Degradation Of MTBE By Bifunction Aluminum & Isolation Of Bacterial Cultures That Degrade MTBE

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.