Methyl tert-butyl ether (MtBE) in deep wells of the Patiño Aquifer, Paraguay: A preliminary characterization

Effects of Unconventional Additives in Gasoline on the Performance of a Vehicle

In order to meet stricter emissions regulations and fuel consumption regulations, the upgrading of fuel quality has become one of the most important trends in the development of internal combustion engines. In this article, 89 # gasoline (G89) that is available on the Chinese market was selected as the base fuel, and five unconventional additives, ethyl tert-butyl ether (ETBE), N-Methylaniline, sec-butyl acetate, p-methylphenol and isobutanol, were added to the base fuel and named as G89-1, G89-2, G89-3, G89-4 and G89-5, respectively. The effects of these unconventional additives on a PFI vehicle were investigated. The test was carried out on a chassis dynamometer and the NEDC cycle was adopted to simulate driving conditions. The results show that, in terms of fuel consumption, G89-3 showed the best performance for decreasing fuel consumption. In terms of gaseous emissions, G89-4 decreased all four gaseous emissions, CO2, CO, THC and NOx, to a greater extent, which indicates that blending p-methylphenol into gasoline has a better potential for the vehicle to achieve cleaner emissions. In terms of acceleration performance, the five additives all shortened the acceleration time. The effects of the different additives on shortening acceleration time are basically consistent with the RON of the fuel.

Removal and Recovery of Methyl Tertiary Butyl Ether (MTBE) from Water Using Carbon Nanotube and Graphene Oxide Immobilized Membranes

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.

VUV/Fe(II)/H2O2 as a novel integrated process for advanced oxidation of methyl tert-butyl ether (MTBE) in water at neutral pH: Process intensification and mechanistic aspects

Vacuum UV (VUV) technologies have recently attracted high interest due to their high efficacy in generating reactive oxygen species (ROS). To date, no systematic study of the modes of action of the integrated VUV/Fe(II)/H₂O₂ process against contaminants elimination exists; the present study reports the oxidation of MTBE in a new light-assisted Fenton-process, by employing either narrowband UVC (254 nm) or VUV (185 and 254 nm) irradiation, in a comparative evaluation. The processes under investigation were the UVC- or VUV/Fe(II)/H₂O₂ sensitized ones and their constituents, i.e. Fe(II)/H₂O₂, VUV, VUV/Fe(II), VUV/H₂O₂, VUV/Fe(II)/H₂O₂, as well as the UVC, UVC/H₂O₂ and UVC/Fe(II)/H₂O₂. We scrutinize the operational parameters of the VUV-assisted process, its enhancements and synergies, comparison with the UVC-based ones, as well as their inflicted pathways towards MTBE degradation. Complete degradation and 87.8% mineralization of 50 mg/L MTBE was achieved in the VUV/Fe(II)/H₂O₂ process (0.9 mM Fe(II) and 3 mM H₂O₂), at near-neutral pH (reaction times: ∼30 and 60 min, respectively). Irradiation with VUV light was found to act synergistically and in high kinetic rates enhancement compared to the UVC source, sensitizing the Fenton process for effective oxidation of MTBE in the aqueous solution. A scavenger study and degradation by-products investigation has been performed, leading to a mechanistic pathway proposition, elucidating MTBE degradation. The VUV/Fe(II)/H₂O₂ process demonstrated potential applicability in the field since it could efficiently treat (100% degradation and 86.4% mineralization) groundwater spiked with MTBE, operated either under batch or continuous-flow mode. The findings clearly indicates the VUV-assisted Fenton as an emerging and viable technology for field application to treat the MTBE-contaminated effluents or waters.