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INTRODUCTION For the degradation of high concentration wast- ewater with toxic and non-biodegradable pollutants, the UV/Fenton method has been proposed in recent years (Braun et al., 1991; Bossmann et al., 1998). The UV/Fenton system relies mainly on oxidative degradation reactions, where organic radicals are generated by photolysis of the organic substrate or by reaction with hydroxyl radicals. These radical intermediates are subsequently trapped by dissolved molecular oxygen and lea… 相似文献
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INTRODUCTION Fenton process has been well studied recently for its prospective applications in unmanageable wastewater treatment (Legrini et al., 1993; Ollis and Al-Ekabi, 1993; Prousek, 1996). The high effi-ciency of this process is traditionally thought to be due to the generation of hydroxyl radical (HO?, which is of a high oxidation potential (E0 = 2.80 V) and can mineralize the organic compounds com-pletely to water and carbon dioxide. In acidic me-dium, this radical mechanism ca… 相似文献
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Phenol degradation in photochemically enhanced Fenton process was investigated in this work. UV-VIS spectra of phenol degradation showed the difference between photo-Fenton process and UV/H2O2, which is a typical hydroxyl radical process. A possible pathway diagram for phenol degradation in photo-Fenton process was proposed, and a mathematical model for chemical oxygen demand (COD) removal was developed. Operating parameters such as dosage of H2O2 and ferrous ions, pH, suitable carrier gas were found to impact the removal of COD significantly. The results and analysis of kinetic parameters calculated from the kinetic model showed that complex degradation of phenol was the main pathway for removal of COD; while hydroxyl radicals acted weakly in the photo-Fenton degradation of phenol. 相似文献
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Cr(VI) and phenol are toxic contaminants that need to be treated, and different methods have been researched to simultaneously remove these two contaminants from industrial wastewater. In this study, Cr(VI) was used as a novel Fenton-like catalyst in phenol degradation by H2O2. In the pH range of 3.0‒11.0, the degradation efficiency of phenol decreased with elevated pH. At pH = 3.0, 100 mg/L phenol was effectively degraded by 2 mmol/L Cr(VI) and 20 mmol/L H2O2. At pH = 7.0 and the same conditions as those of pH = 3.0, 79% of 100 mg/L phenol was removed within 6 h, which was an improvement in pH limitation compared with the Fe(II)-mediated Fenton reaction. Quenching experiments indicated that ·OH generated from the catalysis of H2O2 by Cr(V) instead of Cr(VI) was the primary oxidant that degraded phenol. When pyrophosphate was added in the Cr(VI)/H2O2 system, complexes with the Cr(V) intermediate rapidly formed and inhibited H2O2 decomposition, implying that the decomposition of H2O2 to ·OH was catalyzed by Cr(V) instead of Cr(VI). The presence of anions such as chloride and sulfate had insignificant effect on the degradation of phenol. TOC and UV analyses suggest that phenol could not be completely oxidized to CO2 and H2O, and the intermediates identified by high performance liquid chromatography further indicates that maleic acid and benzoquinone were intermediates which may be further degraded into short chain acids, primarily maleic, formic, acetic, and oxalic acids, and eventually into CO2 and H2O. Considering that more than 50% Cr(VI) can also be removed during this process, the Cr(VI)/H2O2 system is more appropriate for the simultaneous removal of Cr(VI) and phenol contaminants from industrial wastewater.
相似文献5.
李锐 《兰州石化职业技术学院学报》2014,(4):8-10
通过正交实验和单因素实验探索了Fenton氧化炼化废水中苯酚的最佳工艺条件。实验结果表明,Fenton试剂处理苯酚废水时,各影响因素的作用大小顺序是:p H反应温度H2O2投加量反应时间Fe SO4·7H2O投加量;最佳氧化反应条件为:p H=3.5,反应温度为20℃,H2O2投加量为12 m L·L-1,反应时间为30min,Fe SO4·7H2O投加量为450 mg·L-1,此时废水中苯酚的去除率为89.26%,残余苯酚含量为11.76 mg·L-1。因此,用Fenton氧化法处理含苯酚废水是一种非常有效的方法。 相似文献
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介绍了UV/Fenton试剂的反应机理,分析了其在各类废水处理中的应用.作为一种新的废水处理技术,UV/Fenton对难生物降解污水净化作用较好,但对初始酸度、色度要求较高. 相似文献
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Para-tert-butyl phenol (p-TBP) and 2,4-di-tert-butyl phenol ( 2,4-DTBP) are wi.dely used for the preparation of antioxidants. Zeolite catalysts showed good performance for the synthesis of p-TBP and 2,4-DTBP. In this work, zeolite H-mordenite (HM) catalyst was prepared and the alkylation of phenol with tert-butyl alcohol over zeolite HM catalyst was investigated at different reaction conditions. It is found that increasing temperature enhances the selectivity to p-TBP and the optimum reaction temperature for phenol conversion is 438 K. Increasing flow rate decreases phenol conversion apparently while the selectivity to p-TBP has a little increase. The suitable tert-butyl alcohol/phenol molar ratio is 2. Lower alcohol/phenol molar ratios are beneficial to p-TBP while higher ones are helpful for producing 2,4-DTBP. 相似文献
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以直接耐酸大红染料(4BS)为模拟污染物,对4BS染料废水进行了非均相光助紫外Fenton(UV／Fenton)体系氧化降解试验研究,通过测量废水4BS及化学需氧量(CODcr)的变化,考察了不同氧化体系、H2O2投加量、催化剂投加量、pH值等主要操作条件对4BS废水处理效果的影响。结果表明,在H2O2投加量为1倍理论投加量(1 Qth),复合催化剂的投加量为O．2 g·L-1,常温不通气的情况下,经过40 min,4BS染料废水CODcr的去除率可达80％以上,4BS染料的去除率达到95％以上,废水的可生化性也得到很好的改善。该方法为非均相UV／benton体系应用于染料废水处理提供了很好的应用前景。 相似文献
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研究UV254光照下,Fe(Ⅲ)-EDTA/H2O2对苯酚的催化光降解效能。首先考察反应时间、溶液初始pH值、Fe(Ⅲ)与EDTA的浓度比值对UV/Fe(Ⅲ)-EDTA催化光降解苯酚的影响,进而考察UV/Fe(Ⅲ)-EDTA/H2O2体系对苯酚的降解效能。结果表明:当溶液pH为7,Fe(Ⅲ)/EDTA浓度比值为1:1时,经过1h反应,UV/Fe(Ⅲ)-EDTA体系对苯酚的催化光降解效率达61.13%。在溶液初始pH为37时,UV/Fe(Ⅲ)-EDTA对苯酚的降解率均可达60%以上。在中性条件下,UV/Fe(Ⅲ)-EDTA体系添加H2O2后可把苯酚的降解率从61.13%提高到91.30%。反应前后溶液的紫外扫描光谱表明光降解过程中苯酚的苯环共轭结构被破坏。最后对UV/Fe(Ⅲ)-EDTA/H2O2体系催化光降解机理进行了初步探讨。 相似文献
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Fenton及类Fenton试剂的研究进展 总被引：5，自引：0，他引：5
Fenton法是近几年备受关注的一种新的废水处理高级氧化技术.概述了羟基自由基·OH的产生机理,介绍了Fenton法和类Fenton法的运行机理及存在的优缺点,阐述了Fenton试剂及光/Fenton、光/H2O2草酸铁络合物、微波/Fenton以及超声/Fenton等类Fenton试剂的氧化特性,对各类试剂在工业废水处理上的应用状况进行了总结. 相似文献
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采用二氧化钛光催化结合掺硼金刚石电催化来提高污染物氧化效率.以苯酚作为模型废水污染物,分别比较了采用BDD电催化和TiO2光催化以及两者结合方法的降解过程,研究了电流密度和初始浓度等条件对降解效果的影响,并进行了反应动力学讨论.实验结果表明：与单独处理相比, BDD和TiO2组合处理方法拥有较优的苯酚去除效果,尤其是先电解后光催化的方式,其最优工作电流密度为25.48mA/cm2,并且随着苯酚初始浓度增加,去除率随之下降.动力学研究表明反应符合准一级动力学方程. 相似文献
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周美珍 《宁德师专学报(自然科学版)》2014,(1):24-26
采用Fenton试剂氧化降解亚甲基蓝.结果表明：Fenton氧化过程中,H2O2溶液的用量、FeSO4溶液的用量及pH对反应都有影响,当溶液初始pH为3、0.1％Fe2镕液和0.3％H2O2溶液的用量分别为7 mL和2mL,亚甲基蓝初始浓度为10mg/L时,反应2min后亚甲基蓝的降解率可达99.6％以上,证明了Fenton试剂可以有效得处理亚甲基蓝废水. 相似文献
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通过溶胶-凝胶法分别制备了掺杂Fe^3＋、Cu^2＋的TiO2.以日落黄为目标降解物,研究Fe^3＋、Cu^2＋掺杂TiO2为催化剂的紫外光催化反应,考察了金属离子的掺杂量、催化剂的加入量、光照时间、溶液pH值、溶液初始浓度对脱色率的影响.结果表明：Fe3＋掺杂对提高TiO2光催化活性的效果优于Cu^2＋掺杂.在Fe^3＋、Cu^2＋掺杂比为1.5%,Fe^3＋、Cu^2＋掺杂催化剂用量分别为0.04、0.1 g/L,紫外光催化降解2 h,pH为10,初始浓度为6 mg/L的日落黄100 mL的条件下,Fe^3＋、Cu^2＋掺杂的催化剂脱色率分别达92.14%、58.68%. 相似文献
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制备了磷钨杂多酸季铵盐-磷钨酸四甲基铵并对其进行了初步表征。在光催化反应仪中,以紫外灯为光源,以磷钨酸四甲基铵为光催化剂,探讨了光催化降解苯酚的最佳条件。实验结果表明,对于10mg／L的苯酚溶液。催化剂投加量为1．5g／L,在300W高压汞灯照射下,光催化降解8h,去除率可达89．9％,TOC去除率达85．1％。 相似文献
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Black clay(BC) was used as a catalyst for the decolorization of Azure B dye by Fenton process. BC was modified by acid, alkali, distilled water, and calcination to check their changes in characterization and efficiency on decolorization of Azure B. Among three modified catalysts, maximum decolorization was obtained by acid-modified BC(AMBC) catalyst due to the highest removal of impurities, comparatively. The characterization of AMBC was done by Fourier-transform infrared spectroscopy and X-ray diffraction spectroscopy which show the presence of metal ion. The BET surface area, pore volume, pore size, and density of AMBC were calculated to be 79.402 m~2/g, 0.0608 m~3/g, 0.00306 nm, and 16 g/cm~3, respectively. The highest decolorization of 97.59% was achieved only in 10 min using AMBC at optimized calcination of 100 °C and 3 h of aging. AMBC was considered as the main catalyst for optimizing the different process parameters. Optimized conditions were obtained: pH 2, 0.2 mL of H_2O_2, catalyst dose 0.3 g, room temperature(30 °C), and stirring speed 400 r/min. The catalyst has showed excellent stability and reusability. It could remove more than 85% of color even after four cycles of run and less than negligible leaching of iron. AMBC has good recycling ability among other modified catalysts. To check the selectivity of catalyst, different dyes such as Congo red and mixed dye(mixture of Azure B and Congo red) decolorization were studied. In the present work, kinetic study was also carried out and a three-stage decolorization process was found. 相似文献
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中医临床文献与中医教学、科研、临床密切相关,包括与中医临床疾病的诊断、治疗有关的文献内容.系统深入地对中医临床文献进行整理研究,有利于提高中医教学、科研和临床学术水平.认为：中医病证名称整理是前提和关键,在此基础上,界定文献检索和收集的范围,综合运用目录学、版本学、训诂学等文献学的方法系统整理相关文献,建立重点病种文献数据库,进行数据分析挖掘研究,加强重点病种理论研究,最后形成重点病种中医临床综合防治方案. 相似文献
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利用Fenton试剂去除焦化废水中的氰化物 总被引：3，自引：2，他引：1
研究了在pH=3时,在Fenton试剂存在下,水中氰化物与Fe2＋、H2O2反应,通过分离生成的亚铁氰化铁沉淀,高效去除了氰化物。除氰过程中,Fenton起到了协同和强化作用,用于焦化废水的深度处理,总氰化物的去除率达到98%以上,浓度低于0.1mg/L,并有效地降低了水的浊度等指标。 相似文献
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采用高级氧化法修复敌百虫污染的土壤,考察了pH值、Fe2＋、H2O2、敌百虫初始浓度等因素对土壤中敌百虫去除效率的影响。结果表明,芬顿高级氧化法能有效地降解土壤中的敌百虫,最佳条件为水土比2∶1,初始pH值3.0,H2O2/Fe2＋的物质的量比25∶1。采用间歇式加入过氧化氢的操作方法,在污染土壤中加入Fenton试剂,敌百虫的降解率达到可达99.3%,并且其降解速率符合一级反应动力学规律。 相似文献
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Fe (Ⅲ)-catalyzed ozonation yielded better degradation rate and extent of COD (Chemical Oxygen Demand) or oxalic acid as compared with oxidation by ozone alone. Two parameters with strong effects on the efficiency of ozonation are pH of the solution and the catalyst (Fe3 ) dosage. The existence of a critical pH value determining the catalysis of Fe (Ⅲ) in acid conditions was observed in phenol and oxalic acid systems. The best efficiency of catalysis was obtained at a moderate concentration of the catalyst. A reasonable mechanism of Fe (Ⅲ)-catalyzed ozonation of phenol was obtained based on the results and literature. 相似文献