【作者】 陈艳；

【导师】 胡勤海；

【作者基本信息】 浙江大学 ， 环境工程， 2006， 硕士

【摘要】 甲基叔丁基醚（MTBE）是使用最广泛的一种汽油添加剂,由于其独特的物理化学性质,易污染水体并持久难降解,对环境及人体均构成了潜在的威胁,其污染修复一直是人们所面临的难题。本文从两方面进行MTBE的降解实验研究:一方面采用物化方法,对双功能铝降解MTBE进行了研究;另一方面对微生物进行培养驯化,分离MTBE降解菌,并试验所得菌株降解MTBE的能力。 （1）双功能铝降解MTBE的实验结果表明:双功能铝能活化分子氧降解MTBE。在各初始浓度条件下,经过24h的反应,MTBE的去除率均可达到92%以上。MTBE初始浓度越大,表现在反应中的降解速率越大,经24h的反应百分比去除率也越高。酸性的环境条件（pH<3.5）比较适宜双功能铝对MTBE的降解,最佳pH约在2.0左右。实验中检测到的中间产物有丙酮、TBA、乙酸甲酯和TBF。假设的降解机制为:硫酸盐作为电子载体,把电子从金属铝传递给分子氧;金属铝作为电子源,能为还原性硫酸盐提供电子,从而形成了一个活跃地带。反应动力学拟合结果显示,反应对MTBE来说,为一级动力学反应。由分析结果可以得出,速率常数k=0.1190h^-1,常温下双功能铝与MTBE反应的半衰期约为5.825h。 （2）本试验成功的从土壤中驯化分离得到两株能降解MTBE的纯培养,分别为BC-1和BC-2。它们均能在好氧、一定MTBE浓度条件下,利用MTBE作为唯一的基质碳源较好地生长。培养6d后,两种纯培养均能降解溶液中绝大部分的MTBE（浓度在5～81mg/L之间）,降解率在99%以上。BC-1和BC-2对MTBE都有较为显著的降解能力,BC-2的降解速度明显快于BC-1,短期（<4d）降解效果也好于BC-1。实验结果显示,MTBE在高浓度时成为抑制剂,并能导致菌体细胞的死亡,相比较BC-2对MTBE的耐受性比BC-1要好。实验中检测到的MTBE降解产物有TBA、丙酮、TBF等,这些中间产物也能为微生物所降解。两种菌株为将来的进一步研究生物反应器及环境中MTBE污染的生物修复提供很好的菌源。更多还原

【Abstract】 Methyl tert-Butyl Ether (MTBE), as a widely used gasoline additive as well as a kind of persistent and refractory pollutant, has been used since 1979 to reduce the level of carbon monoxide and volatile organic compounds from the emissions of motor vehicles. For rapid increase in the use of MTBE, it will pose a potential pollution threat to surface water and groundwater due to the increasing quantity of MTBE entering into the environment and water through various ways. Degradation of MTBE by bifunctional aluminum and isolation of bacterial cultures that degrade MTBE are researched.(1) Bifunctional aluminum is prepared by sulfating aluminum metal with sulfuric acid. The use of bifunctional aluminum to degrade MTBE has been examined using batch system. At all initial MTBE concentrations, >92% of MTBE was degrade by bifunctional aluminum within 24h. The 24h % removal increased with initial MTBE concentrations increased. Acidic condition (pH <3.5) was benefit for MTBE degradation, the most benefit pH value was ~2.0.Primary degradation products were ferf-butyl alchol (TBA) , tert-butyl formate (TBF), acetone, and methyl acetate. A postulated mechanism of the degradation is that sulfate acts as an electron carrier which transfers electrons from aluminum metal to dioxygen. Aluminum metal serves as the electron source for the reduction of oxidized sulfur species, thus creating an active site.The rate of MTBE degradation exhibited first-order behavior, and the rate of MTBE degradation was -0.1190 h-1, the half-life of reaction was ~5.825h.(2) Two pure bacterial cultures degrading MTBE were isolated from soil under an old Gingko tree. They are BC-1 and BC-2. Both of the cultures can use MTBE as the sole carbon source to grown under aerobic condition in some concentration extension. After 6 days of incubation at 25 ℃, two cultures both can degrade most MTBE (concentrations range 5-81 mg/L) in the aqueoussolution. The rate of the biodegradation by BC-2 is obviously faster than BC-1, as well as the effect of short-term (< 4d) degradation. Result of experiments show that MTBE at high concentration will be an inhibitor and lead the death of cells. The MTBE endurance of BC-1 is better than BC-2. Degradation products that we have detected were TBA, TBF, acetone. These medium products can also degraded by the two bacterial cultures discussed above.更多还原