环芳烃(MePAH)、约占33%;颗粒大小分布表明,约有98%PAH存在于小于3μm的颗粒中.     

Characterisation of polycyclic aromatic hydrocarbons in flue gas and residues of a full scale fluidized bed combustor combusting non-hazardous industrial waste

This paper studies the fate of PAHs in full scale incinerators by analysing the concentration of the 16 EPA-PAHs in both the input waste and all the outputs of a full scale Fluidized Bed Combustor (FBC). Of the analysed waste inputs i.e. Waste Water Treatment (WWT) sludge, Refuse Derived Fuel (RDF) and Automotive Shredder Residue (ASR), RDF and ASR were the main PAH sources, with phenanthrene, fluoranthene and pyrene being the most important PAHs. In the flue gas sampled at the stack, naphthalene was the only predominant PAH, indicating that the PAHs in FBC’s combustion gas were newly formed and did not remain from the input waste. Of the other outputs, the boiler and fly ash contained no detectable levels of PAHs, whereas the flue gas cleaning residue contained only low concentrations of naphthalene, probably adsorbed from the flue gas. The PAH fingerprint of the bottom ash corresponded rather well to the PAH fingerprint of the RDF and ASR, indicating that the PAHs in this output, in contrast to the other outputs, were mainly remainders from the PAHs in the waste inputs. A PAH mass balance showed that the total PAH input/output ratio of the FBC ranged from about 100 to about 2600 depending on the waste input composition and the obtained combustion conditions. In all cases, the FBC was clearly a net PAH sink.