三种不同氧化工艺条件下对乙酰氨基酚的降解过程与产物毒性变化研究

Degradation of acetaminophen and toxicity evaluation of the degradation products under three oxidation processes

作为一种典型的药物,对乙酰氨基酚(acetaminophen,ACE)由于其广泛存在和潜在毒性引起重要关注.本研究比较了氯化、紫外/过氧化氢(UV/H2O2)和紫外/氯(UV/Cl)三种工艺对ACE的降解情况.结果表明,3种工艺中,UV/Cl和UV/H2O2工艺均能完全降解ACE,其中UV/Cl工艺的降解速率更快. UV/H2O2和UV/Cl工艺降解能用准一级动力学模型很好地拟合,它们的反应动力学常数(kobs,ACE)分别为0.1343 min-1和0.0657 min-1(293K,p H=7).通过p H实验发现,酸性条件下UV/Cl工艺效果更好,而p H对UV/H2O2工艺没有显著影响.相比而言,ACE的矿化比降解困难许多,在60 min后其矿化率最高仅为5.60%(UV/Cl工艺).在UV/Cl工艺降解过程中,检测到12种主要的转化产物,其转化途径主要包括羟基化、氯取代、二聚化、脱酰化和氧化反应.通过发光菌实验对溶液毒性进行分析,3种工艺条件下ACE溶液的毒性都会有所升高,其中氯化工艺最为突出.每种工艺中不同的反应活性物质导致了ACE转化产物的不同,最终使得溶液毒性不同程度地升高.

As a typical pharmaceutical,acetaminophen( ACE) has aroused critical concerns owing to its widespread existence and potential toxicity. In this work,ACE degradation by chlorination,UV/H2O2 and UV/chlorine processes was inverestigated. The results showed that ACE could be degraded completely by both UV/Cl and UV/H2O2 processes,and the degradation rate by UV/Cl was higher among the two processes. The degradations processed by UV/H2O2 and UV/chlorine were well fitted by pseudo first order kinetics with the rate constant( kobs,ACE) of 0. 1343 min-1and0.0657 min-1( 293 K,pH= 7),respectively. The p H experiments indicated that,compared to other conditions,the degradation efficiencies of chlorination and UV/chlorine at acidic pH were much higher. Differently,the degradation efficiency of UV/H2O2 was slightly changed with pH. Themineralization of ACE was much more difficult than the degradation,and the highest mineralization efficiency was only 5. 60%( UV/Cl process) after 60 minutes. Twelve possible transformation products( TPs) were detected in UV/chlorine process,and the transformation path was mainly included hydroxylation,chlorine substitution,dimerization,deacylation and oxidation. Luminescent bacteria experiments were introduced to evaluate the toxicity of the solutions. It was found that the toxicity of the ACE solutions all increased after the three processes,in which chlorination was the most prominent. The different reactive species in each process caused ACE to transform to different TPs,ultimately leading to the different degrad of increases of the solution toxicity.