Pathway of the ozonation of 2,4,6-trichlorophenol in aqueous solution

The reaction mechanism and pathway of the ozonation of 2,4,6-trichlorophenol (2,4,6-TCP) in aqueous solution were investigated. The removal efficiency and the variation of H₂O₂, Cl⁻ formic acid, and oxalic acid were studied during the semi-batch ozonation experiments (continuous for ozone gas supply, fixed volume of water sample). The results showed that when there was no scavenger, the removal efficiency of 0.1 mmol/L 2,4,6-TCP could reach 99% within 6 min by adding 24 mg/L ozone. The reaction of molecular ozone with 2,4,6-TCP resulted in the formation of H₂O₂. The maximal concentration of H₂O₂ detected during the ozonation could reach 22.5% of the original concentration of 2,4,6-TCP. The reaction of ozone with H₂O₂ resulted in the generation of a lot of OH• radicals. Therefore, 2,4,6-TCP was degraded to formic acid and oxalic acid by ozone and OH• radicals together. With the inhibition of OH• radicals, ozone molecule firstly degraded 2,4,6-TCP to form chlorinated quinone, which was subsequently oxidized to formic acid and oxalic acid. Two reaction pathways of the degradation of 2,4,6-TCP by ozone and O₃/OH• were proposed in this study. Translated from Acta Scientiae Circumstantiae, 2005, 25(12): 1619–1623 [译自: 环境科学学报]     

Photooxidation of hydrochlorofluocarbons and hydrofluorocarbons initiated by OH radicals

ＰｈｏｔｏｏｘｉｄａｔｉｏｎｏｆｈｙｄｒｏｃｈｌｏｒｏｆｌｕｏｃａｒｂｏｎｓａｎｄｈｙｄｒｏｆｌｕｏｒｏｃａｒｂｏｎｓｉｎｉｔｉａｔｅｄｂｙＯＨｒａｄｉｃａｌｓ￥ＺｈｏｎｇＪｉｎｘｉａｎ；ＭｕＹｕｊｉｎｇ；ＹａｎｇＷｅｎｘｉａｎｇ（ＲｅｓｅａｒｃｈＣ...     

微波解吸载乙醇活性炭的试验研究

针对酒精工业中产生的淡酒液用活性炭吸附 -微波解吸方法回收其中可利用的酒精。设计了固定床吸附器提纯淡酒液的流程 ,制定了活性炭吸附微波解吸的试验方案。结果表明 ,微波加热温度均匀 ,活性炭不会被过分加热分解 ,解吸速度快 ,能实现对被蒸发物质的选择加热 ,对要回收的物质可以浓缩回收     

大气过氧自由基测量研究进展

过氧自由基是大气中重要的氧化剂 ,其浓度的测定对于深入理解大气化学过程具有重要意义。本文总结了二十多年的研究成果 ,论述了大气过氧自由基测量的研究进展 ,介绍了带基体分离的电子自旋共振技术、远红外及毫米波发射光谱技术、激光诱导荧光技术以及化学放大法等常用测量方法及测量结果 ,并展望其未来的发展。     

不同离子在CCl4引发自由基反应中的作用及其环境生物学意义

报道了一种简便的ＣＣ１４体外引发自由基反应的模型，以小鼠肝匀浆脂质过氧化产物丙二醛（ＭＤＡ）的ＯＤ５３２ｍｍ值（ＭＤＡ－ＯＤ５３２ｍｍ）作为测定自由基反应的间接指标，研究了Ｈｇ＾２＋、Ｍｎ＾２＋、Ｎｉ＾２＋、Ｃｒ＾３＋、ＳｅＯ３＾２－等离子和Ｓs２Ｏ３水溶液在ＣＣ１４引发自由基反应体系中的作用。结果表明：Ｍn＾２＋能显著抑制自由基的生成，Ｃr＾３＋有一定的抑制作用，而ＨgＴ＾２＋对自由基产生有明显促进     

糖蜜酒精废液厌氧生物处理研究进展

综述了国内外糖蜜酒精废液厌氧生物处理的现状和综合利用的进展。     

Rate constants for the reaction of hydroxyl radicals with HFC-134a

ＲａｔｅｃｏｎｓｔａｎｔｓｆｏｒｔｈｅｒｅａｃｔｉｏｎｏｆｈｙｄｒｏｘｙｌｒａｄｉｃａｌｓｗｉｔｈＨＦＣ－１３４ａＺｈａｎｇＤｅｑｉａｎｇ，ＺｈｏｎｇＪｉｎｘｉａｎＲｅｓｅａｒｃｈＣｅｎｔｅｒｆｏｒＥｃｏＥｎｖｉｒｏｎｍｅｎｔａｌＳｃｉｅｎｃ...     

水解-混凝法处理糖蜜酒精废水试验

采用投加优势菌群的水解 -混凝法对糖蜜酒精废水进行试验 ,研究投加优势菌的水解阶段的处理效果 ,同时 ,以 10 %碱式AlCl3为混凝剂 ,对水解段的出水进行混凝处理 ,并对处理条件进行研究。结果表明 ,采用投加优势菌群的水解 -混凝法工艺处理该废水 ,可以取得 5 8%的CODCr去除率 ,且可去除一定的色度     

Persistence of methyl <Emphasis Type="Italic">tertiary</Emphasis> butyl ether (MTBE) against metabolism by Danish vegetation

BACKGROUND: Methyl tertiary butyl ether (MTBE) is the second most highly produced industrial chemical in the US and a frequent groundwater pollutant. At the same time, MTBE is quite persistent to biotic and abiotic decomposition. The goal of this study was to find plant species that could degrade MTBE and might be used in phytoremediation. METHODS: Excised roots and leaves (0.3 g) from more than 24 Danish plant species out of 15 families were kept in glass vessels with 25 ml spiked aqueous solution for 2 to 4 days. MTBE concentrations were 1 to 5 mg/L. Samples were taken directly from the solution with a needle and injected to a purge and trap unit. MTBE and the main metabolite, TBA, were measured by GC/FID. RESULTS AND DISCUSSION: Solutions with roots of poplar (Populus robusta) and a willow hybrid (Salix viminalis x schwerinii) produced TBA in trace amounts, probably stemming from bacteria. Significant MTBE reduction (> 10%) was not observed in any of the tests. Leaves from none of the species (trees, grasses and herbs) reduced the concentration of MTBE in the solution and no TBA, nor any other known metabolite of MTBE, was detected. CONCLUSION: It was not possible to find plants capable of efficiently degrading MTBE. This gives rise to the conclusion that plants probably cannot degrade MTBE at all, or only very slowly. RECOMMENDATIONS AND OUTLOOK: For phytoremediation projects, this has, as consequence, that the volatilization by plants (except with genetically engineered plants) is the only relevant removal process for MTBE. For risk assessment of MTBE, degradation by the plant empire is not a relevant sink process.