A Kinetic Model for the Aqueous Degradation of MTBE by Fe0/H2O2

2007 ◽  
Vol 32 (3) ◽  
pp. 131-151 ◽  
Author(s):  
Nada M. Al-Ananzeha ◽  
John A. Bergendahlb ◽  
Robert W. Thompsona

Methyl tertiary-butyl ether (MTBE) is a possible human carcinogen that has been used as a gasoline oxygenate at concentrations of up to 15% by volume for about 45 years in the US. However, its high water solubility has exacerbated spills at gasoline stations, sometimes resulting in local groundwater MTBE contamination levels of over 100 mg/L. Advanced oxidation using Fe0 and H2O2 is a promising technique for mineralizing organic contaminants, but current understanding of the remediation chemistry needs to be improved to facilitate design of subsurface or engineered systems. A kinetic model for the degradation of MTBE in batch systems applying zero-valent iron (Fe0) andhydrogen peroxide (H2O2) oxidation in aqueous solution was developed. The model includes: H2O2 and water chemistry, iron speciation, and MTBE oxidation reactions. H2O2/water and MTBE degradation equilibrium and reaction rate parameters were taken from the literature. Reaction rate and equilibrium parameters for iron speciation were taken from the literature, or from our prior work. The rate constant for the dissolution of Fe0 was found from this work. The model was compared to experimental data from the literature for MTBE degradation using Fe0/H2O2

2006 ◽  
Vol 3 (1) ◽  
pp. 40 ◽  
Author(s):  
Nada Al Ananzeh ◽  
John A. Bergendahl ◽  
Robert W. Thompson

Environmental Context.Since the early 1990s, methyl tert-butyl ether (MTBE), a possible human carcinogen, has been used as a gasoline oxygenate at concentrations of up to 15% by volume; however, a fraction of the MTBE produced has inevitably been released to the environment. And, spills at gasoline service stations have resulted in local groundwater contamination levels of MTBE over 100 mg L−1, because of its very high water solubility. Advanced oxidation is a common technique for mineralizing organic contaminants, but the reaction chemistry needs to be better understood to facilitate design of remediation systems. Abstract.A kinetic model for the degradation of methyl tert-butyl ether (MTBE) in batch reactors with Fenton’s oxidation (Fe2+/ H2O2) in aqueous solutions was developed. This kinetic model consists of equations accounting for (1) hydrogen peroxide chemistry in aqueous solution, (2) iron speciation, and (3) MTBE oxidation. The mechanisms of MTBE degradation, and the resultant pathways for the formation and degradation of the byproducts, were proposed on the basis of previous studies. A set of stiff nonlinear ordinary differential equations that describe the rate of formation of each species in this batch system was solved using Matlab (R13) software. The kinetic model was validated with published experimental data. The degradation of MTBE by Fenton’s oxidation is predicted well by the model, as are the formation and degradation of byproducts, especially methyl acetate (MA) and tert-butyl alcohol (TBA). Finally, a sensitivity analysis based on calculating the sum of the squares of the residuals (SSR) after making a perturbation of one rate constant at a time was applied to discern the effect of each reaction on MTBE disappearance.


Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 578
Author(s):  
Worawit Intrchom ◽  
Sagar Roy ◽  
Somenath Mitra

Methyl tert-butyl ether (MTBE) is a widely used gasoline additive that has high water solubility, and is difficult to separate from contaminated ground and surface waters. We present the development in functionalized carbon nanotube-immobilized membranes (CNIM-f) and graphene oxide-immobilized membranes (GOIM) for enhanced separation of MTBE via sweep gas membrane distillation (SGMD). Both types of modified membranes demonstrated high performance in MTBE removal from its aqueous mixture. Among the membranes studied, CNIM-f provided the best performance in terms of flux, removal efficiency, mass transfer coefficients and overall selectivity. The immobilization f-CNTs and GO altered the surface characteristics of the membrane and enhanced partition coefficients, and thus assisted MTBE transport across the membrane. The MTBE flux reached as high as 1.4 kg/m2 h with f-CNTs, which was 22% higher than that of the unmodified PTFE membrane. The maximum MTBE removal using CNIM-f reached 56% at 0.5 wt % of the MTBE in water, and at a temperature of 30 °C. With selectivity as high as 60, MTBE recovery from contaminated water is very viable using these nanocarbon-immobilized membranes.


2012 ◽  
Vol 599 ◽  
pp. 412-417 ◽  
Author(s):  
Yue Hua Li ◽  
Yu Long Liu ◽  
Hao Deng ◽  
Suo Lei Zhang

The modified oil sludge (MOS) was a novel sorbent in groundwater remediation, and it has a carbon content of 37-50% and a huge adsorption capacity after its pyrolytic treatment. This study highlights the adsorption potential of MOS to remove organic contaminants in groundwater. Batch-type experiments about the adsorption and desorption characteristics of MOS to MTBE, TCE and benzene were conducted. Results showed that the adsorption removal rate of TCE and benzene were up to 99%, and was lower for MTBE (88-93%) due to its high water solubility, but the maximum adsorption capacity of MOS to MTBE was still larger (14.3-33.3 mg/g). The desorption quantities of TCE and benzene was 0.4% and 1%, respectively; but was larger for MTBE (10%), and similar trend was also found for the desorption hysteresis coefficient.


2013 ◽  
Vol 13 (3) ◽  
pp. 782-789 ◽  
Author(s):  
Bassam Tawabini ◽  
Amjad Khalil ◽  
Basim Abussaud

This study demonstrates the reduction of Escherichia coli bacteria from contaminated water when the water is treated with advanced oxidation processes utilising the following combinations: hydrogen peroxide (H2O2) and ozone (O3), ultraviolet light (UV) and hydrogen peroxide (H2O2), and ultraviolet light (UV) and ozone (O3). Approximately 1 × 108cell/mL of E. coli were spiked into water samples contaminated with 500 ppb of methyl tertiary butyl ether (MTBE) and benzene. Water samples were then treated in a bench-scale photoreactor using 15 W low pressure (LP) and 150 W medium pressure (MP) UV lamps. Hydrogen peroxide at 20, 50 and 100 ppm and ozone at 1, 2 and 5 ppm were used along with the UV irradiation to generate the hydroxyl radicals (.OH) needed to degrade organic contaminants such as MTBE and benzene and most likely destroy bacteria. The results of the study showed that, under the study conditions, no effect of benzene or MTBE was observed on the inactivation rate of the bacteria. Moreover, results showed that the combined effect of the LP 15 W UV lamp with 2 ppm O3 or with 50 ppm H2O2 showed the highest inactivation rate of bacteria within 5 min. The H2O2/O3 process showed high disinfection capability at high dosages of peroxide (50 ppm) and O3 (2 and 5 ppm).


2017 ◽  
pp. 91-95
Author(s):  
E. I. Grushova ◽  
A. .. Al Razuqi ◽  
E. S. Chaiko ◽  
O. A. Miloserdova

IR spectroscopy investigated structural and group composition of base mineral oils isolated from the vacuum distillate by selective purification of N-methylpyrrolidone and the low temperature dewaxing in the presence of a solvent. The role of the latter was carried out by the systems acetone - toluene, acetone - methyl tertiary butyl ether, methyl ethyl ketone - toluene, acetone - toluene - modifying additive. It was shown that the chemical composition of the group of base oils and slack waxes is defined as the nature of the solvent to the dewaxing, and oils sequence of purification steps.


2002 ◽  
Vol 125 (1) ◽  
pp. 344-350 ◽  
Author(s):  
S. G. Poulopoulos ◽  
C. J. Philippopoulos

In the present work, the effect of adding ethanol or methyl tertiary butyl ether (MTBE) to gasoline on the regulated and unregulated emissions from an internal combustion engine with a typical three-way catalyst was studied. The addition of ethanol to fuel (10% w/w) increased both the research octane number and the Reid vapor pressure of the fuel, whereas adding 11% w/w MTBE caused an increase only in the research octane number of the fuel. When the fuel contained MTBE, less hydrocarbons, carbon monoxide, and acetaldehyde were emitted in the tailpipe. The increased emissions of acetaldehyde and ethanol were the main disadvantages of using ethanol.


1989 ◽  
Vol 67 (5) ◽  
pp. 857-861 ◽  
Author(s):  
Shin-Ichi Miyamoto ◽  
Tetsuo Sakka ◽  
Matae Iwasaki

The reaction rate of hydrogen isotope exchange between D2 and H2O catalyzed by platinum plate is studied. The exchange reaction is described with the kinetic model which is the modification of that for the exchange reaction catalyzed by alumina-supported platinum catalyst. For the comparison of experimental results with this model relative amount of the number of sites for hydrogen adsorption was estimated from the initial rate of hydrogen isotope exchange between H2 and D2 on the same surface. The results show that the kinetic model is applicable for the plate catalyst if the number of the sites for hydrogen absorption, which is very sensitive to the surface state of the catalyst, was estimated not from the macroscopic surface area but from our scheme. Keywords: hydrogen isotope exchange reaction, platinum plate as catalyst.


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