The Interaction of Vapour Phase Organic Compounds with Indoor Sinks

The interaction of indoor air pollutants with interior surfaces (i.e., sinks) is a well known, but poorly understood, phenomenon. Studies have shown that re-emissions of adsorbed organic vapours can contribute to elevated concentrations of organics in indoor environments. Research is being conducted in small environmental test chambers to develop data for predicting sink behaviour. This paper reports on the development of sink models based on fundamental mass transfer theory. The results of experiments conducted to determine the magnitude and rate of adsorption and desorption of vapour phase organic compounds for several materials are presented. Five materials were evaluated: carpet, painted wallboard, ceiling tile, window glass, and upholstery. Two organic compounds were tested with each material: tetrachloroethylene (a common cleaning solvent) and ethylbenzene (a common constituent of petroleum-based solvents widely used in consumer products). The results of the experimental work are presented showing the relevant sink effect parameters for each material tested and comparing the sorptive behaviour of the two organic compounds evaluated. An indoor air quality (IAQ) model was modified to incorporate adsorption and desorption sink rates. The model was used to predict the temporal history of the concentration of total vapour phase organics in a test house after application of a wood finishing product. The predicted results are presented and compared to measured values. Suggestions for further research on indoor sinks are presented.     

Aqueous photodegradation of fenthion by ultraviolet B irradiation: contribution of singlet oxygen in photodegradation and photochemical hydrolysis

The objective of this study was to evaluate the photodegradation of the organophosphorus pesticide fenthion in the environment from a human health effect viewpoint. The major photodegradation products of fenthion in an aqueous solution under UVB irradiation (280-320nm radiation) were identified as fenthion sulfoxide, 3-methyl-4-methylthiophenol (MMTP), dimethyl phosphorothioate and 3-methyl-4-methylsulfinylphenol (MMSP). MMTP, dimethyl phosphorothioate and MMSP were discovered as novel photodegradation products of fenthion. Kinetic analysis of these products showed the formation of MMTP and dimethyl phosphorothioate by the photochemical hydrolysis of fenthion, which was accelerated under alkaline conditions. The former was further oxidized to MMSP. Fenthion sulfoxide was directly produced by the oxidative reaction of fenthion. Contribution of dissolved oxygen in this photooxidation was observed by replacing the air with nitrogen gas in the reaction system, which prevented oxidative formation of fenthion sulfoxide from fenthion and MMSP from MMTP. These oxidative compounds were also formed from fenthion in the presence of singlet oxygen (1O2) generated by the visible light irradiation of rose bengal solution, while 1O2 scavengers, L-histidine and sodium azide (NaN3) inhibited this reaction. The aqueous photolysis mechanisms of fenthion were proposed from a kinetic photolysis experiment study as follows: there were two kinds of UVB photodegradation pathways of fenthion, one being photochemical hydrolysis of the phosphorus-O-phenyl ester to form MMTP and dimethyl phosphorothioate, and the other oxygenation triggered by 1O2 and producing fenthion sulfoxide and MMSP. Therefore, the steady photodegradation products of fenthion in the water environment may be fenthion sulfoxide and MMSP.     

Environmental aspects of VOCs evolved in the early stages of human decomposition

In the present study, the time profile, measured as "accumulation", of volatile organic compounds (VOCs) produced during the early stages of human decomposition was investigated. A human cadaver was placed in a sealed bag at approximately the 4th day after death. Evolved VOCs were monitored for 24 h by sampling at different time intervals. VOCs produced were analyzed by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). Over 30 substances were identified in total. These included mainly aliphatic and aromatic hydrocarbons, oxygenated compounds (alcohols, aldehydes, ketones) and organic sulfides. The last were the most prominent class of compounds identified. Eleven compounds were present in all the sampling cycles and constitute a "common core": ethanol, 2-propanone, dimethyl disulfide, methyl benzene, octane, 2-butanone, methyl ethyl disulfide, dimethyl trisulfide and o-, m- and p-xylenes. The last sampling cycle yielded the most abundant compounds in number and quantities. Inorganic gases such as CO2, CO, NH3 and H2S were also determined. The fundamental physicochemical properties of the evolved VOCs were used for evaluating their environmental impacts. It appears that the decay process, which is a dynamic procedure, can provide chemical signals that might be detected and properly evaluated by experts in the fields of forensic sciences, search and rescue units and environmental scientists.     

Experimental studies on the performance,emission and combustion characteristics of a biodiesel-fuelled (Pongamia methyl ester) diesel engine with diethyl ether as an oxygenated fuel additive

This paper investigates the combustion, performance and emission characteristics of a single-cylinder diesel engine using neat biodiesel (Pongamia methyl ester) with two different blends (10% and 15% diethyl ether [DEE]) at different load conditions. The measured values of brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), exhaust gas temperature (EGT), carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO) and smoke were calculated and analysed and compared with diesel fuel. The results showed that a significant reduction in NO and smoke emissions for neat biodiesel with 15% DEE blend compared with neat biodiesel at full load conditions. The peak pressure and heat release rate were decreased, and maximum rate of pressure rise and ignition delay were also decreased with DEE blends at full load. On the whole, it is concluded that the biodiesel with 15% DEE blend showed better results with respect to efficiency and emissions point of view compared with biodiesel.     

Identification of organic compounds and ecotoxicological assessment of sewage treatment plants (STP) effluents

An integrated approach combining chemistry and biological methods was conducted to assess the toxicity of seven sewage treatment plant effluents. Solid phase concentration procedures were applied to facilitate the study of organic micro pollutants. A chemical analysis was performed by GC/MS. Organic fraction toxicity was determined by using bioassays such as Daphnia magna and Chlorella vulgaris tests and sub-lethal effects were also evaluated by using Salmonella typhimurium Test (mutagenicity), recombinant yeast screen (estrogenicity), and Oryzias latipes embryo-larval test. More than 49 compounds were detected in the organic fraction due to the various inputs of each effluents. The most frequently detected compounds in the effluents were bisphenol A (BPA), octylphenol (OP), 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (DEHP) and 1,2-benzenedicarboxylic acid, bis(methylpropyl) ester (DBP). Biological assays showed toxicity effects on D. magna tests in all samples, whereas toxicity on C. vulgaris or S. typhimurium tests were not observed. Estrogenicity and teratogenicity were observed in several samples. The cause-effect relationship could not be established given the high chemical complexity of the effluents and the lack of information available on 70% of the detected compounds subsequent to reviewing various data bases. Nevertheless, due to the high chemical variability revealed by STP effluents, bioassay sets may provide a very useful amount of information for detecting potential toxicity risks.     

Experimental investigation of engine emissions with marine gas oil-oxygenate blends

This paper investigates the diesel engine performance and exhaust emissions with marine gas oil-alternative fuel additive. Marine gas oil (MGO) was selected as base fuel for the engine experiments. An oxygenate, diethylene glycol dimethyl ether (DGM), and a biodiesel (BD) jatropha oil methyl ester (JOME) with a volume of 10% were blended with the MGO fuel. JOME was derived from inedible jatropha oil. Lower emissions with diesel-BD blends (soybean methyl ester, rapeseed methyl ester etc.) have been established so far, but the effect of MGO-BD (JOME) blends on engine performance and emissions has been a growing interest as JOME (BD) is derived from inedible oil and MGO is frequently used in maritime transports. No phase separation between MGO-DGM and MGO-JOME blends was found. The neat MGO, MGO-DGM and MGO-JOME blends are termed as MGO, Ox10 and B10 respectively. The experiments were conducted with a six-cylinder, four-stroke, turbocharged, direct-injection Scania DC 1102 (DI) diesel engine. The experimental results showed significant reductions in fine particle number and mass emissions, PM and smoke emissions with Ox10 and B10 fuels compared to the MGO fuel. Other emissions including total unburned hydrocarbon (THC), carbon monoxide (CO) and engine noise were also reduced with the Ox10 and B10 fuels, while maintaining similar brake specific fuel consumption (BSFC) and thermal efficiency with MGO fuel. Oxides of nitrogen (NOx) emissions, on the other hand, were slightly higher with the Ox10 and B10 fuels at high engine load conditions.     

EU-wide monitoring survey on emerging polar organic contaminants in wastewater treatment plant effluents

In the year 2010, effluents from 90 European wastewater treatment plants (WWTPs) were analyzed for 156 polar organic chemical contaminants. The analyses were complemented by effect-based monitoring approaches aiming at estrogenicity and dioxin-like toxicity analyzed by in vitro reporter gene bioassays, and yeast and diatom culture acute toxicity optical bioassays. Analyses of organic substances were performed by solid-phase extraction (SPE) or liquid–liquid extraction (LLE) followed by liquid chromatography tandem mass spectrometry (LC-MS-MS) or gas chromatography high-resolution mass spectrometry (GC-HRMS). Target microcontaminants were pharmaceuticals and personal care products (PPCPs), veterinary (antibiotic) drugs, perfluoroalkyl substances (PFASs), organophosphate ester flame retardants, pesticides (and some metabolites), industrial chemicals such as benzotriazoles (corrosion inhibitors), iodinated x-ray contrast agents, and gadolinium magnetic resonance imaging agents; in addition biological endpoints were measured. The obtained results show the presence of 125 substances (80% of the target compounds) in European wastewater effluents, in concentrations ranging from low nanograms to milligrams per liter. These results allow for an estimation to be made of a European median level for the chemicals investigated in WWTP effluents. The most relevant compounds in the effluent waters with the highest median concentration levels were the artificial sweeteners acesulfame and sucralose, benzotriazoles (corrosion inhibitors), several organophosphate ester flame retardants and plasticizers (e.g. tris(2-chloroisopropyl)phosphate; TCPP), pharmaceutical compounds such as carbamazepine, tramadol, telmisartan, venlafaxine, irbesartan, fluconazole, oxazepam, fexofenadine, diclofenac, citalopram, codeine, bisoprolol, eprosartan, the antibiotics trimethoprim, ciprofloxacine, sulfamethoxazole, and clindamycine, the insect repellent N,N′-diethyltoluamide (DEET), the pesticides MCPA and mecoprop, perfluoroalkyl substances (such as PFOS and PFOA), caffeine, and gadolinium.     

高强度水溶性环氧灌浆材料的制备

在衣康酸环氧酯树脂的制备过程中引入了活性助溶剂,制备了低黏度的水溶性灌浆材料;研究了含水量、引发剂、促进剂、交联剂、共聚组分、缓凝剂、硅烷偶联剂对衣康酸环氧酯树脂水溶性灌浆材料性能的影响.通过优选各种组分的最佳配比,得到了综合性能更加优异的环保型水溶性环氧灌浆材料.     

Identification and determination of trace organic substances in tap water by computerized gas chromatography-mass spectrometry and mass fragmentography

Tap water was examined for the presence of trace organic substances by using the Amberlite XAD-2 resin adsorption method, computerized gas chromatography-mass spectrometry, high resolution mass spectrometry, and mass fragmentography. Chemical ionization and field desorption mass spectrometry were used for the analysis of high polar compounds. By these methods, a large number of alkylbenzenes, odorous components (menthol, acetophenone and its derivatives, and benzaldehyde), and several plasticizers (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di(2-ethylhexyl) phthalate, di(2-ethylhexyl) adiptate, and tributyl phosphate) were found in a concentration of 1–240 parts per thousand million.     

Analysis of nitroaromatics in aqueous samples by capillary supercritical fluid chromatography

The extraction and analysis of nitroaromatics from aqueous environmental samples was examined. Two extraction methods; liquid‐liquid extraction with dichloromethane as extracting solvent and solid phase extraction with C₁₈ cartridge were carried out to determine the selectivity and extraction efficiencies of each method. In this investigation, eight nitroaromatics were selected as the test compounds. The extracts were then analysed using capillary supercritical fluid chromatography with flame ionization detection and with carbon dioxide as mobile phase. Satisfactory separation of the eight nitroaromatics including three pairs of isomers could be achieved. Detection limits in the range of 5 to 40 ppm were obtained using this system. Higher extraction efficiencies were obtained using the liquid‐liquid extraction method compared to the solid phase extraction method.     

Treatment of MTBE by air stripping, carbon adsorption, and advanced oxidation: technical and economic comparison for five groundwaters

An investigation was made of the treatability of methyl tert-butyl ether (MTBE) in five groundwaters with highly varied water quality characteristics. Air stripping, granular activated carbon (GAC) adsorption, and the O(3)/H(2)O(2) and UV/H(2)O(2) advanced oxidation processes were compared in a mobile water treatment pilot plant under a variety of process conditions. Air stripping was shown to have the lower unit treatment costs for higher flowrates (i.e., 3800L/min), although relatively tall towers were required for greater treatment requirements. At low flowrates (i.e., 38L/min), advanced oxidation provided the lowest treatment costs for four of five waters (but was ineffective for a high chemical oxygen demand water). Both the O(3)/H(2)O(2) and UV/H(2)O(2) processes were more efficient at pH 7 versus 9 due in part to increased scavenging at higher pH. GAC was examined using rapid small-scale column tests (RSSCT). GAC was effective at most conditions, although it was also the most costly alternative for most waters. The results of this study can help to provide specific guidance into process selection for treating MTBE in contaminated groundwaters.     

Application of a novel reference material in an international round robin test on material emissions testing

Emission testing of products is currently a rapidly increasing field of measurement activity. Labeling procedures for construction products are based on such emission test chamber measurements, and hence, measurement performance should be verified. One possible route is to conduct testing of one material in different laboratories within a round robin test (RRT), ideally using homogeneous reference materials, which can be used within interlaboratory studies or as part of the quality management system to ensure comparable results. The applicability of a lacquer system with nine added VOCs (hexanal, styrene, n‐decane, limonene, 2‐ethyl‐1‐hexanol, N‐methyl‐α‐pyrrolidone, 2‐ethylhexyl acrylate, dimethyl phthalate, and n‐hexadecane) was evaluated in an international RRT with 55 participating laboratories. An intralaboratory quality check confirmed the homogeneity and reproducibility of the lacquer material for most of the compounds (RSD 5%‐6%), which was confirmed in the RRT. However, emissions varied for the polar compound N‐methyl‐α‐pyrrolidone and the higher boiling compounds 1,2‐dimethyl phthalate, and n‐hexadecane which could be traced back to analytical issues. In the RRT, the interlaboratory relative standard deviations (RSDs) ranged from 30% to 65% for all participants but for reference laboratories the range was between 20% and 45%.     

Evaluation of a teflon helix liquid-liquid extractor for concentration of trace organics from water into methylene chloride

A continuous liquid-liquid extraction system (CLLE) for concentrating trace organics from water into methylene chloride for analysis was designed, built and evaluated. The CLLE uses Teflon coils for phase contact and gravity phase separation. The system includes a self-contained excess solvent distillation chamber, so the methylene chloride is recovered and recycled.A 901. Milli-Q water blank was run on the system. The CLLE extract was concentrated to 4 ml by Kuderna-Danish distillation, giving a 22,500:1 concentration ratio.Aqueous mixtures of organic compounds were used as test probes to evaluate the CLLE. Recovery values were determined for these compounds using CLLE and batch LLE (separatory funnel liquid-liquid extraction), and CLLE recoveries were found to be similar to those of batch LLE. Several statistical methods were applied to the data. For 9 of the 12 compounds that could be evaluated statistically, recoveries of 1 and 12.51. aqueous samples extracted by CLLE were found to be equivalent to l liter batch LLE recovery values.The units are portable, and are currently in service sampling raw and treated water at locations in the northeastern United States.     

Extraction of Lead from Water Using Homogeneous Liquid–Liquid Microextraction via Flotation Assistance Method and UV-Vis Spectrophotometric Determination

Homogeneous liquid-liquid microextraction via flotation assistance method was developed for extraction of lead in water. A mixture of extraction solvent (1-decanol) and disperser solvent (acetone) containing dithizone as chelating agent is injected into microextraction cell. Then an aqueous sample is injected into microextraction cell until the mixture of solvent forms initial state a homogeneous solution and then forms an emulsion consisting of fine droplets of the extraction solvent, disperser solvent and water. Using air flotation, the extraction solvent is transferred to the surface of the mixture and is collected by means of a micro-syringe. Then 25 μL of the collected organic solvent is diluted with 800 μL decanol and is analyzed with spectrophotometer in 520 nm wavelength. Also, the thermochemistry of complexation reactions was investigated at PM6 and B3LYP/6-31G* computational level.     

Effect of organic solvents on growth of freshwater algae

The impact of acetone, methanol, ethanol and dimethyl sulfoxide (DMSO) as carrier solvents on two species of algae was investigated. Scenedesmus quadricauda of green algae and Anabaena flos‐aquae of blue green algae were subjected to different concentrations of the studied solvents which ranged from 0.01 to 7.29 mL/L for 10 days in batch studies. The data recommended the use of acetone, ethanol and methanol than dimethyl sulfoxide in this order as a carrier solvent for chemical toxicity tests using a maximum concentration of 7.29 mL/L which represents 0.729% (volume/volume) in the algal bioassay test.     

酰胺型聚羧酸减水剂合成工艺及性能研究

酯化反应下,甲基丙烯、聚乙二醇单甲醚等单体可形成酯化大单体,与甲基丙烯酸进一步聚合可得到聚羧酸系减水剂。该过程不仅合成工艺较复杂,而且原材料成本较高,难以体现出很大的优势。本文主要探讨酰胺型聚羧酸减水剂合成工艺,采用聚醚胺、聚丙烯酸为共聚单体,通过聚合直接得到减水剂。采用最佳工艺合成的产品相对于其他一甲基丙烯酸和聚乙二醇单甲醚为单体合成的产品相比,前者性能明显更高,在有着很高坍落度保持性要求的混凝土中十分适用。     

A comparative study of performance and combustion characteristics of a CI diesel engine fuelled with B20 biodiesel blends

This paper aims to study the diesel engine performance and combustion characteristics fuelled with Banalities aegyptiaca oil methyl ester, palm oil methyl ester, sesame methyl ester oil, rapeseed methyl ester oil, soybean oil methyl ester and diesel fuel. In this present work, only 20% of each biodiesel blends was tested in diesel engine; stated that the possible use of biodiesel of up to 20% in a diesel engine without modification in literature. A single-cylinder, auxiliary water-cooled and computer-based variable compression ratio diesel engine was used to evaluate their performance at constant speed and at measured load conditions. The performance and combustion tests are conducted using each of the above test fuels, at a constant speed of 5000?rpm. Thus, the varying physical and chemical properties of test fuels against pure diesel are optimised for better engine performance.

Abbreviations: BP: brake power; BSFC: brake-specific fuel consumption; BTE: brake thermal efficiency; CO: carbon monoxide; CP: cylinder pressure; DP: diesel pressure; EGT: exhaust gas temperature; HC: hydrocarbon; HRR: heat release rate; NO _x : nitric oxides; PM: particulate matter; TDC: top dead centre; VCR: variable compression ratio     

Biochemical studies of some hydrolytic enzymes in malathion treated germinating seeds of Vigna sinensis (l): effect of growth hormone supplementation

Studies have been carried out on the different hydrolytic enzymes of the germinating seeds of V. sinensis (L) by exposing them to various concentrations of malathion (O, O dimethyl phosphorodithioate of diethyl mercaptosuccinate), an organophosphorus insecticide. At 50 ppm the insecticide induces the seedling growth and at 400 ppm caused a significant inhibition. On simultaneous application of either of the plant hormones, i.e., IAA, GA₃ and kinetin with different concentrations of malathion, it was found that there was a trend to overcome of malathion inhibition of seedling growth. It was also found that treatment of seeds with growth hormones, at 400 ppm malathion exposure, helps to restore the normal activities of certain hydrolytic enzymes, which showed otherwise, significant altered activities. Kinetic studies show that the stimulation of acid phosphatase activity due to malathion exposure was non‐competitive in nature.     

Toxicological assessment of indium nitrate on aquatic organisms and investigation of the effects on the PLHC-1 fish cell line

Indium nitrate is mainly used as a semiconductor in batteries, for plating and other chemical and medical applications. There is a lack of available information about the adverse effects of indium compounds on aquatic organisms. Therefore, the toxic effects on systems from four trophic levels of the aquatic ecosystem were investigated. Firstly, the bacterium Vibrio fischeri, the alga Chlorella vulgaris and the cladoceran Daphnia magna were used in the toxicological evaluation of indium nitrate. The most sensitive model was V. fischeri, with a NOAEL of 0.02 and an EC(50) of 0.04 mM at 15 min. Although indium nitrate should be classified as harmful to aquatic organisms, it is not expected to represent acute risk to the aquatic biota. Secondly, PLHC-1 fish cell line was employed to investigate the effects and mechanisms of toxicity. Although protein content, neutral red uptake, methylthiazol metabolization, lysosomal function and acetylcholinesterase activity were reduced in cells, stimulations were observed for metallothionein levels and succinate dehydrogenase and glucose-6-phosphate dehydrogenase activities. No changes were observed in ethoxyresorufin-O-deethylase activity. To clarify the main events in PLHC-1 cell death induced by indium nitrate, nine modulators were applied. They were related to oxidative stress (alpha-tocopherol succinate, mannitol and sodium benzoate), disruption of calcium homeostasis (BAPTA-AM and EGTA), thiol protection (1,4-dithiotreitol), iron chelation (deferoxiamine) or regulation of glutathione levels (2-oxothiazolidine-4-carboxylic acid and malic acid diethyl ester). The main morphological alterations were hydropic degeneration and loss of cells. At least, in partly, toxicity seems to be mediated by oxidative stress, and particularly by NADPH-dependent lipid peroxidation.     

An evaluation of solid phase microextraction for analysis of odorant emissions from stored biosolids cake

Odors are a common occurrence at wastewater treatment plants, biosolids processing facilities and biosolids recycling locations. Accurate, objective measurement techniques are needed to monitor emissions, to develop new waste handling procedures and to reduce the production of the volatile gases. The objective of this study was to evaluate the use of solid phase microextraction for measuring common odorants that are found in biosolids facilities. The odorants were collected and concentrated by solid phase microextraction (SPME) and then quantified by gas chromatography with detection by mass spectrometry. A 75-microm Carboxen-Polydimethylsiloxane coating was used for the analysis of trimethylamine, dimethyl sulfide, dimethyl disulfide and methyl mercaptan. Gaseous standards were generated for individual compounds and for dry and wet mixture from permeation apparatus. The differences in sensitivity between fibers, the competition between analytes and water vapor for the active sites on the fiber and the lack of production of artifacts make SPME suited for qualitative analysis and enables quick screening for the identification of compounds with adverse organoleptic characteristics.