含MTBE废水处理研究进展

主要介绍了含MTBE废水处理的工艺进展以及一些新方法、技术在实验以及生产实践中的应用 ,如氧化、气提、吸收、降解和自然衰减等 ,同时对各种方法的优缺点进行了评述 ,对未来的工艺进步做了展望     

化固定化Methylibium petroleiphilum PM1细胞降解MTBE及动力学特性分析

采用海藻酸钙包埋固定化高效降解菌Methylobium petroleiphilum PM1降解水相中的甲基叔丁基醚(MTBE),考察了不同强化方法对凝胶颗粒机械强度和降解活性的影响.响应面结果表明,交联剂和培养基中Ca2+浓度分别为0.2 mol·L-1和1.38mmol·L-1,化学交联剂聚乙烯亚胺(PEI)浓度为...     

A ban on one is a boon for the other: Strict gasoline content rules and implicit ethanol blending mandates

Ethanol and methyl-tertiary butyl ether (MTBE) were close substitutes in the gasoline additives market until MTBE was banned due to the concerns about groundwater contamination, leading to a sudden and dramatic substitution toward ethanol as an alternative oxygenate and octane-booster. We use variation in the timing of MTBE bans across states to identify their effects on gasoline prices. We find that state bans increased reformulated gasoline prices by 3–6 cents in non-Midwestern states for which the bans were binding, with larger impacts during times of high ethanol prices relative to MTBE and crude oil. We find qualitatively similar, yet smaller effects for conventional gasoline. We argue on the basis of a simple conceptual model and supporting empirical evidence that these bans functioned as implicit ethanol blending mandates in areas that were previously using MTBE to comply with strict environmental constraints. Overall, our results are consistent with the theoretical prediction that mandating a minimum market share for a more costly alternative fuel—either directly, or implicitly through a ban on the preferred conventional fuel—will inevitably increase fuel prices in a competitive market.     

汽油添加剂MTBE的最新研究及替代品

随着国家对环境保护的日趋重视，目前我国大部分城市禁止销售加铅汽油，使用TMBE作为汽油添加剂，可以提高汽油含氧量减少汽车尾气中的污染物，但由于其本身的性质，对环境可能带来的一些问题，也正被人们所重视。     

Distributions of personal VOC exposures: a population-based analysis

Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999-2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.     

Paradoxical ozone associations could be due to methyl nitrite from combustion of methyl ethers or esters in engine fuels

We review studies of the effects of low ambient ozone concentrations on morbidity that found a negative coefficient for ozone concentration. We call this a Paradoxical Ozone Association (POA). All studies were in regions with methyl ether in gasoline. All but one study carefully controlled for the effects of other criterion pollutants, so the phenomenon cannot be attributed to them. One was in southern California in mid-summer when ozone levels are highest. Because ozone is created by sunlight, the most plausible explanation for a POA would be an ambient pollutant that is rapidly destroyed by sunlight, such as methyl nitrite (MN). A previously published model of engine exhaust chemistry suggested methyl ether in the fuel will create MN in the exhaust. MN is known to be highly toxic, and closely related alkyl nitrites are known to induce respiratory sensitivity in humans. Support for the interpretation comes from many studies, including three linking asthma symptoms to methyl tertiary butyl ether (MTBE) and the observation that a POA has not been seen in regions without ether in gasoline. We also note that studies in southern California show a historical trend from more significant to less significant ozone-health associations. The timing of those changes is consistent with the known timing of the introduction of gasoline oxygenated with MTBE in that region.     

UV/Fenton氧化降解水溶液中甲基叔丁基醚的试验研究

采用UV／Fenton技术对污染水体中的甲基叔丁基醚（MTBE）进行了氧化降解试验。结果表明，在室温条件下，当H2O2为10mmol／L，FC＋为2mmol／L，pH为2．4时，起始摩尔浓度为1mmol／L的MTBE在30min内可去除99％；结果还显示了MTBE的降解分两个阶段，第一阶段是在UV／Fe^2＋／H2O2下的快速降解，第二阶段由于Fe^2＋的大量消耗而降解相对较慢。     

Fuel derived pollutants and boating activity patterns in the Sea of Galilee

MTBE (Methyl tert-Butyl Ether) is a fuel additive that replaced lead as an antiknock compound in internal combustion motors. Few years after its introduction, detectable levels of MTBE were found in various water bodies. MTBE has a very low taste and odor threshold and is a potential carcinogen. Another group of fuel derived toxic compounds that has been detected in water bodies is BTEX (Benzene, Toluene, Ethylbenzene and Xylene). Boating activity and allochthonous contributions from watersheds are the major sources of fuel derived pollutants in lakes. Their concentrations in lakes thus vary as a function of boating activity intensity, lake surface area and depth, weather and wind regime, land-use in the watershed, etc. The Sea of Galilee (Lake Kinneret) is the only recreational lake in Israel and an important freshwater source. In the current study, a sampling campaign was conducted in order to quantify MTBE and BTEX concentrations in Lake Kinneret, its marinas and its main contributing streams. In addition, a boating-use survey was performed in order to estimate MTBE and BTEX contribution of recreational boating. The sampling campaign revealed that, as expected, MTBE concentrations were higher than BTEX, and that near shore (i.e., marina) concentrations were higher than in-lake concentrations. Despite the clear contribution from boating, high MTBE concentrations were found following a major inflow event in winter, indicating the importance of the allochthonous contribution. The contribution from boating during summer, as measured indirectly by in-lake concentrations, is likely underestimated due to enhanced MTBE volatilization due to strong winds and high temperatures. May–September was found to be the main recreational boating season, with continued boating year round. On average, a single boat is active 23 d/y, with 84% of the watercrafts being active only during weekends and holidays. The survey further indicated that boats stay in the lake for 4.5 h on average, which conforms to the unique winds regime that limits afternoon activity due to high winds, and have an average fuel consumption of 14 L/h. The annual load of MTBE and BTEX from recreational boating in Lake Kinneret was estimated at 4430 and 6220 kg/y respectively.     

Laboratory evidence of MTBE biodegradation in Borden aquifer material

Mainly due to intrinsic biodegradation, monitored natural attenuation can be an effective and inexpensive remediation strategy at petroleum release sites. However, gasoline additives such as methyl tert-butyl ether (MTBE) can jeopardize this strategy because these compounds often degrade, if at all, at a slower rate than the collectively benzene, toluene, ethylbenzene and the xylene (BTEX) compounds. Investigation of whether a compound degrades under certain conditions, and at what rate, is therefore important to the assessment of the intrinsic remediation potential of aquifers. A natural gradient experiment with dissolved MTBE-containing gasoline in the shallow, aerobic sand aquifer at Canadian Forces Base (CFB) Borden (Ontario, Canada) from 1988 to 1996 suggested that biodegradation was the main cause of attenuation for MTBE within the aquifer. This laboratory study demonstrates biologically catalyzed MTBE degradation in Borden aquifer-like environments, and so supports the idea that attenuation due to biodegradation may have occurred in the natural gradient experiment. In an experiment with batch microcosms of aquifer material, three of the microcosms ultimately degraded MTBE to below detection, although this required more than 189 days (or >300 days in one case). Failure to detect the daughter product tert-butyl alcohol (TBA) in the field and the batch experiments could be because TBA was more readily degradable than MTBE under Borden conditions.     

Photocatalytic degradation of aqueous methyl-tert-butyl-ether (MTBE) in a supported-catalyst reactor

Contamination of groundwater by methyl-tert-butyl ether (MTBE) poses increasing problems to water companies. Here we demonstrate the feasibility of using a cylindrical, supported-catalyst reactor for photocatalytic degradation of MTBE in water. It was shown that photocatalytic degradation of MTBE follows pseudo first-order kinetics. The maximum reaction rate constant observed was 0.47 hr^–1. The reaction rate increases linearly with increasing light intensity. It was also found that the reaction rate is linearly proportional to the ratio of catalyst surface area to volume of reactor. Complete degradation of MTBE was reached with an excess supply of oxygen.