共查询到19条相似文献,搜索用时 125 毫秒
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采用改良低温结晶法制备过碳酸钠(sodium percarbonate,SPC),对其进行XRD表征,并用以作为氧化剂构建类Fenton体系(SPC/Fe~(2+))降解亚甲基蓝(MB),对其降解的影响因素及反应动力学进行了研究。结果表明,在该体系中,当溶液初始pH分别为2~10时,亚甲基蓝的去除率在1 min时均可达到97%以上,说明该体系可高效去除水体中的亚甲基蓝,反应速率快,且过碳酸钠的使用可以拓宽Fenton反应的pH范围。该反应的最佳工艺条件为0.75 g·L~(-1)硫酸亚铁,300 mg·L~(-1)过碳酸钠,亚甲基蓝去除率在反应10 min后可达99.0%。亚甲基蓝在该体系中的降解遵循二级反应动力学方程,反应速率常数分别为64.50×10~(-3)L·(mol·s)~(-1),快于Fenton体系的17.83×10~(-3)L·(mol·s)~(-1)。该体系反应活化能为16.6 kJ·mol~(-1),远小于Fenton体系(46.234 kJ·mol~(-1)),说明以过碳酸钠为氧化剂更有利于非均相类Fenton反应的发生。 相似文献
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零价铁与双氧水异相Fenton降解活性艳橙X-GN 总被引:1,自引:0,他引:1
采用Fe0与H2O2构成异相Fenton体系降解偶氮染料活性艳橙X-GN,考察了初始pH、H2O2和Fe0投加量、温度等对反应过程的影响。实验结果表明,在初始pH值为3.0、Fe0投加量为0.8 g/L、H2O2投加量为5 mmol/L和反应温度30℃的条件下,反应60 min后活性艳橙降解率达到96.2%。Fe0与H2O2投加量都存在一个最佳范围,当Fe0与H2O2浓度大于0.8 g/L和5 mmol/L时,羟基自由基会通过其他方式消耗,致使活性艳橙降解率下降。酸性条件和提高温度均有利于反应的进行。反应符合准一级动力学,表观反应速率常数k为0.064 min-1(30℃),反应活化能为80.62 kJ/mol。UV-Vis光谱扫描表明,反应过程中活性艳橙的发色基团及苯环结构均被破坏。 相似文献
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《环境工程学报》2016,(4)
以TiO_2纳米管为阳极、石墨电极为阴极、泡沫镍颗粒为粒子电极组成新型的模拟太阳光协同三维电极/电Fenton(3D/SPEF)体系降解甲基橙。研究了该体系的协同处理效果,以及该体系降解甲基橙的影响因素和反应动力学。结果表明:模拟太阳光与3D/EF体系光电催化联合处理表现出良好的协同效应,其处理能耗仅为3D/EF的9/16;协同体系降解甲基橙过程的表观反应动力学总级数为0.97;通过单因素实验确定协同体系最优反应条件为:电压为15 V、初始p H为7、甲基橙初始浓度为50 mg/L、Fe~(2+)投加量为1 mmol/L,甲基橙的去除率达到93.77%,3D/SPEF体系在中性条件更有利于甲基橙的降解,克服了常规三维电极/电Fenton一般只能在酸性条件下进行的不足。 相似文献
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MnO2催化Fenton试剂降解苯酚废水 总被引:2,自引:1,他引:1
实验对MnO2催化Fenton试剂氧化高浓度苯酚废水的动力学特性和去除效果进行了研究。结果表明,MnO2可以提高Fenton试剂体系对苯酚的降解率以及COD的去除率;Fenton试剂以及MnO2催化Fenton试剂氧化苯酚废水体系中苯酚的降解都符合拟一级动力学模型。在MnO2催化Fenton试剂氧化体系中,苯酚的降解速率常数有明显提高,反应活化能也有所降低,说明MnO2的加入可以使反应容易进行。废水降解前后紫外可见吸收光谱和红外谱图表明,Fenton试剂法将苯酚可能降解为羧酸、烯烃等有机物中间体。 相似文献
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非均相UV/Fenton氧化法降解水中六氯苯的研究 总被引:8,自引:4,他引:4
采用超声辐照促进浸渍法制备了非均相UV/Fenton催化剂Fe/Al2O3,并对其进行了表征.以制备的催化剂对水中六氯苯进行非均相UV/Fenton法氧化降解.考察了铁的负载量、初始pH、H2O2投加量、催化剂投加量和反应时间对六氯苯降解效果的影响,并探讨了六氯苯的降解动力学规律.结果表明,制备的催化剂表面活性组分分散均匀,对六氯苯具有较高的催化活性和重复利用性.非均相UV/Fenton法降解六氯苯的最佳实验条件为:铁的负载量为2%,废水初始pH为3,H2O2和Fe/Al2O3催化剂的投加量分别为34 mg/L和150 mg/L,反应时间为20 min.在此条件下,浓度为500μg/L的六氯苯降解效率达94.5%.HCB的降解反应动力学规律可用Langmuir-Hinshwood方程很好地描述.六氯苯在催化剂表面的吸附常数为1.962 L/mg,表面反应速率常数为0.08 mg/(L·min). 相似文献
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芬顿氧化法处理水中酸性品红的研究 总被引:7,自引:2,他引:5
研究了酸性品红在Fenton体系中的降解过程,反应30 min后,在[Fe2+]0=0.06 mmol/L、[H2O2]0=0.3 mmol/L、pH=3、T=30℃的条件下,初始浓度为20 mg/L的酸性品红的去除率达到97%以上。升高反应温度,有利于Fenton体系中酸性品红的降解,但影响并不显著。根据不同温度下的速率常数,并结合Arrhenius方程求出了Fenton试剂降解酸性品红的反应活化能,仅为11.63 kJ/mol。C1?的存在对酸性品红在Fenton体系中的降解表现出明显的阻碍作用,并且随着C1?浓度的增加,抑制作用越来越大;SO24-和NO3-的存在也降低了Fenton试剂的氧化性能。 相似文献
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光助非均相Fenton体系用于活性艳红X-3B脱色的研究 总被引:1,自引:0,他引:1
在光助非均相Fenton体系中,采用一种稀土铈铁复合(CeFe)材料作为催化剂,并探讨了该反应体系在不同条件下活性艳红X3B的脱色效果。结果表明:该光助非均相Fenton反应在前10min符合一级反应动力学。采用掺杂0.08mol/L铈制备的CeFe材料对活性艳红X3B具有最佳的脱色效果,在pH3.0、H2O234mg/L、UV253.7nm条件下,10min内该反应体系速率常数k达到0.2456min-1,明显高于相同条件下的UV/H2O2(0.0446min-1)、UV/CeFe(0.0306min-1)体系的速率常数。 相似文献
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直接使用有机过渡金属化合物二茂铁作为催化剂,研究了非均相Fenton反应中亚甲基蓝的降解,并考虑了实际排放的印染废水中存在的无机助剂,进一步分析了典型无机助剂CuSO4、NaCl、Na2CO3、Na2SO4、Na2S的存在对该非均相Fenton体系的影响,结果表明:直接使用二茂铁做催化剂反应120min后,亚甲基蓝的剩余率为0.6%,羟基自由基的表观生成率为83.4%。NaCl、Na2CO3、Na2SO4、Na2S的加入会阻碍反应的进行,而CuSO4的加入会促进反应的进行。 相似文献
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2,3,7,8-Tetrachlorodibenzo-p-dioxin (2,3,7,8-TeCDD) was rapidly decreased by sonication in aqueous solution. The degradation efficiency was strongly influenced by ultrasonic power and reaction temperature. An initial 2,3,7,8-TeCDD concentration of 20 ng l(-1) was completely degraded within 60 min under sonochemical conditions using a 20 kHz frequency with a 150 W ultrasound power. The activation energy is 21.9 kJ/mol in the temperature range of 10-40 degrees C, suggesting a diffusion-controlled reaction. To increase the efficiency of 2,3,7,8-TeCDD treatment, degradation system combined ultrasound with Fe(III) (2 x 10(-4)mol l(-1)) and UV irradiation. Both UV and Fe(III) induced Fenton, Fenton-like and photo-Fenton reactions, leading to additional OH radicals and rapid 2,3,7,8-TeCDD removal. 相似文献
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Karthikeyan S Ezhil Priya M Boopathy R Velan M Mandal AB Sekaran G 《Environmental science and pollution research international》2012,19(5):1828-1840
Background, aim, scope
Treatment of wastewater has become significant with the declining water resources. The presence of recalcitrant organics is the major issue in meeting the pollution control board norms in India. The theme of the present investigation was on partial or complete removal of pollutants or their transformation into less toxic and more biodegradable products by heterogeneous Fenton oxidation process using mesoporous activated carbon (MAC) as the catalyst.Materials and methods
Ferrous sulfate (FeSO4·7H2O), sulfuric acid (36?N, specific gravity 1.81, 98% purity), hydrogen peroxide (50% v/v) and all other chemicals used in this study were of analytical grade (Merck). Two reactors, each of height 50?cm and diameter 6?cm, were fabricated with PVC while one reactor was packed with MAC of mass 150?g and other without MAC served as control.Results and discussion
The oxidation process was presented with kinetic and thermodynamic constants for the removal of COD, BOD, and TOC from the wastewater. The activation energy (Ea) for homogeneous and heterogeneous Fenton oxidation processes were 44.79 and 25.89?kJ/mol, respectively. The thermodynamic parameters ??G, ??H, and ??S were calculated for the oxidation processes using Van??t Hoff equation. Furthermore, the degradation of organics was confirmed through FTIR and UV?Cvisible spectroscopy, and cyclic voltammetry.Conclusions
The heterocatalytic Fenton oxidation process efficiently increased the biodegradability index (BOD/COD) of the tannery effluent. The optimized conditions for the heterocatalytic Fenton oxidation of organics in tannery effluent were pH 3.5, reaction time?C4?h, and H2O2/FeSO4·7H2O in the molar ratio of 2:1. 相似文献13.
Chao Zhang Lei Zhou Jie Yang Xinmin Yu Yonghai Jiang Minghua Zhou 《Environmental science and pollution research international》2014,21(14):8398-8405
In the present work, nanoscale zero-valent iron/activated carbon (NZVI/AC) was investigated as heterogeneous Fenton catalyst in three-dimensional (3D) electrode system for methyl orange (MO) degradation. Some important operating parameters such as cathodic potential, pH, and O2 flow rate were investigated, exhibiting good decolorization. The mineralization of MO was significantly improved by 20–35 % compared to two-dimensional (2D) AC system at the optimum conditions. Although the TOC removal of AC was higher than NZVI/AC due to its good adsorption capacity initially, heterogeneous Fenton catalysis played a more and more important roles in the following test. After eight runs, NZVI/AC still exhibited excellent catalytic properties with low iron leaching. Further, a relatively comprehensive mechanism of NZVI/AC as particle electrodes in 3D system was proposed. 相似文献
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Germán Cruz-González Carine Julcour Hélène Chaumat Valérie Bourdon Felipe Ramon-Portugal Sarra Gaspard 《Journal of environmental science and health. Part. B》2018,53(2):121-125
Intensive use of chlorinated pesticides from the 1960s to the 1990s has resulted in a diffuse contamination of soils and surface waters in the banana-producing areas of the French West Indies. The purpose of this research was, for the first time, to examine the degradation of two of these persistent pollutants – chlordecone (CLD) and beta-hexachlorocyclohexane (β-HCH) in 1 mg L?1 synthetic aqueous solutions by means of photolysis, (photo-) Fenton oxidation and ozonation processes. Fenton oxidation is not efficient for CLD and yields less than 15% reduction of β-HCH concentration in 5 h. Conversely, both molecules can be quantitatively converted under UV-Vis irradiation reaching 100% of degradation in 5 h, while combination with hydrogen peroxide and ferrous iron does not show any significant improvement except in high wavelength range (>280 nm). Ozonation exhibits comparable but lower degradation rates than UV processes. Preliminary identification of degradation products indicated that hydrochlordecone was formed during photo-Fenton oxidation of CLD, while for β-HCH the major product peak exhibited C3H3Cl2 as most abundant fragment. 相似文献
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Fe/活性炭多相类Fenton法湿式氧化罗丹明B废水的研究 总被引:9,自引:6,他引:3
采用自制的Fe/活性炭(Fe/AC)为催化剂,H2O2为氧化剂,组成多相类Fenton试剂催化降解罗丹明B染料废水。实验结果表明,在催化剂加入量为0.8 g/L,H2O2体积分数为0.3%,废水pH值为13,反应时间为30 min的条件下,质量浓度为200 mg/L的罗丹明B染料废水的脱色率达100%。反应动力学研究表明,罗丹明B脱色反应近似为一级反应,30℃时反应速率常数为0.02675 min-1,表观活化能为69.47 kJ/mol。 相似文献
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A. R. Laiju T. Sivasankar P. V. Nidheesh 《Environmental science and pollution research international》2014,21(18):10900-10907
Iron-loaded mangosteen shell powder (Fe-MSP) was found as an effective heterogeneous Fenton catalyst for the treatment of stabilized landfill leachate. Sonolytically produced catalyst has higher efficiency than other catalysts. At the optimal conditions (pH 3, catalyst concentration of 1,750 mg/L and hydrogen peroxide concentration of 0.26 M), 81 % of the chemical oxygen demand (COD) was removed effectively from the landfill leachate. But, the efficiency of Fe-MSP was reduced in the first recycling due to the poisoning of active sites. A metal leaching study indicated that the degradation of the pollutant is mainly due to solid Fe ions present in Fe-MSP rather than the leached ferrous and ferric ions. Hydroxyl radical production in the system was confirmed by the Fenton oxidation of benzoic acid. Compared to the homogeneous Fenton process, the heterogeneous Fenton process using Fe-MSP had higher COD removal efficiency, indicating the practical applicability of the prepared catalyst. 相似文献