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Methyl tert -butyl ether (MTBE), as a widely used gasoline additive, is suspected of being environmentally toxic. MTBE accumulates mainly in adipose tissue, but its effect on obesity or obesity-related metabolic disorders has not been well understood yet. Therefore, we examined the effect of MTBE on the adipose function and the related metabolic processes with both 3T3-L1 cell line and C57BL/6J mice model. We found that exposure to MTBE at the environmental relevant concentration (100 μmol/L) could significantly induce differentiation of preadipocyte and disturb insulin-stimulated glucose uptake of mature adipocyte. The in vivo observation in male mice showed a positive correlation of visceral white adipose tissue (vWAT) expansion and cell size increase with MTBE treatment in 14 weeks. Glucose tolerance and insulin sensitivity tests demonstrated that MTBE at 1000 μg/(kg·day) disturbed the systemic glucose metabolism in a gender-specific manner, which might be partly attributed to the alterations of gut microbiota community at genus level with respect to Akkermansia, Clostridium XlVb , and Megamonas. In summary, our study characterized the effect of MTBE on adipose tissue function and glucose homeostasis in vitro and in vivo , and revealed that systemic disorders of the glucose metabolism might be modulated by the related gut microbiota. Unlabelled Image [ABSTRACT FROM AUTHOR]

A single-stage synthesis of isoprene from methyl tert-butyl ether (MTBE) and formalin in an organic-aqueous two-phase system was studied by using solid acid catalysts, i.e., USY zeolite, silicotungstic acid (STA) 25 wt% encapsulated in MIL-101(Cr) (STA25@MIL-101), and STA 25 wt% encapsulated in SBA-15 (STA25@SBA-15). From preliminary experiments, the catalytic activity decreased in the order: STA25@MIL-101 > SBA25@SBA-15 > USY zeolite. This suggested that isoprene formation was favored with high surface area and high acid strength of catalyst. Then, the porous hybrid material of a MIL-101 metal organic framework and STA was studied in more detail. MIL-101 was not efficient for isoprene synthesis at mild reaction condition. On increasing STA loading, which was well correlated with the Brӧnsted acid property, the catalyst activity increased in the order: MIL-101 < STA30@MIL-101 < STA60@MIL-101. The high acidity catalyst gave high isoprene yield at optimum low temperature and low side reaction products. For the STA30@MIL-101 and STA60@MIL-101 catalysts, the isoprene yield could be sustained at 18.5% (0.4% SD) and 30.0% (1.5% SD), respectively over three recycling runs. It is apparent that no STA leaching from the low STA loading catalyst occurred. [ABSTRACT FROM AUTHOR]

Copyright of Zentralblatt fuer Arbeitsmedizin, Arbeitsschutz und Ergonomie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was conducted to identify the correlation between the CO chemisorption (linear interaction and gem dicarbonyl) and the specific size of rhodium particles, and further to determine the influence of this relationship on the catalytic oxidation reaction of methyl tert-butyl ether (MTBE). During the synthesis, first, TiO2 was developed by the sol-gel method under acidic conditions. Second, Rh was deposited (1 wt %) by the incipient wetness impregnation method. Later, with the aim of controlling the particle size, the Rh/TiO2 materials were crystallized at different reduction conditions during 3 h heat treatment. The results obtained by TEM micrographs indicated that the average particle size varies between 1.0 and 8.1 nm, depending on the conditions of heat treatment. From the histogram analysis of each TEM micrograph, two correlations were made: (i) the gem-dicarbonyl interaction was typical of Rh particles ≤ 1.5 nm, and (ii) a linear interaction, bridged interaction and dentate interaction were observed in particles ≥ 1.6 nm. The gem-dicarbonyl interaction (particle size ≤ 1.5 nm) was the most active in the oxidation reaction of MTBE. [ABSTRACT FROM AUTHOR]

The widespread use of MTBE facilitates its entrance to the environment. Therefore, it is necessary to achieve a suitable method for the elimination of this carcinogenic contaminant. This study was conducted to investigate the MTBE removal from aqueous solution by ultraviolet activated persulfate (PS) based AOP. The solutions containing MTBE were synthesized at the concentrations of 10, 50 and 100 mg/L, and the rate of the removal efficiency was evaluated under the process conditions including pH: 3, 5, 7 and 9, PS concentration: 5, 10 and 20 mg/L and retention time: 30, 60, 120, 200 and 300 min. The results of this study showed that MTBE removal in the UV/PS process was pH dependent and the performance was better in neutral and acidic conditions. It was also found that, with increasing the PS concentration and decreasing initial MTBE concentration, better removal efficiency was achieved. Moreover, MTBE decomposition followed the first-order equation and this process was successful in reducing organic carbon. In conclusion, the UV/PS system can be considered as an effective process for eliminating the resistant pollutants such as MTBE. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to investigate the comparative effects of oxygenates such as ethanol (EA), methyl tertiary-butyl ether (MTBE), and ethyl tertiary butyl ether (ETBE) by fixing the oxygen contents as 0.82 wt% 1.65 wt%, and 2.74 wt% of the fuels on the regulated (CO, NMHC and NO x) and unregulated (formaldehyde, acetaldehyde and BTEX) exhaust emissions in gasoline-powered vehicles. The most widely used type of vehicles (light-duty, medium-duty, heavy-duty) in Korea were tested on a chassis dynamometer under the CVS-75 Cycle. When EA, MTBE and ETBE percentage increased, the CO and NMHC concentration decreased. The NO x emission decreased at 1.65 wt% and 2.74 wt% oxygen content of MTBE and ETBE. The emissions of CO decreased by 0.363 g/km, 0.266 g/km and 0.356 g/km for light-duty vehicle when EA, MTBE and ETBE oxygenates blending ratio increased. Increased EA, MTBE and ETBE oxygenates blending ratio demonstrated no specific reducing effect on CO emissions from low-mileage vehicle, but NMHC emissions decreased by 0.011 g/km (medium-duty), 0.015 g/km (light-duty) and 0.018 g/km (heavy-duty). More CO was emitted from MTBE among three oxygenates at same oxygen content. The emitted concentrations of NMHC from three oxygenates at same oxygen content were almost similar, but reduced NO x emissions from EA (10%) to MTBE (20.4%) and ETBE (23.6%) were observed at 2.74 wt% oxygen content. Reducing effect on CO emissions was order of EA > ETBE > MTBE. Formaldehyde emissions increased up to 54.3% as MTBE ratio increased. When oxygen content of ETBE, EA, and MTBE increased from 0.82 wt% to 2.74 wt%, the acetaldehyde emissions increased up to 177.4%, 39.5% and 31.0%, respectively. There was significant formaldehyde concentration difference between high emission vehicle type (light-duty and medium-duty) and low emission vehicle type (heavy-duty and low-mileage) for three oxygenates. Reduction effect of MTBE and ETBE on BTEX was the order of toluene > benzene > ethylbenzene > xylene, and MTBE showed more reduction effect than ETBE at same oxygen content. Graphical abstract Figure Chassis dynamometer test on exhaust emissions from oxygenates blended gasoline. Image 1 Highlights • The effects of oxygenates on the regulated and unregulated emissions from gasoline vehicles were investigated. • CO and NMHC were decreased by EA, MTBE and ETBE percentage increase. • EA or ETBE addition increased acetaldehyde emission, and MTBE addition increased formaldehyde emission. • Reduction effect of MTBE and ETBE on BTEX showed the same order of toluene > benzene > ethylbenzene > xylene. [ABSTRACT FROM AUTHOR]

Highlights • LLE data of methyl tert-butyl ether + methanol + IL systems were measured. • The NRTL and UNIQUAC models were applied to correlate the studied system. • Influence of temperature on the LLE was discussed. Abstract Searching for green solvents is imperative for the sustainable development of liquid-liquid extraction. Liquid-liquid equilibrium data for two ternary systems of methyl tert-butyl ether (MTBE) + methanol + N-methylimidazolium hydrosulfate ([MIM][HSO 4 ]) and MTBE + methanol + 1-butyl-3-methylimidazolium hydrosulfate ([BMIM][HSO 4 ]) were measured at 278.15 K, 298.15 K and 318.15 K at 101.325 kPa for this study. The values of the distribution coefficient and the separation factor were calculated based on the experimental data, and then, the extraction ability was determined. Factors affecting the phase behavior such as the nature of the ionic liquid and the temperature were discussed. NRTL and UNIQUAC models were applied to correlate the experimental tie-line data. [ABSTRACT FROM AUTHOR]

The use of the gasoline additive methyltert‐butyl ether (MTBE) has caused serious concern about groundwater and surface water contamination. In this study, UV light/ NiO nano‐photocatalyst (NiONP) system was firstly used to degradation of MTBE in contaminated water. A low‐cost and environmentally clean exploded‐wire plasma technique based on cheap solid nickel source is developed for preparation of NiONP. Optical, magnetic and physicochemical properties were successfully characterized using DRS, VSM, XRD, SEM, EDX, TEM and BET techniques. The NiONP exhibits excellent photocatalytic degradation ability of MTBE. The degradation process was monitored during the photocatalytic reaction by gas chromatography‐mass spectrometry (GC‐MS). It has been found that MTBE undergoes a series of intermediate step, which leads to form a number of intermediate products, mainly acetone, formic acid and t‐butyl formate (TBF). According to the results of the intermediates determination, a possible pathway degradation of MTBE was also proposed. [ABSTRACT FROM AUTHOR]

Abstract ZSM-5, as a hydrophobic zeolite, has a good adsorption capacity for methyl tert -butyl ether (MTBE) in batch adsorption studies. This study explores the applicability of ZSM-5 as a reactive material in permeable reactive barriers (PRBs) to decontaminate the MTBE-containing groundwater. A series of laboratory scale fixed-bed column tests were carried out to determine the breakthrough curves and evaluate the adsorption performance of ZSM-5 towards MTBE under different operational conditions, including bed length, flow rate, initial MTBE concentration and ZSM-5 dosage, and regeneration tests were carried out at 80, 150 and 300 °C for 24 h. Dose-Response model was found to best describe the breakthrough curves. MTBE was effectively removed by the fixed-bed column packed with a ZSM-5/sand mixture with an adsorption capacity of 31.85 mg g−1 at 6 cm bed length, 1 mL min−1 flow rate, 300 mg L−1 initial MTBE concentration and 5% ZSM-5 dosage. The maximum adsorption capacity increased with the increase of bed length and the decrease of flow rate and MTBE concentration. The estimated kinetic parameters can be used to predict the dynamic behaviour of column systems. In addition, regeneration study shows that the adsorption capacity of ZSM-5 remains satisfactory (>85%) after up to four regeneration cycles. Highlights • ZSM-5 is evaluated on its removal for MTBE in fixed-bed column tests. • Dose-Response model was found to best describe the breakthrough curves. • The removal capacity is ∼31.85 mg g−1 in fixed-bed column tests. • Parameters from BDST model can predict breakthrough curves at a new flow rate. • ZSM-5 is effective and recyclable for MTBE contaminated groundwater remediation. [ABSTRACT FROM AUTHOR]

Abstract Volatile Organic Compounds (VOCs) from vehicles are a significant contributor to Mexico's pollution, as a precursor to both ambient ozone and secondary particulate matter (PM). Recent updates to Mexico's gasoline specification NOM-016 allow ethanol blends up to 10 percent (E10) outside of the metropolitan areas of Mexico City, Guadalajara and Monterrey, and leave open the possibility of allowing E10 within these areas as well. The NOM-016 updates also permit E10 to have higher volatility (RVP) than previously allowed. The impact of these changes on vehicle emissions in Mexico was assessed, with a focus on evaporative VOC emissions driven by increased RVP and permeation. Roadside remote sensing (RSD) measurements from Mexico City were analyzed, finding that vehicle fleet hydrocarbon (HC) emissions are much higher than U.S. levels, with indication that high evaporative emissions contribute to this. The impact on vehicle emissions of the NOM-016 revisions and potential introduction of E10 in metropolitan zones was assessed for an ozone episode day using the MOVES-Mexico model, which reflects higher evaporative emissions from Mexico's vehicle fleet. Results show an increase in total motor vehicle VOC emissions of 13–18 percent in metropolitan areas and a 23 percent increase in other areas of the country for NOM-016 compliant E10 fuel, relative to fuel sold in Mexico prior to the NOM-016 update. Results for other pollutants showed an increase in PM 2.5 and air toxics from E10 blends, a reduction in CO, and NOx impacts mixed depending on area. Total motor vehicle emissions for toluene, identified in prior work as the compound with the highest ozone forming potential in Mexico City, increased by 29–34 percent with E10 fuel in Mexico City and more in other metropolitan areas. Past studies linking emissions change with health outcomes in Mexico City suggest that the increase in vehicle emissions from NOM-016 updates would have a measurable negative effect on premature mortality, chronic bronchitis, hospital visits, and restricted activity days, with societal costs associated with health care and lost productivity. Highlights • Mexico's vehicle emissions will be affected by new fuel specifications, including higher RVP limits for ethanol blends. • A new analysis of roadside remote sensing data suggests evaporative emissions contribute to high vehicle VOC in Mexico City. • Vehicle emissions were estimated by the MOVES-Mexico model run on base fuel vs. fuels compliant with the new standard. • Motor vehicle VOC is projected to increase 13-18 percent in urban areas when E10 with higher RVP is used. • E10 is also projected to increase urban PM 2.5 and air toxics, and decrease CO. NOx results are mixed depending on area. [ABSTRACT FROM AUTHOR]

Abstract Background The elucidation of complex biological systems requires integration of multiple molecular parameters. Accordingly, high throughput methods like transcriptomics, proteomics, metabolomics and lipidomics have emerged to provide the tools for successful system-wide investigations. Unfortunately, optimized analysis of different compounds requires specific extraction procedures in combination with specific analytical instrumentation. However, the most efficient extraction protocols often only cover a restricted number of compounds due to the different physico-chemical properties of these biological compounds. Consequently, comprehensive analysis of several molecular components like polar primary metabolites next to lipids or proteins require multiple aliquots to enable the specific extraction procedures required to cover these diverse compound classes. This multi-parallel sample handling of different sample aliquots is therefore not only more sample intensive, it also requires more time and effort to obtain the required extracts. Results To circumvent large sample amounts, distributed into several aliquots for the comprehensive extraction of most relevant biological compounds, we developed a simple, robust and reproducible two-phase liquid–liquid extraction protocol. This one-step extraction protocol allows for the analysis of polar-, semi-polar and hydrophobic metabolites, next to insoluble or precipitated compounds, including proteins, starch and plant cell wall components, from a single sample. The method is scalable regarding the used sample amounts but also the employed volumes and can be performed in microcentrifuge tubes, enabling high throughput analysis. The obtained fractions are fully compatible with common analytical methods, including spectroscopic, chromatographic and mass spectrometry-based techniques. To document the utility of the described protocol, we used 25 mg of Arabidopsis thaliana rosette leaves for the generation of multi-omics data sets, covering lipidomics, metabolomics and proteomics. The obtained data allowed us to measure and annotate more than 200 lipid compounds, 100 primary metabolites, 50 secondary metabolites and 2000 proteins. Conclusions The described extraction protocol provides a simple and straightforward method for the efficient extraction of lipids, metabolites and proteins from minute amounts of a single sample, enabling the targeted but also untargeted high-throughput analyses of diverse biological tissues and samples.

Background: Methyl tert-butyl ether (MTBE) is a pollutant that causes deleterious effects on human and environmental health. Certain microbial cultures have shown the ability to degrade MTBE, suggesting that a novel bacterial species capable of degrading MTBE could be recovered. The goal of this study was to isolate, identify and characterize the members of a bacterial consortium capable of degrading MTBE. Results: The IPN-120526 bacterial consortium was obtained through batch enrichment using MTBE as the sole carbon and energy source. The cultivable fraction of the consortium was identified; of the isolates, only Stenotrophomonas maltophilia IPN-TD and Sphingopyxis sp. IPN-TE were capable of degrading MTBE. To the best of our knowledge, this report is the first demonstrating that S. maltophilia and Sphingopyxis sp. are capable of degrading MTBE. The degradation kinetics of MTBE demonstrated that S. maltophilia IPN-TD had a significantly higher overall MTBE degradation efficiency and rate (48.39 ± 3.18% and 1.56 ± 0.12 mg L-1 h-1, respectively) than the IPN-120526 consortium (38.59 ± 2.17% and 1.25 ± 0.087 mg L-1 h-1, respectively). The kinetics of MTBE removal by both cultures fit first-order and pseudo-first-order reaction models. Conclusions: These findings suggest that S. maltophilia IPN-TD in axenic culture has considerable potential for the detoxification of MTBE-contaminated water.

Membrane properties are determined by their morphology, which may be symmetric (dense) or asymmetric (dense/porous). Two membrane types based on the poly[(4,4′-oxydiphenylene)pyromelliteimide] (symmetric dense and asymmetric dense/porous) were prepared for a comparative study of morphology, physical properties, and transport characteristics in the pervaporation of methanol/MTBE mixture over a wide range of concentrations including the azeotropic composition. The asymmetric membrane is a good example of improving the transport properties of the polyimide by creating structure composed of a thin dense top layer on the surface of sponge-like microporous substrate. It was found that the use of the asymmetric membrane allows increasing the total flux in separation of azeotropic mixture by 15 times as compared with the dense membrane.

In this research, the 2D hydrodynamic and mass transport model, CE-QUAL-W2, is modified to simulate the fate and transport of volatile organic compounds (VOCs) in standing and flowing water bodies. The modifed model is applied to the Karkheh river-reservoir system. For this purpose, a subroutine model is added to the CE-QUAL-W2 source code to simulate the physical, chemical, and biological fate of VOCs in water bodies. In a second step, the VOC mass continuity model is employed to evaluate the performance of the modified CE-QUAL-W2 model. The results confirm the accuracy of the modified CE-QUAL-W2 model. The modified CE-QUAL-W2 model is employed to simulate the Karkheh river-reservoir responses in sudden MTBE spill in Karkheh water body. The effects of reservoir operation (withdraw values and locations) on MTBE fate and transport are investigated. The results show, compared to the old version of the CE-QUAL-W2, the modified version in which VOC evaporation is considered shows a reduction in MTBE concentration in the water body under investigation. Furthermore, the effects of such environmental parameters as wind speed, water temperature, and air temperature on MTBE fate and transport are evaluated. The results show that increasing wind speed and water temperature accelerate the evaporation rate of VOCs and decrease the reservoir cleanup time while reducing air temperature leads to reduced VOC evaporation rates and increased VOC concentration in the water body.

Methyl tertiary-butyl ether (MTBE) is a gasoline additive used to enhance gasoline octane. It is highly soluble in water and is known for its carcinogenicity; hence its high risk of groundwater contamination. The present study was mainly designed to investigate MTBE effect on gasoline solubility in water, determine the associated COD value, and identify the kinetics of MTBE elimination from water by the stripping method. The results show that the kinetics of MTBE elimination from water can be expressed by a first order equation with the rate constants obtained as 0.0055 min-1 and 0.0074 min-1 at the two stirring rates of 100 rpm and 250 rpm, respectively. These rate constants are evidently high and are indicative of the effectiveness of the stripping method in MTBE removal from water. A linear function was established between COD reduction with respect to time at room temperature at low stirring rates (100 rpm) but an exponential function at high stiring rates (250 rpm). The solubility of gasoline with different additives (MTBE, ethanol, methanol) in water was also investigated. The results revealed that gasoline solubility decreased from 90 mg/l to 80mg/l and 69 mg/l, respectively, in the presence of ethanol and methanol. This is while the solubility of MTBE-containing gasoline in water rose from 90 mg/l to 778 mg/l, which shows an 8-fold increase in solubility in water.

Abstract In the last decade, metabolomics has experienced significant advances in the throughput and robustness of analytical methodologies. Yet the preparation of biofluids and low-mass tissue samples remains a laborious and potentially inconsistent manual process, and a significant bottleneck for high-throughput metabolomics. To address this, we have compared three different sample extraction solvent systems in three diverse sample types with the purpose of selecting an optimum protocol for subsequent automation of sample preparation. We have investigated and re-optimised the solvent ratios in the recently introduced methyl tert-butyl ether (MTBE)/methanol/water solvent system (here termed modified Matyash; 2.6/2.0/2.4, v/v/v) and compared it to the original Matyash method (10/3/2.5, v/v/v) and the conventional chloroform/methanol/water (stepwise Bligh and Dyer, 2.0/2.0/1.8, v/v/v) using two biofluids (human serum and urine) and one tissue (whole Daphnia magna). This is the first report of the use of the Matyash method for extracting metabolites from the US National Institutes of Health (NIH) model organism D. magna. Extracted samples were analysed by non-targeted direct infusion mass spectrometry metabolomics or LC-MS metabolomics. Overall, the modified Matyash method yielded a higher number of peaks and putatively annotated metabolites compared to the original Matyash method (1–29% more peaks and 1–30% more metabolites) and the Bligh and Dyer method (4–20% more peaks and 1–41% more metabolites). Additionally the modified Matyash method was superior when considering metabolite intensities. The reproducibility of the modified Matyash method was higher than other methods (in 10 out of 12 datasets, compared to the original Matyash method; and in 8 out of 12 datasets, compared to the Bligh and Dyer method), based upon the observation of a lower mRSD of peak intensities. In conclusion, the modified Matyash method tended to provide a higher yield and reproducibility for most sample types in this study compared to two widely used methods. Highlights • Bligh and Dyer, Matyash and a new 'modified Matyash' solvent systems were compared. • Applied to three sample types and analysed by mass spectrometry-based metabolomics. • Modified Matyash showed comparable or higher extraction yield than other methods. • Reproducibility of modified Matyash method was also comparable or higher. [ABSTRACT FROM AUTHOR]

Destruction of methyl tert-butyl ether (MTBE) in liquid phase and in a batch reactor was studied using ruthenium catalysts over alumina support, modified with different cerium loadings. Ce loading increment causes an increase in the particle size from 1.26 nm to 2.3 nm, enhancing the MTBE oxidation (at 150 °C), and the selectivity toward CO2. The high catalytic activity of Ru/ACe10 is attributed to the species Ce4+-O2--M that could favor the oxygen transfer between the catalyst surface and the adsorbed species by a redox mechanism. Thus, CeOx plays an important role in both enhancing the affinity between MTBE and catalyst during MTBE adsorption and promoting the catalytic activity for MTBE oxidation. [ABSTRACT FROM AUTHOR]

In this study, sewage sludge-derived activated carbon (SDAC) was synthesized, characterized, and tested for its potential as an adsorbent of methyl tert-butyl ether (MTBE). The SDAC was produced by activating the sludge with zinc chloride and subsequently subjected to various ranges of pyrolytic temperatures. It was then characterized using SEM/EDX, BET, and TGA. The SEM-EDX analyses showed that impurities like Fe, Al, Mg, Mn, Ca, and Na of the raw sludge were removed by the higher pyrolytic temperature and acid-washing procedures. TGA showed the thermal stability of the produced material. Results of the BET revealed a significant increase in surface area of the sludge from 1.5 m2/g to 385 m2/g after acid washing. The MTBE removal efficiency of 70% was achieved after 60 min with 2 g/L of SDAC at pH 6, and initial MTBE concentration of 1 ppm. The adsorption kinetics of SDAC fitted into pseudo-second-order reactions. This work demonstrated a beneficial use of a bio-waste material (sewage sludge) in water treatment technologies. [ABSTRACT FROM AUTHOR]

Oxygenated fuels such as alcohols and ethers have the potential to provide reliable sources, and environmentally friendly fuel to world's increasing future energy demands. Oxygenated fuels have a promised future since are renewable and produced from several sources, also can be produced locally. The first objective of this paper is to systematically review of oxygenated fuels including alcohol and ether regarding the production, environmental impacts and potential using as octane booster of gasoline that used in spark ignition SI) engine. Another objective of this paper is to review the effects of oxygenated fuels on performances and emissions characteristics of spark ignition engine. Alcohol and ether burn very cleanly than regular gasoline and produce lesser carbon monoxide (CO) and nitrogen oxides (NO x ). Mainly the ether fuels (methyl tertiary butyl ether MTBE and Dimethyl Ether DME) are used as additives at low blending ratio to enhance the octane number and oxygen content of gasoline. Furthermore, alcohols and ethers have significant impacts on the environment, greenhouse gas and human health. In addition to this, application of oxygenated fuel on SI engines can decrease environmental pollution, strengthen agricultural economy and decrease gasoline fuel requirements. The increase in engine performance could be attained with an increased compression ratio along with the use of alcohol fuels which have a higher-octane value. Overall, oxygenated fuels have been found to be a very promising alternative fuel for SI engines, capable of providing high thermal efficiency, and lower NO x levels. [ABSTRACT FROM AUTHOR]

Methyl tertiary butyl ether (MTBE) is widely used as a gasoline additive. The contamination of surface water and groundwater with MTBE has attracted further attention due to the relatively high potential MTBE related health risks. In the current research, the adsorption capability of MTBE by kaolinite, bentonite, sandy loam and clay loam was studied through series of batch sorption procedures. The results were investigated with respect to the linear, Freundlich, Langmuir, Toth and Langmuir-Freundlich sorption isotherms. In the equilibrium condition, the MTBE concentration (Ceq) was 0.68-6.88 mg/L for clay loam, 0.89-8.94 mg/L for sandy loam, 1.3-11.26 mg/L for bentonite and 1.56-13.5 mg/L for kaolinite. The obtained modeling results revealed that the sorption affinity of the studied soils for MTBE increases in the order of kaolinite < bentonite < sandy loam clay loam. Moreover, the effects of contact time, pH, and temperature on the sorption affinity of MTBE into the soil samples were investigated and the thermodynamic parameters (ΔG, ΔH and ΔS) were calculated. Approximately 80% of the total MTBE removal was occurred within the first 80 min of experiments. Moreover, the maximum MTBE removal (57.4%) was obtained at pH of 3 while the least efficiency (23.1%) at pH of 11. A decrease in sorption distribution coefficient (Kd ) was observed with increasing the temperature and its maximum value was found at 298.15°K. According to our findings, different types of soils due to their acceptable efficiency and low cost could be applicable for the MTBE removal from the aqueous solutions. [ABSTRACT FROM AUTHOR]

The intensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in serious environmental problems due to its high solubility, volatility and recalcitrance. The feasibility of permeable reactive barriers (PRBs) with ZSM-5 type zeolite as a reactive medium was explored for MTBE contaminated groundwater remediation. Batch adsorption studies showed that the MTBE adsorption onto ZSM-5 follows the Langmuir model and obeys the pseudo-second-order model with an adsorption capacity of 53.55 mg g −1 . The adsorption process reached equilibrium within 24 h, and MTBE was barely desorbed with initial MTBE concentration of 300 mg L −1 . The mass transfer process is found to be primarily controlled by pore diffusion for MTBE concentrations from 100 to 600 mg L −1 . pH has little effect on the maximum adsorption capacity in the pH range of 2–10, while the presence of nickel reduces the capacity with Ni concentrations of 2.5–25 mg L −1 . In fixed-bed column tests, the Dose-Response model fits the breakthrough curve well, showing a saturation time of ∼320 min and a removal capacity of ∼18.71 mg g −1 under the conditions of this study. Therefore, ZSM-5 is an extremely effective adsorbent for MTBE removal and has a huge potential to be used as a reactive medium in PRBs. [ABSTRACT FROM AUTHOR]

The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl alcohol (TBA, a possible oxygenate metabolite), was studied at an industrially contaminated site and in the laboratory. Analysis of groundwater samples indicated that in the field MtBE was degraded, yielding TBA as major product. In batch microcosms, MtBE was degraded under different conditions: unamended control, with medium without added electron acceptors, or with ferrihydrite or sulfate (with or without medium) as electron acceptor, respectively. Degradation of EtBE was not observed under any of these conditions tested. TBA was partially depleted in parallel with MtBE. Results of microcosm experiments with MtBE substrate analogues, i.e., syringate, vanillate, or ferulate, were in line with the hypothesis that the observed TBA degradation is a cometabolic process. Microcosms with ferulate, syringate, isopropanol, or diethyl ether showed EtBE depletion up to 86.5% of the initial concentration after 83 days. Benzene was degraded in the unamended controls, with medium without added electron acceptors and with ferrihydrite, sulfate, or chlorate as electron acceptor, respectively. In the presence of nitrate, benzene was only degraded after addition of an anaerobic benzene-degrading community. Nitrate and chlorate hindered MtBE, EtBE, and TBA degradation. [ABSTRACT FROM AUTHOR]

The contamination of underground water by methyl tertiary butyl ether (MTBE) is a very serious environmental issue as its separation from the water is quite difficult because of high solubility. Limited studies have used ceria composite as a catalyst for the photo-degradation of MTBE in water samples. Therefore, photo-degradation of aqueous MTBE using synthesized pure ceria and copper oxide-ceria composite nanofiber catalyst was conducted in the present study under UV irradiation. The binary catalyst (with 0–20% Cu loading) was prepared via electrospinning method, and characterized using SEM, EDX, FTIR, XPS, BET surface area and XRD techniques. The morphology of such prepared catalyst was confirmed by scanning electron microscopy (SEM), whereas, the copper loading in the composite was assured by EDX (Electron dispersive X-ray spectroscopy). This experiment was performed using aqueous MTBE solution of various initial concentrations (100–400 ppm) for a time period of 2 h, and the optimization of operational parameters was done. The study showed that the maximum efficiency to degrade 100 ppm of MTBE under UV irradiation was achieved at pH 8.0 with a catalyst loading of 1 g/L following first order reaction kinetics. Thus, this composite presents a novel catalyst for effective purification of MTBE contaminated water. Similar studies using other nano-composite materials as catalyst are recommended for identifying effective methods of water purification in a simple and cost effective manner. [ABSTRACT FROM AUTHOR]

Simulation of reactive distillation by using special engineering software is promising way to its design, research and optimization. In this work we considered the industrial-scale facility of Western Siberia, which includes a line of methyl tert-butyl ether production in a reactive distillation unit. Aspen HYSYS® was used as an instrument of simulation and further optimization studies. The calculation error of the model does not exceed 5%. Simulation of the feedstock composition changes showed that more preferable hydrocarbon fraction for the process is isobutene-isobutylene fraction. After the optimization study we obtained values of optimal reflux ratio for isobutene-isobutylene fraction to be 0.75 and for butylene-isobutylene fraction - 0.80; optimal methanol flowrate for isobutene-isobutylene fraction is 6.500 ton/h, for butylene-isobutylene fraction-6.000 ton/h. [ABSTRACT FROM AUTHOR]

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Fatty acids (FAs) are used, often in combination with stable isotopes (SIs), as chemical biomarkers to assess the contribution of different prey to the diet of consumers and define food web structure and dynamics. Extraction of lipids is traditionally carried out using methanol (MeOH) combined with chloroform or dichloromethane, these latter being well-known environmental pollutant and potential carcinogenic agents. Recently, extraction protocols based on methyl tert -butyl ether (MTBE) and MeOH have been proposed as an alternative to halogenated solvents in lipidomic studies. However, no specific investigation has been performed to assess MTBE suitability in marine ecological studies including FA analysis together with SI measurements. We used an analytical workflow for qualitative and quantitative analysis of FAs and SIs in field samples of phytoplankton, zooplankton and the scyphomedusa Pelagia noctiluca , applying MTBE in comparison with chloroform- and dichloromethane-based protocols for total lipid extraction. Our analysis suggested that MTBE is a reliable substitute for lipid extraction in trophic ecology studies in marine planktonic organisms. • Fatty acids (FAs) and stable isotopes (SIs) are biomarkers used to define food web structure. • Conventional lipid extraction protocols mostly rely on harmful halogenated solvents. • A MTBE-based protocol has been applied to three groups of marine planktonic organisms. • FAs and SIs data from MTBE, CHCl 3 and CH 2 Cl 2 extraction protocols have been compared. • MTBE is a reliable and safer alternative for lipid extraction in trophic ecology studies. [ABSTRACT FROM AUTHOR]

Hydrocarbon contamination of water resources is a global issue. These compounds are generated and discharged into the environment in industrial areas from chemical and petrochemical plants, oil refineries, power plants, and so forth. Fuel hydrocarbons, namely, BTEX (benzene, toluene, ethylbenzene, and xylenes) and MTBE (methyl tert-butyl ether), are commonly found in groundwater, posing environmental and health risks to humans and ecosystems. Nature-based technologies represent an alternative solution, providing high efficiency, an environmentally friendly character, simple operation, and cost efficiency, which are characteristics particularly desired by the international petroleum industry. This article discusses the use of the green technology of constructed wetlands to remediate water polluted with hydrocarbons. Although the number of related international experiences and studies is limited, the article presents the latest developments of wetland technology for the removal of MTBE and benzene-BTEX. The discussion includes the overall efficiency of the different wetland types that have been tested and used, the main transformation and removal processes that regulate the fate of BTEX and MTBE in constructed wetlands, and the potential for future investigations.

Intentional and/or accidental volatile organic compound (VOC) spill into water bodies may lead to severe contamination and health problems in water infrastructures. The importance and widespread use of petroleum products and the threats posed by these products on surface water resources in Iran necessitates the access to numerical hydrodynamic and water quality simulation models with appropriate capabilities. Simulation the fate and transport of VOC in both flowing and standing water bodies is a fairly complex problem. In this research, CE-QUAL-W2 model is modified to simulate the fate and transport of VOC [i.e., Methyl tert-butyl ether (MTBE), benzene] in standing and flowing water bodies. The performance of the modified CE-QUAL-W2 model is evaluated in a MTBE pollution spill at Khalife-Tarkhan river along the headwaters of Gheshlagh reservoir, Kordestan, Iran. The results show the modified CE-QUAL-W2 model's capability to depict the spatial and temporal variation of MTBE in comparison with recorded data from MTBE spill event of Gheshlagh reservoir. Based on the simulation results of modified CE-QUAL-W2 model, reservoir cleanup time in different meteorological and hydrological scenarios is evaluated. The results show Gheshlagh reservoir cleanup time reduced in scenarios that included air temperature reduction, wind speed increasing, and high inflow condition. [ABSTRACT FROM AUTHOR]