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Methyl tert-butyl ether (MTBE) is a widely used gasoline additive. It is considered an endocrine-disrupting chemical. Whether MTBE affects the development of Leydig cells in late puberty of males and its underlying mechanism remains unclear. Twenty-four male Sprague-Dawley rats (35 days old) were randomly allocated into four groups and were orally given MTBE (0, 300, 600, and 1200 mg/kg/day) from postnatal day (PND) 35–56. MTBE markedly reduced serum testosterone levels at 300 mg/kg and higher doses without altering the serum levels of luteinizing hormone and follicle-stimulating hormone. It mainly inhibited cell proliferation, induced mitochondrial autophagy and apoptosis, and indirectly stimulated Sertoli cells to secrete anti-Müllerian hormones, thereby significantly reducing the number of Leydig cells at 1200 mg/kg. MTBE also markedly down-regulated the expression of mature Leydig cell biomarker Cyp11a1 and Hsd3b1 and their proteins, while up-regulating the expression of immature Leydig cell biomarker Akr1c14 and its protein at 600 mg/kg and higher. MTBE significantly down-regulated the expression of cell cycle gene Ccnd1, antioxidant gene Gpx1, and anti-apoptotic gene Bcl2, while increasing pro-apoptotic gene Bax level at 1200 mg/kg. In vitro study further confirmed that MTBE can inhibit testosterone synthesis by inducing reactive oxygen species (ROS) generation, mitophagy, and apoptosis at 200 and 300 mM. In conclusion, exposure to MTBE compromises the development of Leydig cells in late puberty in male rats.

El trabajo fue realizado en el Laboratorio de Combustibles y Lubricantes del Instituto Nacional de Tecnología, Normalización y Metrología – INTN, en el marco del proyecto 14-INV-193, financiado por el CONACYT y el INTN. Este proyecto tuvo como objetivos monitorear los niveles de benceno, hidrocarburos aromáticos y compuestos oxigenados (éteres y alcoholes) en muestras de gasolinas importadas en el país, mediante técnicas normalizadas por la ASTM y establecidas como métodos de referencia por el Ministerio de Industria y Comercio. El periodo de estudio abarca desde febrero de 2016 a julio de 2017. Los resultados obtenidos en promedio, se encontraron dentro de los límites establecidos en la legislación vigente, aunque se observaron casos puntuales donde excedieron los límites permitidos. Estos datos son importantes para tener un diagnóstico de la situación en cuanto a niveles de compuestos nocivos para el medioambiente y la salud humana, así como para la toma de decisiones de entes reguladores

We investigated the early risk of developing cancer by inhalation of low doses (60 &micro, L/day) of methyl tertiary butyl ether (MTBE) vapors using protein SDS-PAGE and LC-MS/MS analysis of rat sera. Furthermore, histological alterations were assessed in the trachea and lungs of 60 adult male Wistar rats. SDS-PAGE of blood sera showed three protein bands corresponding to 29, 28, and 21 kDa. Mass spectroscopy was used to identify these three bands. The upper and middle protein bands showed homology to carbonic anhydrase 2 (CA II), whereas the lower protein band showed homology with peroxiredoxin 2. We found that exposure to MTBE resulted in histopathological alterations in the trachea and the lungs. The histological anomalies of trachea and lung showed that the lumen of trachea, bronchi, and air alveoli packed with free and necrotic epithelial cells (epithelialization). The tracheal lamina propria of lung demonstrated aggregation of lymphoid cells, lymphoid hyperplasia, hemorrhage, adenomas, fibroid degeneration, steatosis, foam cells, severe inflammatory cells with monocytic infiltration, edema, hemorrhage. Occluded, congested, and hypertrophied lung arteries in addition, degenerated thyroid follicles, were observed. The hyaline cartilage displayed degeneration, deformation, and abnormal protrusion. In conclusion, our results suggest that inhalation of very low concentrations of the gasoline additive MTBE could induce an increase in protein levels and resulted in histopathological alterations of the trachea and the lungs.

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

In this work we propose and investigate an innovative groundwater remediation option based on the combination of catalyzed hydrogen peroxide (H 2 O 2 ) with CO 2 sparging. The effectiveness of this new process was evaluated by carrying out lab-scale tests on a soil–water system spiked with Methyl Tertiary Butyl Ether (MtBE). The results achieved with the combined process, evaluated in terms of H 2 O 2 lifetime and MtBE residual concentration in the liquid phase, were then compared with those obtained using H 2 O 2 only or amended with KH 2 PO 4 as stabilizing agent. The experimental results showed that the combined H 2 O 2 –CO 2 process has basically two beneficial effects. On the one hand, fluxing CO 2 into the oxidizing solution can lead to a pH decrease to acidic values that enhance the H 2 O 2 stability. Indeed, from the results obtained in the stability tests carried out, it was observed that the hydrogen peroxide lifetime in the combined H 2 O 2 –CO 2 process proved to be longer than the one achieved in the tests carried out with H 2 O 2 only, although slightly lower than the one achieved using KH 2 PO 4 as stabilizing agent. On the other hand, it was observed that with respect to a traditional chemical oxidation application, the CO 2 sparging can further enhance the overall effectiveness of the process as a result of contaminant stripping by CO 2 . Indeed, the residual MtBE concentration observed after application of the combined H 2 O 2 –CO 2 process was slightly lower than the ones obtained using H 2 O 2 only or comparable to the one achieved using H 2 O 2 amended with KH 2 PO 4 . Overall, these results showed that the combined H 2 O 2 –CO 2 process could represent a promising alternative to traditional formulations, avoiding the use of chemical amendments, while leading to comparable residual contaminant’s concentration.

Methyl tert-butyl ether (MTBE) is a ground water contaminant with plausible carcinogenic properties. Mycobacterium sp. strain ENV421 cometabolically degrades MTBE and other ethers during the growth on propane as a carbon source. In this study, the 6.2 Mb genome of strain ENV421 was deciphered. The genome sequence revealed the presence of numerous putative propane catabolic genes including genes encoding hydrocarbon oxygenases and short chain alcohol dehydrogenases. These data provide the basis for the elucidation of propane metabolic pathways in strain ENV421 and its application for the remediation of ground water contaminated with toxic ethers.

In Situ Chemical Oxidation (ISCO) based on the Fenton's process is a proven technology for the treatment of groundwater contaminated by organic compounds. Nevertheless, the application of this treatment process to methyl tert-butyl ether (MtBE) is questioned, as there are concerns about its capacity to achieve complete mineralization. Many existing studies have focused on water contaminated by MtBE and are thus not representative of in situ treatments since they do not consider the presence of soil. In this work, the effectiveness of a Fenton-like process for MtBE treatment was proven in soil column tests performed at operating conditions (i.e., oxidant and contaminant concentration and flow rates) resembling those typically used for in situ applications. No MtBE by-products were detected in any of the tested conditions, thus suggesting that the tert-butyl group of MtBE was completely degraded. A mass balance based on the CO2 produced was used as evidence that most of the MtBE removed was actually mineralized. Finally, the obtained results show that preconditioning of soil with a chelating agent (EDTA) significantly enhanced MtBE oxidation.

BTEX compounds (benzene, toluene, ethylbenzene and xylenes) and methyl tert-butyl ether (MTBE) are some of the main constituents of gasoline and can be accidentally released in the environment. In this work the effect of bioaugmentation on the microbial communities in a bench scale aerobic biobarrier for gasoline contaminated water treatment was studied by 16S rRNA gene sequencing. Catabolic genes (tmoA and xylM) were quantified by qPCR, in order to estimate the biodegradation potential, and the abundance of total bacteria was estimated by the quantification of the number of copies of the 16S rRNA gene. Hydrocarbon concentration was monitored over time and no difference in the removal efficiency for the tested conditions was observed, either with or without the microbial inoculum. In the column without the inoculum the most abundant genera were Acidovorax, Bdellovibrio, Hydrogenophaga, Pseudoxanthomonas and Serpens at the beginning of the column, while at the end of the column Thauera became dominant. In the inoculated test the microbial inoculum, composed by Rhodococcus sp. CE461, Rhodococcus sp. CT451 and Methylibium petroleiphilum LMG 22953, was outcompeted. Quantitative PCR results showed an increasing in xylM copy number, indicating that hydrocarbon degrading bacteria were selected during the treatment, although only a low increase of the total biomass was observed. However, the bioaugmentation did not lead to an increase in the degradative potential of the microbial communities.

Understanding of complex biological systems requires the measurement, analysis and integration of multiple compound classes of the living cell, usually determined by transcriptomic, proteomic, metabolomics and lipidomic measurements. In this protocol, we introduce a simple method for the reproducible extraction of metabolites, lipids and proteins from biological tissues using a single aliquot per sample. The extraction method is based on a methyl tert-butyl ether: methanol: water system for liquid: liquid partitioning of hydrophobic and polar metabolites into two immiscible phases along with the precipitation of proteins and other macromolecules as a solid pellet. This method, therefore, provides three different fractions of specific molecular composition, which are fully compatible with common high throughput 'omics' technologies such as liquid chromatography (LC) or gas chromatography (GC) coupled to mass spectrometers. Even though the method was initially developed for the analysis of different plant tissue samples, it has proved to be fully compatible for the extraction and analysis of biological samples from systems as diverse as algae, insects, and mammalian tissues and cell cultures.

In this study, the removal efficiency of methyl tertiary butyl ether (MTBE) by: (1) UV-Titanium dioxide (UV/TiO2), (2) UV-Carbon Nanotubes (UV/CNT) and (3) 5% TiO2 impregnated on CNTs surface (UV/CNTs/5%TiO2) was investigated. Two types of UV irradiation were utilized in this study namely: UVA irradiating at wavelength of 365nm and UVC irradiating at a wavelength of 254 nm. Dosage of 20 mg of nano materials was used in these experiments. The fate of MTBE’s main degradation by-products were also investigated in this study. Results of the study showed that MTBE removal in the dark was very low for the three types of nano materials under the study conditions used. However, appreciable removal of MTBE was observed when using UV/TiO2 for both types of UV lights, with UVC showing slightly better than UVA. On the other hand, the removal of MTBE by UV/CNTs and UV/CNTs/TiO2 were much lower than that of UV/TiO2.

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. Electronic supplementary material The online version of this article (doi:10.1186/s13007-016-0146-2) contains supplementary material, which is available to authorized users.

It is generally believed that the retention of methyl tert-butyl ether (MTBE) by zeolites is positively correlated to the silica content of these materials. Nevertheless, highly dealuminated zeolites can contain relevant amounts of silanol groups. In this study, the effect of these point defects in a zeolite Y (SiO2/Al2O3 = 200) on the adsorption of MTBE was evaluated by means of infrared spectroscopy, supported by DFT calculations. The adsorption process is found to occur in two steps, involving isolated silanol sites and the siloxane network of the zeolite, respectively, with an average loading of 1.3 molecules per cage in the first and 1.3 molecules in the second stage. Both external and internal isolated silanol groups (stretching at 3746 and 3738 cm−1, respectively) are involved in the MTBE adsorption process with the formation of H-bonded complexes and associated shifts (516 and 358 cm−1, respectively), consistent with a H-bonding strength higher for external than for the internal ones. However, MTBE is more tightly adsorbed on the internal silanols as a result of the cage confinement effect. The band assigned to the methyl symmetric stretching of the CH3O− group can be used to discriminate between H-bond and van der Waals MTBE−zeolite interactions (2843 and 2828 cm−1, respectively). Ab initio models were used to compute the harmonic frequencies of different MTBE−zeolite models and to simulate the cage confinement of one and three ether molecules.

This research examines the feasibility of analyzing tree cores to detect benzene, toluene, ethylbenzene, and m, p, o-xylene (BTEX) compounds and methyl tertiary-butyl ether (MTBE) in groundwater in eastern Canada subarctic environments, using a former landfill site in the remote community of Happy Valley-Goose Bay, Labrador. Petroleum hydrocarbon contamination at the landfill site is the result of environmentally unsound pre-1990s disposal of households and industrial solid wastes. Tree cores were taken from trembling aspen, black spruce, and white birch and analyzed by headspace-gas chromatography-mass spectrometry. BTEX compounds were detected in tree cores, corroborating known groundwater contamination. A zone of anomalously high concentrations of total BTEX constituents was identified and recommended for monitoring by groundwater wells. Tree cores collected outside the landfill site at a local control area suggest the migration of contaminants off-site. Tree species exhibit different concentrations of BTEX constituents, indicating selective uptake and accumulation. Toluene in wood exhibited the highest concentrations, which may also be due to endogenous production. Meanwhile, MTBE was not found in the tree cores and is considered to be absent in the groundwater. The results demonstrate that tree-core analysis can be useful for detecting anomalous concentrations of petroleum hydrocarbons, such as BTEX compounds, in subarctic sites with shallow unconfined aquifers and permeable soils. This method can therefore aid in the proper management of contamination during landfill operations and after site closures.

9 pages, 5 figures, 2 tables.-- PMID: 15350404 [PubMed].-- Printed version published Nov 2004., Negligible information is currently available concerning levels of the fuel additive methyl tert-butyl ether (MTBE) in European estuaries or coastal environments. MTBE was measured at selected potentially contaminated harbours and marinas, and throughout an axial transect of the Tamar Estuary, UK. Headspace solid-phase microextraction was used in combination with GC–MS for its determination. MTBE was detected in water samples from all stations at concentrations ranging from a few ng/l to a maximum of 194 ng/l (in a semi-enclosed harbour). Elevated levels were generally associated with motor vehicle and boating activities. The Tamar road and rail bridges provided a major input to the lower estuary, downstream of which conservative mixing appeared depressed, probably through volatilisation and possibly through salting-out. The selected analytical system (using a Carboxen/PDMS fiber) proved both rapid and highly sensitive (with a detection limit of 6 ng/l). During method development, salinity was shown to have a major influence in controlling the extraction efficiency and it was found necessary to adjust salinity in all samples (to 75% saturation) prior to extraction. From these tests, we (for the first time) estimated the Setschenow (“salting-out”) constant of MTBE to be 0.11 l/mol., This work was financially supported by the Catalonian Government.

Isobaric vapor liquid equilibrium (VLE) data were measured for the systems ethanol + 2,4,4-trimethyl-1-pentene and 2-propanol + 2,4,4-trimethyl-1-pentene at 101 kPa. The measurements were made with a recirculation still. The determination of the equilibrium compositions was made with two analyzers, a mass spectrometer, and a gas chromatograph. Two novel sampling systems were tested for introducing the samples of liquid and condensed vapor phases to the analyzers. The VLE data were correlated with the Wilson activity coefficient model and the Soave−Redlich−Kwong equation of state.

A series of simple and mixed oxides: SiO 2 , AlPO 4 , SiO 2 -Al 2 O 3 , TiO 2 , kaolin and γ-Al 2 O 3 differing by their basicities as characterised by effective negative charge on oxygen calculated according to Sanderson’s theorem was used for the preparation of supported H 4 SiW 12 O 40 catalysts. Using gas phase synthesis of MTBE as the catalytic test reaction it has been shown that on the supports of highest basicity, i.e. γ-Al 2 O 3 and kaolin the heteropolyacid was decomposed resulting in the catalyst which exhibited only low activity. On the other hand, the least basic oxide SiO 2 gave the most active catalysts. However, the sequence of activities differed from that of basicities by the fact that the activity of TiO 2 -supported catalyst was at the coverage with H 4 SiW 12 O 40 Θ =0.25 nearly as high as SiO 2 supported one and at Θ =1.0 TiO 2 -supported catalyst was the best. This indicates that the basicity of the support is only one of the factors determining the activity of supported heteropolyacid catalysts in acid–base type reactions. On the other hand good correlation was obtained between the catalytic activity and the neutralisation heat of the acid sites on the surface of catalyst which was determined using thermometric titration with n -butylamine solution in toluene.

The temperature-induced desorption of methyl tert-butyl ether (MTBE) from aqueous solutions onto hydrophobic ZSM-5 was studied by in situ synchrotron powder diffraction and chromatographic techniques. This kind of information is crucial for designing and optimizing the regeneration treatment of such zeolite. The evolution of the structural features monitored by full profile Rietveld refinements revealed that a monoclinic (P21/n) to orthorhombic (Pnma) phase transition occurred at about 100 °C. The MTBE desorption process caused a remarkable change in the unit-cell parameters. Complete MTBE desorption was achieved upon heating at about 250 °C. Rietveld analysis demonstrated that the desorption process occurred without any significant zeolite crystallinity loss, but with slight deformations in the channel apertures.

Methyl tert-butyl ether (MTBE) is used at significant percentages as an additive of unleaded gasoline. The physical-chemical properties of the substance (water solubility, soil organic carbon-water partition coefficient) cause high mobility and high concentrations in groundwater. Laboratory scale batch and column tests and mathematical modeling were performed to study the feasibility of a biobarrier (BB), that is an in situ permeable biological barrier with or without inoculation, for the remediation of MTBE and other gasoline-derived pollutants (benzene, toluene, ethylbenzene, o-xylene and m+p-xylenes, BTEXs) polluted groundwater and to estimate kinetic constants. The experimental results showed simultaneous biodegradation of MTBE and BTEXs, with similar removals in the uninoculated and the inoculated systems. Ranges for the first order kinetic removal were obtained for MTBE ((0.18±0.02)/(0.28±0.11d(-1))), B ((0.39±0.12)/(0.56±0.12d(-1))), T ((0.51±0.03)/(0.78±0.15d(-1))), E ((0.46±0.18)/(1.57±0.21d(-1))), o-X ((0.24±0.08)/(0.64±0.09d(-1))) and m+p-X ((0.20±0.04)/(1.21±0.04d(-1))). The results of the laboratory tests allowed to improve mathematical modeling in order to design a full-scale BB at a gasoline-contaminated site.

A great interest has arisen in establishing the impact of organic compounds on human health and air quality, especially those compounds emitted by automotive traffic. Knowledge of urban air pollutant concentrations is essential for the determination of exposure levels. With this information public health problems can be avoided and emissions sources can be identified. MTBE is one of such compound because of its effects both to the environment and to humans. In Costa Rica, as in many other parts of the world, MTBE has been added to gasoline up to 10% v/v. This study investigates ambient air concentration of MTBE in San Jose, Costa Rica. Samples were collected during October-December 2005 using Carbotrap® cartridges and analyzed by thermal desorption combined with capillary gas chromatography. MTBE levels ranged from < 0.1 to 7.0 ppbv, with the highest concentrations observed in the wet season's months (May to November). The highways and industrial areas were identified as MTBE's point sources, both related with vehicle emissions. High levels of MTBE were also found in the vicinity of a gas station. These values represent the first measurements made in a Central American location, but are similar to those reported in other urban areas. The MTBE ambient air levels in San Jose, Costa Rica were not known until this study in 2005. Ha surgido un gran interés en establecer el impacto de los compuestos orgánicos sobre la salud humana y la calidad del aire, especialmente aquellos compuestos emitidos por el tráfico automotor. El conocimiento de las concentraciones de contaminantes atmosféricos urbanos es fundamental para determinar los niveles de exposición. Con esta información se pueden evitar problemas de salud pública y se pueden identificar las fuentes de emisiones. El MTBE es uno de estos compuestos debido a sus efectos tanto en el medio ambiente como en los seres humanos. En Costa Rica, como en muchas otras partes del mundo, se ha agregado MTBE a la gasolina hasta un 10% v / v. Este estudio investiga la concentración de MTBE en el aire ambiental en San José, Costa Rica. Las muestras se recolectaron durante octubre-diciembre de 2005 utilizando cartuchos Carbotrap® y se analizaron mediante desorción térmica combinada con cromatografía de gases capilar. Los niveles de MTBE variaron de

The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). Besides, specific surface area was also determined by BET method. The four effective factors including pH of the reaction mixture, Fe3O4/ZnO magnetic nanoparticles concentration, initial MTBE concentration and molar ratio of [H2O2]/ [MTBE] were optimized using response surface modeling (RSM). Using the four-factor-three-level Box–Behnken design, 29 runs were designed considering the effective ranges of the influential factors. The optimized values for the operational parameters under the respective constraints were obtained at PH of 7.2, Fe3O4/ZnO concentration of 1.78 g/L, initial MTBE concentration of 89.14 mg/L and [H2O2]/ [MTBE] molar ratio of 2.33. Moreover, kinetics of MTBE degradation was determined under optimum condition. The study about core/shell magnetic nanoparticles (MNPs) recycling were also carried out and after about four times, the percentage of the photocatalytic degradation was about 70%.

Vertical flow systems filled with porous medium have been shown to efficiently remove volatile organic contaminants (VOCs) from contaminated groundwater. To apply this semi-natural remediation strategy it is however necessary to distinguish between removal due to biodegradation and due to volatile losses to the atmosphere. Especially for (potentially) toxic VOCs, the latter needs to be minimized to limit atmospheric emissions. In this study, numerical simulation was used to investigate quantitatively the removal of volatile organic compounds in two pilot-scale water treatment systems: an unplanted vertical flow filter and a planted one, which could also be called a vertical flow constructed wetland, both used for the treatment of contaminated groundwater. These systems were intermittently loaded with contaminated water containing benzene and MTBE as main VOCs. The highly dynamic but permanently unsaturated conditions in the porous medium facilitated aerobic biodegradation but could lead to volatile emissions of the contaminants. Experimental data from porous material analyses, flow rate measurements, solute tracer and gas tracer test, as well as contaminant concentration measurements at the boundaries of the systems were used to constrain a numerical reactive transport modeling approach. Numerical simulations considered unsaturated water flow, transport of species in the aqueous and the gas phase as well as aerobic degradation processes, which made it possible to quantify the rates of biodegradation and volatile emissions and calculating their contribution to total contaminant removal. A range of degradation rates was determined using experimental results of both systems under two operation modes and validated by field data obtained at different operation modes applied to the filters. For both filters, simulations and experimental data point to high biodegradation rates, if the flow filters have had time to build up their removal capacity. For this case volatile emissions are negligible and total removal can be attributed to biodegradation, only. The simulation study thus supports the use of both of these vertical flow systems for the treatment of groundwater contaminated with VOCs and the use of reactive transport modeling for the assessment of VOCs removal and operation modes in these high performance treatment systems.

Methyl tert-butyl ether (MTBE) is one of most commonly used oxygenates added to replace toxic compounds from gasoline and to reduce air pollutants emission. Due to intensive use and persistence, MTBE has become one of the most important environment pollutants. Presented research shows the capability of bacterial isolate Kocuria sp. 27/1 of biodegradation of MTBE as a additional source of carbon and energy. The obtained results shows that Kocuria sp. 27/1 was capable of utilizing of different initial concentrations of MTBE added as additional carbon and energy source. After 86 days of incubation on rotary shaker at 110 rpm and 27 °C, degradation rates of initial 25; 125 and 250 μg concentrations MTBE x ml-1 were 32; 28 and 62%, respectively. Highest degradation rate at all examinated concentrations was noticed in the beginning of incubation period. During the incubation increasing of bacterial number in all treatments was noticed, but this increasing was very slow, probably because of intermedier(s) during degradation and recalcitrance of C-atom. This research confirms the potential use of Kocuria sp. 27/1 in bioremediation of MTBE-contaminated environments. Metil tercijarni butil etar (MTBE) je jedan od najčešće korišćenih oksigenata koji je dodat benzinu u cilju zamene toksičnih komponenti i redukcije aerozagađenja. Zbog intenzivne upotrebe i otpornosti, MTBE je postao jedan od najvažnijih polutanata u čovekovoj sredini. Ova istraživanja pokazala su potencijal bakterijskog izolata Kocuria sp. 27/1 u biodegradaciji MTBE-a kao dounskog izvora ugljenika i energije. Dobijeni rezultati pokazuju da je Kocuria sp. 27/1 bila sposobna da koristi različite početne koncentracije MTBE-a dodatog kao dopunski izvor ugljenika i energije. Posle 86 dana inkubacije u orbitalnom šejkeru pri 110 rpm i 27 °C, stepen degradacije početnih koncentracija MTBE-a (25, 125 i 250 μg x ml-1) iznosio je između 28 i 62%. Najveći stepen degradacije u svim ispitivanim koncentracijama zabeležen je na početku inkubacionog perioda. Tokom inkubacije konstatovan je porast broja bakterija, ali je ovaj porast bio veoma slab, što je verovatno povezano sa nastankom intermedijera tokom degradacije i otpornošću C atoma. Ova istraživanja potvrđuju potencijalnu primenu bakterije Kocuria sp. 27/1 u bioremedijaciji ekosistema kontaminiranih MTBE-om.

Methyl-tert-butyl ether (MTBE) has been used to replace the toxic compounds from gasoline and to reduce emission of air pollutants. Due to its intensive use, MTBE has become one of the most important environment pollutants. The aim of this study was the isolation and identification of the bacteria from wastewater sample of 'HIP Petrohemija', Pančevo (Serbia), capable of MTBE biodegradation. The results of the investigation showed that only the bacterial isolate 27/1 was capable of growth on MTBE. The result of sequence analyzes of 16S rDNA showed that this bacterial isolate belongs to the Kocuria sp. After the incubation period of 86 days, the degradation rates of initial MTBE concentration of 25 and 125 μg/ml were 55 and 36%, respectively. These results indicated that bacteria Kocuria sp. is successfully adapted on MTBE and can be potentially used in bioremediation of soils and waters contaminated with MTBE. Metil tercijarni butil etar (MTBE) uveden je u proizvodnju s ciljem zamene toksičnih komponenti iz benzina, povećanja oktanskog broja goriva i redukcije aerozagađenja. Usled intenzivne primene, perzistentnosti i mobilnosti, MTBE je posle svega nekoliko godina postao značajan polutant u životnoj sredini. Cilj ovog rada je izolacija i identifikacija bakterija iz uzorka otpadne vode poreklom iz 'HIP Petrohemije', Pančevo, sposobnih da vrše degradaciju MTBE-a. Od 11 bakterijskih izolata, svrstanih u tri grupe po morfološkim osobinama, samo je jedan izolat, označen kao 27/1, pokazao sposobnost rasta na MTBE-u kao jedinstvenom izvoru ugljenika i energije i odabran je za dalja istraživanja. Ovaj izolat ima sitne crvenkaste kolonije na podlozi 0,1×TSA. Ćelije su okruglastog oblika, ne stvaraju spore a po Gramu se boje pozitivno. Primenom API i APIWEB sistema, ovaj izolat pokazuje najveći stepen sličnosti sa bakterijskom vrstom Kocuria rosea. Sekvenca izolata 27/1 dobijena sekvencionom 16S rDNA analizom se sastoji od 1407 nukleotida, na osnovu čega je ovaj izolat identifikovan kao Kocuria sp. Nakon inkubacije od 86 dana, stepen degradacije početnih koncentracija MTBE-a od 25 i 125 μg/ml iznosio je 55, odnosno 36%. Pri početnoj koncentraciji od 25 μg/ml optička gustina i brojnost bakterija se smanjuju u prvih 15 dana inkubacije, dok je pri početnoj koncentraciji od 125 μg/ml zabeleženo smanjenje optičke gustine i broja bakterija u prvih 30 dana. Nakon ovog perioda, stepen bakterijskog rasta se povećava. U početnim fazama Inkubacije, stepen degradacije MTBE-a nije visok, dok je krajem inkubacionog perioda konstatovan najveći stepen degradacije. Ovi rezultati ukazuju na uspešnu adaptaciju bakterije Kocuria sp. na prisustvo MTBE-a, što opravdava njenu primenu u bioremedijaciji zemljišta i voda kontaminiranih MTBE-om.

Methyl tertiary butyl ether (MTBE) belongs to the group of gasoline oxygenates and persistent environment contaminants, and shows potential for biodegradation in aerobic and anaerobic conditions, through application of pure microbial cultures. Presented research shows that indigenous bacterial isolates 6sy and 24p, selected from oil hydrocarbons-contaminated environments, were capable of utilizing MTBE as sole carbon and energy source. Based on 16S rDNA sequence analysis, bacterial isolates 6sy and 24p were identified as Staphylococcus saprophyticus subsp. saprophyticus and Pseudomonas sp., respectively. The MTBE biodegradation rate was affected by longevity of incubation period and initial MTBE concentration. After 3 weeks of incubation at 25 degrees C in a dark, the removal rates of initial 25 and 125 ppm MTBE concentrations by Staphylococcus saprophyticus 6sy were found to be 97, and 63%, respectively, while efficiency of Pseudomonas sp. in degradation of indicated concentrations was 96, and 40%, respectively. Both bacterial isolates were able to grow in MTBE-containing growth medium. Highest growth rate of bacterial isolates was observed at the end of incubation period. The presented results indicated the potential of these bacterial isolates in bioremediation of MTBE-contaminated environments.

International audience; The degradation of fuel oxygenates [methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME)] by Rhodococcus ruber IFP 2001, Rhodococcus zopfii IFP 2005 and Gordonia sp. IFP 2009 (formerly Mycobacterium sp.) isolated from different environments was compared. Strains IFP 2001, IFP 2005 and IFP 2009 grew on ETBE due in part to the activity of a cytochrome P450, CYP249. All of these strains were able to degrade ETBE to tert-butyl alcohol and are harboring the CYP249 cytochrome P450. They were also able to degrade MTBE and TAME, but ETBE was degraded in all cases most efficiently, with degradation rates measured after growth on ETBE of 2.1, 3.5 and 1.6 mmol ETBE g-1 dry weight h-1 for strains IFP 2001, IFP 2005 and IFP 2009, respectively. The phylogenetic relationships between the different ethR (encoding the regulator) and ethB (encoding the cytochrome P450) genes were determined and showed high identity between different ethB genes (> 99%). Only ETBE was able to induce the expression of ethB in strains IFP 2001 and IFP 2005 as measured by reverse transcriptase quantitative PCR. Our results are a first indication of the possible role played by the ethB gene in the ecology of ETBE degradation

Summarization: The removal of BTEX (benzene, toluene, ethyl-benzene and xylenes) and MTBE (methyl tertiary butyl ether) from aqueous solution by raw (DR) and thermally modified diatomite at 550, 750 and 950 °C (D550, D750 and D950 respectively) was studied. Physical characteristics of both raw and modified diatomite such as specific surface, pore volume distribution, porosity and pHsolution were determined, indicating important structural changes in the modified diatomite, due to exposure to high temperatures. Both adsorption kinetic and isotherm experiments were carried out. The kinetics data proved a closer fit to the pseudo-second order model. Maximum values for the rate constant, k2, were obtained for MTBE and benzene (48.9326 and 18.0996 g mg−1 h−1, respectively) in sample D550. The isotherm data proved to fit the Freundlich model more closely, which produced values of the isotherm constant 1/n higher than one, indicating unfavorable adsorption. The highest adsorption capacity, calculated through the values of the isotherm constant kF, was obtained for MTBE (48.42 mg kg−1 (mg/L)n) in sample D950. Presented on: Journal of Hazardous Materials

The subject of this research was utilization of concentrated solar radiation simulated with a sodium lamp SONT UV100, in lab condition, on removal of wastewater polluted by methyl-tertiary-butyl-ether (MTBE). The effects of titanium dioxide catalyst (commercial: Degussa P-25 (R) and 100% anatase, as well as sol-gel obtained titanium) on degradation of MTBE have been investigated. The processes were performed in slurry-catalyst batch circulating reactor. The photocatalytic degradation with different concentrations of TiO2 Degussa P-250 (R) catalyst: 2.5 g/L, 1 g/L and 0.50 g/L was studied. Our results showed that the MTBE degradation reached 50.80% in only 60 minutes, when 2.5 g/L of that catalyst was used. Also, the concentrated irradiation in combination with TiO2 (100% anatase) and FeCl3 caused high total degradation degree of 58.22%, for only 30 minutes. We synthesized titanium-dioxide, nanopowders doped with LaCl3 center dot 7H(2)O and FeCl3 center dot 6H(2)O, by sol-gel procedure. The highest degradation rate showed La-TiO2, for only 30 minutes and 48.60% of total degradation. Mathematics and Computers in Science and Engineering, 4th IASME/WSEAS International Conference on Water Resources, Hydraulics and Hydrology, Feb 24-26, 2009, Cambridge, England

MTBE was introduced in production in 1970's in order to reduction of air pollution and replacing of toxic compounds from gasoline. After only a few years of its using, it becomes a one of important soil and water contaminant. The aim of this paper was investigation of seed germination and biomass of corn, wheat and alfalfa in presence of different MTBE concentration. The results of investigation showed the inhibitory MTBE effect on plant germination at all used concentration higher from 10 ppm. The decrease in plant biomass was more expressed in maize compared to other two species. It was concluded that MTBE due its mobility, solubility and persistence, had toxic effects on metabolic processes in seeds and changed biomass production in early stage of plant development. . MTBE je uveden u proizvodnju 70-ih godina XX veka u cilju redukcije aerozagađenja i zamene toksičnih komponenti iz benzina. Posle svega nekoliko godina upotrebe, MTBE je definisan kao značajan kontaminant zemljišta i voda. Cilj ovog rada bio je ispitivanje klijavosti semena i biomase kukuruza, pšenice i lucerke u prisustvu različitih koncentracija MTBE-a. Rezultati istraživanja pokazuju da (i) ispitivane biljne vrste različito reaguju na povećane koncentracije MTBE-a, (ii) biljke su klijale samo pri najnižim koncentracijama MTBE-a (10 ppm), (iii) biomasa je kod kukuruza bila drastično smanjena pri koncentraciji od 10 ppm dok je kod ostale dve biljne vrste smanjenje biomase bilo mnogo manje izraženo. Svi ovi rezultati ukazuju da se MTBE, zbog svoje perzistentnosti, mobilnosti i rastvorljivosti u vodi, aktivno uključuje u metabolizam biljaka u ranim fazama porasta. .

In this work we isolated from soil and characterized several bacterial strains capable of either resisting high concentrations of heavy metals (Cd(2+) or Hg(2+) or Pb(2+)) or degrading the common soil and groundwater pollutants MTBE (methyl-tert-butyl ether) or TCE (trichloroethylene). We then used soil microcosms exposed to MTBE (50 mg/l) or TCE (50 mg/l) in the presence of one heavy metal (Cd 10 ppm or Hg 5 ppm or Pb 50 or 100 ppm) and two bacterial isolates at a time, a degrader plus a metal-resistant strain. Some of these two-membered consortia showed degradation efficiencies well higher (49-182% higher) than those expected under the conditions employed, demonstrating the occurrence of a synergetic relationship between the strains used. Our results show the efficacy of the dual augmentation strategy for MTBE and TCE bioremediation in the presence of heavy metals.

Tesis del Departament de Química Analítica de la Universitat de Becelona (UB).-- Fecha de defensa 15-09-2006., [CAT] En els últims anys, s’ha observat una preocupació creixent pels efectes que les emissions de gasos procedents de la gasolina poden provocar tant a nivell ambiental com en la salut de les persones i això s’ha vist reflectit en canvis substancials en la seva composició. La prohibició dels additius plomats, així com la limitació contínua dels compostos aromàtics (sobretot del benzè) han donat lloc a una expansió espectacular arreu del món de l’ús dels additius oxigenats a la gasolina. D’entre aquests additius (principalment èters i alcohols) el més emprat ha estat el metil terciari (tert-) butil èter (MTBE). Però degut a les seves propietats físico-químiques, aquest compost orgànic volàtil (VOC) ha esdevingut un important contaminant de les aigües subterrànies d’arreu del món., La present tesi doctoral ofereix una visió general i actualitzada de la problemàtica ambiental lligada a la utilització del MTBE com additiu de la gasolina, alhora que desenvolupa tècniques analítiques mitjançant un sistema totalment automatitzat de Purga i Trampa (també anomenat Purga i Captura) unit a un Cromatògraf de Gasos acoblat a un Espectròmetre de Masses (P&T-GC/MS) que permeten conèixer quantitativament i amb precisió la presència a nivells traça del MTBE, els seus principals compostos de degradació, altres additius convencionals com són els hidrocarburs aromàtics (benzè, toluè, etilbenzè i xilens, BTEX), així com els seus possibles substituts (etil tert-butil èter, ETBE; tert-amil metil èter, TAME; i diisopropil èter, DIPE) i altres VOCs d’interès (diciclopentadiè, DCPD i tricloretilè, TCE) als diferents compartiments ambientals (diferents matrius aquoses i sòls), posant un especial èmfasi en l’anàlisi de les aigües subterrànies, més susceptibles d’una elevada contaminació i la qualitat de les quals és de vital importància ja que actuen com a magatzems d’aigua dolça pel consum humà., A més, en tant que l’avaluació de la biodegradació in situ del MTBE en llocs contaminats requereix de molt més que simples balanços de massa i la mera presència del TBA no és suficient com per provar-ne la relació causa-efecte. S’han realitzat estudis de degradació del MTBE i ETBE mitjançant la utilització de diferents soques bacterianes amb capacitat per alimentar-se d’aquests additius de la gasolina en condicions aeròbiques (microcosmos) per tal d’analitzar-ne els isòtops estables tant del carboni com l’hidrogen (CSIA) obtenint diferents factors de fraccionament isotòpic. Els resultats obtinguts posen en dubte l’existència d’un únic mecanisme de degradació metabòlica en condicions d’aerobiosis (com es creia fins ara) i dificulten la seva aplicació com a indicadors quantitatius dels processos de biodegradació que tenen llocs als llocs contaminats si no es realitzen altre tipus de mesures addicionals., [EN] In the latest years, the combustion emissions from the vehicles have aroused concern about their potential adverse effects on the environment and the human health. This fact has resulted in a substantial change of the gasoline composition. The ban of the lead additives, as well as the increasing limitation for the use of aromatic hydrocarbons (especially benzene) contributed to a great expansion of the fuel oxygenates worldwide. Among these additives (mainly ethers and alcohols), methyl tertiary (-tert) butyl ether (MTBE) is by far the most commonly used octane enhancer. However, as a result of its physico-chemical properties, MTBE has become one of the most frequently detected volatile organic compounds (VOCs) in groundwater around the world., The purpose of the present thesis is to provide an updated overview of the MTBE environmental problem, meanwhile an analytical technique, a fully automated purge and trap coupled to gas chromatography – mass spectrometry (P&T-GC/MS) method has been developed and permitted the simultaneous quantitative determination of MTBE, its degradation products, other fuel additives such as the aromatic hydrocarbons or MTBE potential substitutes in different environmental compartments (liquid or solid matrices) at trace levels (sub-ppb). The thesis has been focused mainly in the analysis of drinking water reservoirs such as contaminated groundwater tables around Europe., However, an inconclusive MTBE mass balance or the mere presence of its intermediate tert-butyl alcohol (TBA) has been found inappropriate for providing evidence for natural attenuation of MTBE in contaminated sites. So, as compound-specific stable isotope analysis (CSIA) has become a promising tool for evaluating in situ degradation, the carbon and hydrogen isotope enrichment factors (εC, εH) of MTBE and ethyl tert-butyl ether (ETBE) upon aerobic degradation were studied with different bacterial isolates. This work demonstrated that highly variable isotope fractionation factors are found under aerobic conditions, which may indicate the use of different mechanisms for degrading fuel oxygenates by different strains. This makes the selection of appropriate isotope enrichment factors for quantitative work difficult and can lead to strong variable fractionation in mixed cultures depending on the dominance of organism actually growing best in the field site.

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2002, Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2002, Si/Al oranları farklı H-ZSM-5 katalizörleri, metanol ile saf izobütilen arasındaki MTBE reaksiyonunda taranmış, seçilen katalizörler katı hal NMR, FTIR yöntemleri, NH3-TPD ve Ar adsorpsiyonu deneyleriyle karakterize edilmiştir. Katalizörlerden birine MTBE sentez aktivitesini artırması beklenen su buharı modifikasyonları uygulanmış, maksimum katalitik aktiviteyi sağlamak üzere su buharı modifikasyon yöntemi optimize edilmiştir. Maksimum aktivitenin elde edildiği örnek aynı yöntemler ile karakterize edilmiştir. Orijinal katalizör serisinde maksimum MTBE sentez aktivitesini veren örnek (Si/Al=40) Broensted asit merkezleri çok fazla olmayan, ancak iskelet dışı Al yapıları fazlaca olan bir örnektir. NH3-TPD incelemesi, yapısında farklı kuvvetlerde beş tip asit merkez olduğunu ve bu tiplerden birinin, NH3 desorpsiyonunun aktivasyon enerjisi 90 kJ/mol den büyük olan, kuvvetli asit merkezlere karşı geldiğini göstermiştir. Adsorpsiyon deneyleriyle, bu örneğin dış yüzey alanının da diğer örneklere kıyasla daha yüksek olduğu belirlenmiştir. Su buharı modifikasyon deneylerinde, işlem parametrelerinin her birindeki artışa bağlı olarak, MTBE sentez aktivitesinin önce arttığı, bir maksimumdan geçtikten sonra azaldığı görülmüştür. Aktivitesi maksimize edilmiş örnek ile kendisinin üretildiği H-ZSM-5 örneği kıyaslandığında aktivitenin 2.75 kat arttığı tespit edilmiştir. En yüksek aktiviteye sahip olan modifiye örnek için elde edilen karakterizasyon sonuçlarından, bu örneğin yapısında, Si/Al oranı 40 olan örnektekinden daha fazla sayıda iskelet dışı aluminyum yapıları oluşturulduğu, daha fazla kuvvetli asit merkez yaratıldığı gösterilmiştir. Aktivitedeki artış, iskelet dışı ve iskeletteki aluminyum atomlarının optimum miktarlarda olmasına ve dış yüzey alanının artırılmasına bağlanmıştır. Si/Al=40 olan H-ZSM-5 ve modifiye örnek ile kinetik deneyler yapılmış, reaksiyon hızının reaktan konsantrasyonlarına bağımlılığı incelenmiş, LHHW yaklaşımı ile verileri en iyi açıklayan reaksiyon mekanizması ve hız ifadesi çıkarılmıştır, A series of H-ZSM-5 catalysts with different Si/Al ratios were screened for the gas-phase MTBE synthesis reaction between methanol and isobutylene and a detailed characterisation was applied to the selected catalyst samples by the application of solid state NMR, FTIR, NH3-TPD and Ar adsorption experiments. Steam modifications were applied to one of the catalysts. Modification parameters were optimized to obtain the maximum catalytic activity. Catalyst sample with the maximum activity was characterized using the same methods. The sample (Si/Al=40) that showed the maximum MTBE synthesis activity among the original H-ZSM-5 samples is observed to be a sample in which the concentration of Broensted sites is not very high but the concentration of the extralattice Al species is quite high. The NH3-TPD experiments showed that this sample had five types of acid sites whose strengths are different and, one of these types corresponding to strong sites having high activation energy of NH3 desorption calculated to be greater than 90 kJ/mole. Adsorption experiments showed that this sample has the highest external surface area where compared to the other samples. As a result of the hydrothermal modifications, the activity increased parallel to the increase in the values of the modification parameters, passed through a maximum, then decreased. When the sample whose activity was maximized is compared with its parent sample, it is observed that the activity was increased 2.75 times. From the characterization results of the steam modified sample, it is seen that this sample has more nonframework aluminum species and stronger acid sites were created in this sample than the sample with the Si/Al=40. The increase in activity is related to the optimum amounts of the lattice aluminum and extralattice aluminum species and the presence of a high external surface area. Kinetic experiments were conducted on H-ZSM-5 with Si/Al=40 and the modified sample, the dependence of the reaction rate on reactant concentrations was studied, the reaction mechanism and the rate expression which represent the experimental data best were determined in accordance with the LHHW approach., Doktora, PhD

In this study, the biodegradation potential of MTBE in uncontaminated and previously contaminated aquifer sediments under aerobic conditions was investigated. Laboratory microcosms were constructed using aquifer samples collected from three different areas of a shallow gasoline-contaminated aquifer in eastern Fairfax Co., Va in the Atlantic Coastal Plain province. Uncontaminated aquifer samples were collected upgradient of the plume, and contaminated aquifer samples were collected in the source area and in an area downgradient of the source. Biodegradation of MTBE was observed in microcosms that contained previously contaminated aquifer sediments. More complete degradation was observed in aquifer sediments containing a low level of petroleum contamination than in heavily contaminated aquifer sediments. Biodegradation of MTBE appeared to be limited by a lack of oxygen in heavily contaminated soils. When degradation was discernible it appeared to follow a first order pattern with a rate constant (l) of between 0.037 and 0.066 d-1, following a lag period of 20 to 40 days. In microcosms containing lightly contaminated aquifer material, MTBE was respiked during active metabolism, and degradation occurred with no lag or acclimation period. Results indicated that little or no degradation occurred in the microcosms containing uncontaminated soil. The results of this research suggest that the availability and level of petroleum hydrocarbon compounds influence indigenous microorganisms capable of degrading MTBE. Master of Science

"nBackground: Methyl tert-butyl ether (MTBE) has been commercially used as an octane enhancer to replace tetraethyl lead in gasoline since 1979. The high mobility, water solubility, and resistance to natural attenuation associated with MTBE may re­sult in contamination of ground and surface waters. In this investigation the degradation of aqueous MTBE at relatively high concentrations was studied by UV-vis/TiO2/O2 photocatalytic process. The effect of important operational parameters such as pH, oxygen flow, catalyst loading, and irradiation time were also studied."nMethods:Concentration of MTBE and intermediates such as tert-butyl formate (TBF) and tert-butyl alcohol (TBA) were meas­ured using a gas chromatograph equipped with flam ionization detector and combined with headspace sampler."nResults: The time required for complete degradation increased from 15 to 150 min, when the initial concentration was in­creased from 10 to 500 mg/L. The first order rate constant for degradation of MTBE from the hydroxyl radical was esti­mated to be 0.266 to 0.033 min-1 as the concentration increased from 10 to 500 mg/L. Study on the overall mineralization moni­tored by total organic carbon (TOC) analysis showed that in the initial concentration of 100 mg/L MTBE, complete min­eralization was obtained after 110 min under UV-vis/TiO2/O2 photocatalytic process."nConclusion: The data presented in this paper clearly indicate that UV/TiO2/O2 advanced oxidation process provides an effi­cient treatment alternative for the remediation of MTBE contaminated water. &nbsp