二-甲基异莰醇(2-MIB)是一种由蓝绿藻以及放线菌等微生物产生,具有桥环结构的饱和叔醇,在水中具有令人厌恶的土霉味,常规水处理工艺难以对其氧化降解.利用大气压强电离放电生成羟基自由基(·OH),对2-MIB 进行氧化降解,确定了其氧化剂剂量效应、时间效应关系,并利用GC-MS对2-MIB氧化降解过程中间产物的分析,推断其氧化降解机制.结果表明:对初始浓度为150,300ng/L的2-MIB,分别投加总氧化剂TRO 1.8,2.3mg/L,接触反应6s去除率分别为96%和97.6%,处理后残余浓度低于10ng/L (低于人类嗅阈值).在2-MIB水样中加入?OH淬灭剂叔丁醇(TBA)后,2-MIB的去除效果明显降低,证明氧化降解2-MIB的主要为?OH.另外通过对氧化降解过程中间产物分析表明,?OH 能破坏2-MIB的桥环结构,并最终矿化生成CO2和H2O.%2-methylisoborneol (2-MIB) produced by cyanobacteria and actinomycetes is a saturated bicyclic-tertiary alcohol, which can cause earthy/musty taste and odor in surface water. Moreover, 2-MIB is usually difficult to be decomposed and removed by conventional water treatment process. In this paper, hydroxyl radical (?OH) generated by a strong ionization discharge process at atmosphere pressure was used to degrade 2-MIB in water, of which the removal efficiency including dose effects and contact reaction time were investigated. The intermediate products formed in ?OH treatment process were analyzed by GC-MS, and the oxidative degradation mechanism of 2-MIB by ?OH was discussed. Results show that the removal rate for 2-MIB with initial concentration of 150and 300ng/L could reach 96% and 97.6% within 6.0s, while the total reactive oxidant (TRO) dose were 1.8and 2.3mg/L, respectively. After ?OH treatment, the concentration of 2-MIB in water was lower than 10ng/L (lower than the human olfactory threshold). The degradation effects of 2-MIB were obviously reduced by the ?OH scavengers tertiary butyl alcohol (TBA), indicating that ?OH should be the main oxidant for 2-MIB oxidative degradation. By analyzing the intermediates produced in the oxidative degradation process, it was found that the bridge ring structures of 2-MIB could be destroyed by ?OH and finally mineralized to CO2 and H2O.
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