Degradation of recalcitrant compounds by catechol-driven Fenton reaction.

Dihydroxybenzenes are able to reduce Fe(III) and promote the Fenton reaction in the presence of H2O2. The catechol/Fe(III)/H2O2 system has been successfully used to degrade different compounds, being more efficient than the Fe(II)-Fenton reaction. In this paper the possibilities for using the catechol-driven Fenton reaction to degrade recalcitrant compounds such as the Fe(III)-EDTA complex and veratryl alcohol are reviewed.     

Fenton试剂氧化降解活性染料的试验研究

采用Fenton试剂对活性K - 2RL ,H -E2R ,HE - 3G ,X - 6B1Y ,X - 3B ,K - 2R ,H -E7B ,X - 4RN和S -F3B 9种染料所配水样进行处理 ,染料浓度为 4 0 0mg/L时 ,在FeSO4 浓度为10 0～ 180mg/L ,H2 O2 浓度为 2 4 0～ 5 40mg/L ,pH值为 3,反应时间为 1h ,温度为室温条件下 ,色度去除率达 95 %以上 ,COD去除率为 6 5 %～ 85 % ,TOC去除率为 70 2 %。反应前后的UV -VIS吸收光谱的比较表明 ,Fenton试剂对这 9种活性染料有着比较理想的降解效果     

Fenton and photo-Fenton treatment of a synthetic tannin used in leather tannery: a multi-approach study.

The aim of this work was to compare the behaviour of Fenton and photo-Fenton (UV-A, UV-C) processes to treat synthetic tannin (syntan) used in leather tannery which is one of the most polluting industries, releasing many xenobiotics. Both oxidation processes were performed at pH 3.0 and temperature 40-45 degrees C, which is the original temperature of the re-tanning process, in synthetic solutions containing 100 and 300 mg/L of COD equivalent of syntan. The efficiency of the applied oxidation processes was monitored by chemical oxygen demand (COD), oxidation redox potential (ORP) and aromaticity (UV280) and double bond (UV254) absorbance measurements. Acute toxicity test on Daphnia magna was performed to monitor toxicity in untreated and treated syntan solution. Gas chromatography-mass spectrometry (GC-MS) was applied to identify by-products of partial oxidation occurring in treated samples. The effective ratio of H2O2/FeSO4 for photo-Fenton processes was found to be feasible in terms of reagents used in the process.     

铁柱撑膨润土联合Fenton反应Fe离子溶出量的影响因素

通过简单的离子交换方法制取得铁柱撑膨润土,并利用透射电镜对原土、钠化土及铁柱撑膨润土进行研究,以酸性大红3R为目标污染物,考察pH值、焙烧温度、焙烧时间及反应时间对铁柱撑膨润土联合Fenton反应过程Fe离子溶出量的影响情况。结果表明,在其他条件相同的情况下,溶液酸性越强,Fe离子溶出量越大,在焙烧实验中,Fe离子溶出量由焙烧时间和焙烧温度共同决定。在一定反应时间内,Fe离子溶出量随反应时间延长呈先增大后减小趋势,并研究了铁柱撑膨润土表面酸性及比表面积与酸性大红3R色度去除率的关系。     

Fenton反应催化降解苯胺及影响因素研究

对Fenton反应催化降解水中苯胺和影响催化氧化效果的几种因素进行研究和探讨。试验表明,除废水pH,Fenton试剂用量是影响苯胺降解的主要因素外,水中Cl-也对催化性能产生明显的抑制作用。虽单纯的Fenton反应对苯胺的催化降解率可达98%以上,但CODCr去除率却相对较低,表明Fenton反应对苯胺降解后的某些中间产物难于再进一步矿化,而紫外线辐照可提高Fenton反应的催化降解性能和CODCr去除率,实现对某些中间产物的持续矿化作用。     

Fenton试剂处理选矿废水的试验研究

研究用Fenton试剂处理含苯胺黑药(二苯胺基二硫代磷酸)模拟废水和实际选矿废水,分别考查了反应初始pH值、Fe2+浓度及H2O2用量对COD去除率的影响。结果表明:氧化时间为10 min,反应初始pH值为4,ρ(Fe2+)=1.83 g/L,ρ(H2O2)=5.55 g/L,模拟废水苯胺黑药的质量浓度为300 mg/L时,COD去除率达到83.6%;对于实际废水,当ρ(Fe2+)=50mg/L,pH值=3.5,ρ(H2O2)=1800mg/L时,出水ρ(COD)从1000mg/L降到32 mg/L,COD去除率为96.8%,达到废水排放标准,药剂成本估计为每处理1 m3废水需要费用18元。     

New insights in the dihydroxybenzenes-driven Fenton reaction: electrochemical study of interaction between dihydroxybenzenes and Fe(III)

It has been reported that the dihydroxybenzene (DHB) driven Fenton reaction is more efficient to degrade recalcitrant substrates than the simple Fenton reaction. The enhanced reactivity of the DHB driven Fenton reaction is not clear, but it could be explained by the formation of oxidant species different from the ones formed by classical Fenton reaction or by the shift of the redox potential of the complex formed by DHB and Fe(III). The redox reaction between Fe(III) and the DHBs 1,2-dihydroxybenzene (catechol, CAT), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), and 1,2-dihydroxy-3,5-benzenedisulfonate (TIRON) was studied by cyclic voltammetry to better understand the enhanced reactivity of the DHB driven Fenton reaction. It was determined that the amount of Fe(II) produced by the redox reaction between Fe(III) and DHBs was insufficient to explain the enhanced reactivity. Cyclic voltammograms (CV) of the DHBs/Fe(III) systems show a quasi-reversible or irreversible behavior and also shifting and splitting the anodic peaks. This effect can be related to DHBs oxidation by Fe(III), but not to a real interaction.     

Fenton试剂预处理酵母废水的工艺研究

采用正交试验的方法研究了Fenton试剂预处理酵母废水的工艺过程,通过对CODCr和UV254的测定,对pH、H2O2、Fe2+、反应温度和初始CODCr,等因素的影响进行了探讨.结果表明,在正交试验得出的最优条件下,酵母废水的CODCr,去除率达到60.9%,UV254去除率达到87.3%,表征其可生化性的BOD/COD较原水提高了83.3%.水质得到较大改善.     

Microbial community of anammox bacteria immobilized in polyethylene glycol gel carrier

Anaerobic ammonium oxidation (anammox) is a recently discovered microbial pathway in the biological nitrogen cycle and a new cost-effective way to remove ammonium from wastewater. We have so far developed new immobilization technique that anammox bacteria entrapped in polyethylene glycol (PEG) gel carrier. However, fate and behavior of anammox bacteria in a gel carrier is not well understood. In the present study, we focused on the population changes of anammox bacteria in a gel carrier. Three specific primer sets were designed for real-time PCR. For quantification of anammox bacteria in a gel carrier, real-time PCR was performed. The anammox bacteria related to HPT-WU-N03 clone were increased the rate in anammox population, and found to be a major population of anammox bacteria in a gel carrier. Furthermore, from the results of nitrogen removal performance and quantification of anammox bacteria, the correlation coefficient between copy numbers of anammox bacteria and nitrogen conversion rate was calculated as 0.947 in total anammox population. This is the first report that population changes of anammox bacteria immobilized in a gel carrier were evaluated.     

Fenton氧化处理甲基橙染料模拟废水的动力学研究

采用Fenton试剂降解含甲基橙染料的模拟废水,通过对甲基橙染料处理过程中UV-Vis吸收光谱的分析,证明了Fenton氧化法对甲基橙染料的处理效果。进一步研究了Fenton氧化降解甲基橙废水的反应动力学,并建立了反应动力学模型。结果表明,Fenton氧化过程中,影响甲基橙降解速率的主要因素为H2O2和甲基橙的初始浓度。H2O2和甲基橙初始浓度与反应速率常数之间的关系可分别归纳为:kRH=0.05c(H2O2)1.4和kRH=0.023c(RH)-1.3。     

Decolorization and mineralization of Oolong tea polyphenols in colored soft drink wastewater by photo Fenton reaction

The decolorization and the mineralization of the colored soft drink wastewater including Oolong tea polyphenols by the photo Fenton reaction have been investigated. The decolorization of the colored soft drink wastewater including Oolong tea polyphenols by the photo Fenton reaction could be divided into 3 phases. Just after H2O2 was added to the solution, the color of the solution immediately increased from absorbance of 0.247 to 0.711 at the wavelength of 400 nm, which was defined as the 1st phase. Subsequently the significant decolorization by the photo Fenton reaction occurred at the 2nd phase. Finally, complete decolorization (the color attributed to the color of Fe3+) could be achieved in 180 min at the 3rd phase. The instantaneous and considerable color increase at the 1st phase could be attributed to the formation of intermediate colored compounds like quinones and soluble iron complexes produced by the Fenton reaction. About 95% mineralization of model colored soft drink wastewater with 229 mg L(-1) initial TOC concentration was achieved after 165 min.     

Survival of Campylobacter jejuni in potable water biofilms: a comparative study with different detection methods.

Campylobacteria are important foodborne pathogens. C. jejuni bacteria have caused several drinking water-related epidemics in Finland. Normally, C. jejuni is not able to multiply in drinking water or in biofilms although it may survive in biofilms. The survival of C. jejuni in biofilms was studied using the Propella biofilm reactor. The number of bacteria was analysed with traditional culture methods and with fluorescence in situ hybridisation (FISH). By culture methods C. jejuni was detectable for only 1 d after spiking whereas bacteria were found from biofilms for at least 1 week after spiking and from outlet water of the reactor for 3 weeks when using FISH. These results suggested that C. jejuni may survive in biofilms and culture methods probably seriously underestimate the real number in water and in biofilms.     

Fenton试剂对垃圾渗滤液的后处理

采用由H_2O_2和FeSO_4配制成的Fenton试剂,对垃圾渗滤液进行了后处理;考察了渗滤液的pH值,H_2O_2和FeSO_4的投加量及反应时间对COD和色度的去除效果。试验确定最佳条件为:pH值3.0,FeSO_41500mg/L,H_2O_220mL/L,反应时间60min,此时COD与色度去除率分别为79.7%和95.2%。     

Degradation of acid orange 7 by a controlled anaerobic-aerobic sequencing batch reactor.

The degradation of a mono azo dye in an automated and controlled anaerobic-aerobic sequencing batch reactor (SBR) is described in this work. The experiments were conducted with a synthetic wastewater containing acid orange 7 as the model compound to degrade and glucose as the co-substrate in a molar relationship 1:40 (substrate/co-substrate). It was possible to control the anaerobic and aerobic stages, using the redox potential (ORP) as the only control variable. The strategy detects an inflection point in the ORP signal, indicating the end of the reaction. The efficiency of removal of total organic carbon was between 85% and 90%. Azo dye was removed with 85% efficiency during the anaerobic stage.     

Enzymatic degradation of endocrine-disrupting chemicals in aquatic plants and relations to biological Fenton reaction

In order to evaluate the removal performance of trace phenolic endocrine-disrupting chemicals (EDCs) by aquatic plants, batch and continuous experiments were conducted using floating and submerged plants. The EDCs used in this study were bisphenol A, 2,4-dichlorophenol, 4-tert-octylphenol, pentachlorophenol, and nonylphenol. The feed concentration of each EDC was set at 100 μg/L. Continuous experiments showed that every EDC except pentachlorophenol was efficiently removed by different aquatic plants through the following reaction, catalyzed by peroxidases: EDCs+H(2)O(2)→Products+H(2)O(2). Peroxidases were able to remove phenolic EDCs in the presence of H(2)O(2) over a wide pH range (from 3 to 9). Histochemical localization of peroxidases showed that they were located in every part of the root cells, while highly concentrated zones were observed in the epidermis and in the vascular tissues. Although pentachlorophenol was not removed in the continuous treatment, it was rapidly removed by different aquatic plants when Fe(2+) was added, and this removal occurred simultaneously with the consumption of endogenous H(2)O(2). These results demonstrated the occurrence of a biological Fenton reaction and the importance of H(2)O(2) as a key endogenous substance in the treatment of EDCs and refractory toxic pollutants.     

Degradation of recalcitrant organic contaminants by solar photocatalysis.

Biological pre-treated landfill leachates of Djebel Chakir contains some macromolecular organic substances that are resistant to biological degradation. The aim of the present work is to assess the feasibility of removing refractory organic pollutants in biological pre-treated landfill leachate by solar photocatalyse process. Leachate pollutant contents are studied to assess their contribution to leachate pollution and their treatability by solar photocatalyse process. Phenol is chosen as model of pollutants, to evaluate its removal and the efficiency of the photocatalytic system. The experiments were carried out in suspended photocatalytic reactor, using TiO2 Degussa P25, under sunlight illumination (UV-A: 15-31 W/cm2). Under optimum operational conditions, applied to single reactant (phenol), the system presents a TOC removal of 90% (the degradation follows a first-order kinetic). Based on the TOC removal, the results shows that the degradation of biological pre-treated leachate follows a zero-order kinetic. After 5 h of sunlight exposure, 74% of COT is removed. The TOC removal is the best without any correction of the pH and at the TiO2 concentration of 2.5 g/L. The photocatalytic degradation of organic contaminants as well as the formation and disappearance of the by-products were followed by GC/MS. The solar photocatalysis processes induce several modifications of the matrix leading to more biodegradable forms: all the remaining and new compounds generated after the biological pre-treatment of leachate are degraded and other types of organics appear, mainly carboxylic acid, aliphatic hydrocarbons and phtalic acids.     

芬顿法深度处理造纸废水

利用芬顿(Fenton)法对造纸废水生化出水进行深度处理,考察了废水pH值、反应时间、FeSO4投加量和H2O2投加量对废水中色度和CODC r去除率的影响。结果表明:在pH值为5.00、FeSO4投量为400 mg/L、30%H2O2投量为200 mg/L,反应时间为30 m in,出水CODC r可降至60 mg/L以下,色度的去除率可达到74%,可以满足更为严格的造纸废水排放标准,为进一步的工程设计提供依据。     

Degradation of wine industry wastewaters by photocatalytic advanced oxidation.

Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.     

Fenton试剂-石英砂工艺处理铁锰矿井废水

针对铁锰矿井废水中锰离子难去除的问题,本试验采用Fenton试剂-石英砂工艺研究了锰离子的去除效率与机理。结果表明:加入H2O2比不加入对锰离子的去除效果好,各因素的最佳值分别为:当H2O2投加量为0.15mg/L、滤速为8 m/h,pH为7,石英砂粒径为1.0 mm时,锰的最高去除率可达到90.7%。     

采用Fenton试剂预处理糠醛废水的研究

采用Fenton试剂处理糠醛废水,主要考察了H_2O_2/Fe~(2+)的投配比、H_2O_2投加量、H_2O_2的投加方式和反应时间对废水COD和BOD去除率的影响.通过试验确定最佳反应条件为:H_2O_2/Fe~(2+)的投配比2∶1、H_2O_2投加量0.5 Q、H_2O_2分5批投加、反应时间80 min的条件下,糠醛废水的BOD/COD由原始的0.23提高到0.65左右,COD_(cr)去除率在52%左右.