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利用臭氧(O_3)氧化降解酮洛芬(KET),采用淬灭实验探究了实验过程中KET的降解机理,鉴定了降解中间产物,推测了其降解路径,并且对KET降解过程中的急性毒性进行了评价.结果表明,臭氧能有效降解KET,其降解符合一级动力学.降解过程中臭氧和羟基自由基(·OH)共同作用于KET.KET降解过程中生成了21种主要产物,其中包括3-乙基二苯甲酮、3-(1-过氧化氢乙基)-二苯甲酮、3-(1-乙酰基)-二苯甲酮等产物,降解路径包括羟基化、脱羧基、脱甲基、侧链氧化、酮基断裂等.明亮发光杆菌急性毒性实验表明KET降解过程中生成了较母体更高风险的中间产物. 相似文献
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本文用ESR自旋捕集技术,以4-POBN为捕集剂,研究了吸烟烟气处理的鼠肝微粒体体系中的自由基性质。结果发现,在吸烟烟气处理的鼠肝微粒体中,4-POBN捕集到了自由基信号,这一信号的强度随温育时间的延长及充入烟气的量增加而增强,根据其性质及ESR波谱参数分析,体系中产生了脂类自由基。结果说明,吸烟烟气刺激了鼠肝微粒体的脂质过氧化。 相似文献
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在(298±3)K的温度下,采用相对速率法测得了3-甲基丁酮与OH自由基在气相中的反应速率常数:k=(2·6±0·4)×10~(-12)cm~3·molecule~(-1)·s~(-1).该结果与根据结构活性法估算的结果相一致.实验中还测定了该反应的主要产物:丙酮、甲醛和过氧乙酰基硝酸酯(PAN),讨论了该气体在NOx存在下与OH自由基反应的机理.根据上述实验结果讨论了3-甲基丁酮对对流层臭氧浓度的影响:3-甲基丁酮在大气对流层中的氧化反应活性不高,它的主要氧化产物丙酮同样具有低的反应活性.因此,3-甲基丁酮对大气中臭氧生成的贡献不是很大. 相似文献
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卤代醌是许多卤芳香持久有机污染物的致癌代谢产物和饮用水消毒副产物.13-过氧羟基-9,11-十八碳二烯酸(13-HPODE)是最为广泛研究的内源性脂质过氧化物.众所周知,过渡金属离子可以催化分解13-HPODE,但尚不清楚卤代醌是否可以通过不依赖金属离子的途径促进其分解;若是如此,又有什么特异性和相似性?我们发现卤化醌如2,5-二氯-1,4-苯醌(DCBQ)可显著促进13-HPODE的分解.综合采用电子自旋共振-自旋捕获、HPLC-MS和GC-MS等分析方法,可检测到反应形成的脂质烷基自由基如戊烷基自由基、7-羧甲基自由基以及具有基因毒性的4-羟基-2-壬烯醛(HNE)等.在DCBQ和13-HPODE的反应中也能检测到两种氯醌-脂质烷氧基耦合物.我们认为卤代醌促进内源性脂质过氧化物13-HPODE分解生成活性脂质烷基自由基和基因毒性的HNE是通过一类新型的金属非依赖亲核取代与裂解机理来实现的,这也在一定程度上解释了其潜在的基因毒性和致癌性. 相似文献
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紫外强化湿式催化过氧化氢氧化降解活性艳红X-3B的实验及机理分析 总被引:1,自引:0,他引:1
比较湿式催化过氧化氢氧化(CWPO)和光催化联合湿式催化过氧化氢氧化(UV-CWPO)对活性艳红X-3B的处理效果,结果发现后者具有较大的优势,反应150 min后,染料脱色率分别为84.10%和99.28%.动力学实验表明,两者均符合一级反应动力学方程,且相同反应温度下,UV-CWPO工艺表观动力学系数为CWPO工艺的1.64—2.75倍;两者表观活化能Ea分别为40.24 kJ·mol-1和32.79 kJ·mol-1,UV-CWPO工艺具有更低的反应活化能,意味着该工艺下染料分子更容易氧化为各种中间体,进而引起染料脱色.比较CWPO工艺和UV-CWPO工艺反应机理,发现两者在链的引发期不同,并通过叔丁醇作为羟基自由基捕获剂证实前者羟基自由基(·OH)产生量较后者更少.利用GC-MS检测分析CWPO工艺和UV-CWPO工艺降解活性艳红X-3B过程中产生的中间产物,结果表明两者产生了相同的中间产物,但是前者产生量明显更少,这说明UVCWPO工艺对活性艳红X-3B降解更充分. 相似文献
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利用衍生化气相色谱法对黄磷诱发氧化苯酚降解产物进行了研究,在磷酸存在下,以甲醇作酯类衍行生试剂,分别和SE-52和HP-17石英毛细管双柱结合GC-MS进行分离定性定量,黄磷诱发氧化苯酚降解产物以羧酸为主,在反应温度50℃时,表现为一级反应特征,速率常数(K):0.077min^-1,半衰期(t1/2):9.0min。 相似文献
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Gulnara M. Shaydullina Natalya A. Sinikova Albert T. Lebedev 《Environmental Chemistry Letters》2005,3(1):1-5
Ozone, chlorine and sodium hypochlorite are commonly used as disinfecting agents for drinking water production. The reaction pathways of ozonation and chlorination of o-methoxybenzoic acid in aqueous solution were studied using gas chromatography-mass spectrometry (GC-MS) and high pressure liquid chromatography (HPLC). The results show that less than 1% of o-methoxybenzoic acid remains in reaction. The final major products using ozone oxidation are oxalic and glyoxalic acids. Phenols appear only at insufficient ozone levels. Sodium hypochlorite leads to higher levels of primary products. Molecular chlorine leads to the formation of higher amounts of polychlorinated derivatives. Model experiments allow to propose schemes of o-methoxybenzoic acid transformation under the conditions simulating water treatment processes. 相似文献
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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. 相似文献
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植物体内水杨酸分析方法的探讨及其应用(Investigation and Application of Analysis Methods of Salicylic Acid in Plant Tissue) 总被引:1,自引:0,他引:1
准确测定植物中水杨酸的含量是深入研究其重要作用和抗病机理的必要前提.采用高效液相色谱(HPLC)对植物中内源水杨酸进行了分析,比较了紫外检测器和荧光检测器不同的检测结果,发现荧光监测器灵敏度更高,是紫外检测器的15倍.论文同时比较了使水杨酸与其他组分很好分离的液相色谱条件,结果表明,pH5.5的乙酸钠:甲醇(9:1,V/V)的流动相效果最好.用该方法测得的精密度的相对标准偏差为1.73%,重现性和稳定性均较好(稳定性的相对标准偏差为4.6%).论文以模式植物拟南芥(Arabidopsis thaliana)的野生型和水杨酸突变体两种类型为供试材料,对其体内水杨酸进行了提取测定,检测结果发现野生型体内的水杨酸的含量大约是水杨酸突变体的9倍,与文献报道吻合. 相似文献
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Unprecedented total mineralization of atrazine and cyanuric acid by anodic oxidation and electro-Fenton with a boron-doped diamond anode 总被引:1,自引:0,他引:1
This article reports the complete mineralization of atrazine. Atrazine has been the most widely used s-triazine herbicide.
Atrazine occurs in natural waters and presents a potential danger for public health because atrazine is considered as an endocrine
disruptor. The use of chemical, photochemical and photocatalytic advanced oxidation processes (AOPs) to decontaminate waters
containing atrazine only allowed its conversion into the cyanuric acid as ultimate end products, since it cannot be completely
degraded by hydroxyl radicals (•OH) produced by these techniques. The same behavior was previously reported for anodic oxidation and electro-Fenton with Pt
anode, although better performances were found using boron-doped diamond (BDD) anode but without explaining the role of generated
•OH. Here, the oxidative action of these radicals in such electrochemical AOPs has been clarified by studying the mineralization
process and decay kinetics of atrazine and cyanuric acid in separated solutions by anodic oxidation with BDD and electro-Fenton
with Pt or BDD anode using an undivided cell with a carbon-felt cathode under galvanostatic conditions. Results showed that
electro-Fenton with BDD anode was the more powerful treatment to degrade both compounds. Almost total mineralization, 97%
total organic carbon (COT) removal, of atrazine was only feasible by this method with a faster removal of its oxidation intermediates
by •OH formed at the BDD surface than that formed in the bulk from Fenton reaction, although the latter process caused a more
rapid decay of the herbicide. Cyanuric acid was much slowly mineralized mainly with •OH produced at the BDD surface, and it was not degraded by electro-Fenton with Pt anode. These results highlight that electrochemical
advanced oxidation processes (EAOPs) using a BDD anode are more powerful than the classical electro-Fenton process with Pt
or PbO2 anodes. 相似文献
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Chengyuan SU Weiguang LI Xingzhe LIU Xiaofei HUANG Xiaodan YU 《Frontiers of Environmental Science & Engineering》2016,10(1):37-45
A study of the decolorization of reactive brilliant blue in an aqueous solution using Fe-Mn-sepiolite as a heterogeneous Fenton-like catalyst has been performed. The Fourier transform infrared (FTIR) spectra of the catalyst showed bending vibrations of the Fe-O. The X-ray diffraction (XRD) patterns of the catalyst showed characteristic diffraction peaks of α-Fe2O3, γ-Fe2O3 and MnO. A four factor central composite design (CCD) coupled with response surface methodology (RSM) was applied to evaluate and optimize the important variables (catalyst addition, hydrogen peroxide dosage, initial pH value and initial dye concentration). When the reaction conditions were catalyst dosage= 0.4 g, [H2O2]= 0.3 mL, pH= 2.5, [reactive brilliant blue]o = 50 mg·L−1, and volume of solution= 500 mL at room temperature, the decolorization efficiency of reactive brilliant blue was 91.98% within 60 min. Moreover, the Fe-Mn-sepiolite catalyst had good stability for the degradation of reactive brilliant blue even after six cycles. Leaching of iron ions (<0.4 mg·L−1) was observed. The decoloring process was reactive brilliant blue specific via a redox reaction. The benzene ring and naphthalene ring were first oxidized to open ring; these were then oxidized to the alcohol and carboxylic acid. The reactive brilliant blue was decomposed mainly by the attack of ·OH radicals including surface-bound ·OH radicals generated on the catalyst surface. 相似文献
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本文用0.3mBenton-34/OV-1短填充柱气相色谱法研究了萘在焚烧炉飞灰上的氯化反直产物,实验表明,飞灰表面性质对氯化有促进作用,这种促进作用与飞灰的来源或表面性质有强烈关系,文中对有关分析方法和萘在焚烧炉飞灰上氯化反应的结果作了讨论。 相似文献
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利用量子化学计算气相中锌离子各种水合和水解形态的几何结构、电荷分布以及水合和水解反应的Gibbs自由能变和焓变.结果表明,除了水合锌离子外,锌离子各种水解络合物的配位数均小于6;对于深度水解产物Zn(OH)3^-和Zn(OH)4^2-,内层无水分子的键合.水合作用和水解作用互相抑制,水合作用阻碍了水解产物进一步水解(Zn(OH)2除外),水解作用使得水合变得困难.内层键合水分子数的增加降低了水合形态中Zn上的电荷,使得水解形态Zn上的电荷升高. 相似文献