Degradation and mineralization of aniline by O_3/Fenton process enhanced using high-gravity technology

The degradation and mineralization of aniline(AN) using ozone combined with Fenton reagent(O_3/Fenton) in a rotating packed bed(RPB) was proposed in this study, and the process(RPB-O_3/Fenton) was compared with conventional O_3/Fenton in a stirred tank reactor(STR-O_3/Fenton) or single ozonation in an RPB(RPB-O_3). Effects of high gravity factor, H_2O_2 dosage, H_2O_2 dosing method and initial p H on the AN mineralization efficiency were investigated in the RPB-O_3/Fenton process. In addition, the behavior of Fe(II) was monitored at different H2 O2 dosing methods and p H values. Finally, the optimal operation conditions were determined with high gravity factor of100, initial pH of 5, Fe(II) concentration of 0.8 mmol·L^(-1) and H_2O_2 dosage of 2.5 ml. Under these conditions, for aniline wastewater at the volume of 1 L and concentration of 200 mg·L^(-1), a fast and thorough decay of AN was conducted in 10 min, and the TOC removal efficiency reached 89% in 60 min. The main intermediates of p-benzoquinone, nitrobenzene, maleic acid and oxalic acid were identified by liquid chromatography/mass spectroscopy(LC/MS), and the degradation pathways of AN in RPB-O_3/Fenton system were proposed based on experimental evidence. It could be envisioned that high-gravity technology combined with O_3/Fenton processes would be promising in the rapid and efficient mineralization of wastewater.

Degradation kinetics and mechanisms of phenolin photo－Fenton process

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.

Removal of citrate and hypophosphite binary components using Fenton,photo-Fenton and electro-Fenton processes

Both citrate and hypophosphite in aqueous solution were degraded by advanced oxidation processes （Fe^2＋/H2O2, UV/Fe^2＋/H2O2, and electrolysis/Fe^2＋/H2O2） in this study. Comparison of these techniques in oxidation efficiency was undertaken. It was found that Fenton process could not completely degrade citrate in the presence of hypophosphite since it caused a series inhibition. Therefore, UV light （photo-Fenton） or electron current （electro-Fenton） was applied to improve the degradation efficiency of the Fenton process. Results showed that both photo-Fenton and electro-Fenton processes could overcome the inhibition of hypophosphite, especially the electro-Fenton.

电芬顿法(Electro-Fenton Process)处理废水

电芬顿法(electro-Fenton)是在Fenton试剂的基础上,在二价铁离子(Fe2+)和过氧化氢(H2O2)作用下,产生强氧化性的羟基自由基(●OH)并由其氧化难降解废水,其中Fe2+和H2O2分别由电化学过程产生。本文概述了电芬顿过程的基本原理,通过介绍国内外电芬顿的发展情况,详细介绍了电芬顿的影响因素,包括pH、阴极电极、催化剂及其他因素等,并展望了其未来的发展方向。

Investigations on the Degradation of Triazine Herbicides in Water by Photo-Fenton Process

In this work, the degradation of 2-chloro-4,6-diamino-1,3,5-triazine in aqueous solutions by photo-Fenton process has been investigated. The preliminary results have shown that the degradation of 2-chloro-4,6-diamino-1,3,5-triazine by photo-Fenton process is more rapid and more effective than Fenton and UV/H2O2 processes. The effects of certain experimental parameters on kinetics and efficiency of the degradation of 2-chloro-4,6,-diamino-1,3,5-triazine by photo-Fenton process, have been evaluated. Under optimal conditions, photo-Fenton process achieved more than 90% of chloride release and about 30% of nitrate formation. The results of total organic carbon (TOC) and total Kjeldahl nitrogen (TKN) analyses have shown that no carbon dioxide and ammonia are formed during photo-Fenton treatment of aqueous solutions containing 40 mg/L triazine. These results indicate that only substituent groups of triazine ring are released;however, nitrogen atoms of triazine ring remain unaffected. A simple mechanism of degradation of 2-chloro-4,6-diamino-1,3,5-triazine has been proposed. The degradation starts by a rapid release of chlorine atoms as chloride ions to form 2-hydroxy-4,6-diamino-1,3,5-triazine. The amino groups of 2-hydroxy-4,6-diamino-1,3,5-triazine undergo are oxidized into nitro groups by hydroxyl radicals to form 2-hydroxy-4,6-dinitro-1,3,5-triazine which undergoes a slow release of nitro groups and their substitution with hydroxyl groups to form cyanuric acid and nitrate ions. The degradation of cyanuric acid by photo-Fenton process has also been investigated. The results of TOC and TKN analyzes show that no carbon dioxide is formed during the treatment.

Personal Review:Progress and prospect in electro-Fenton process for wastewater treatment

As a novel advanced oxidation process (AOP), electro-Fenton process is powerful for degrading most organic compounds including toxic and non-biodegradable ones, and so has attracted great attention. This paper reviews this process in detail including the mechanism, electrolytic bath, electrode materials, aerations and operation parameters. The application of electro-Fenton method in wastewater treatment is evaluated and summarized. Future work in this field is suggested, and three main directions of new electrode exploitation, development of assisted technologies and mechanistic study should be strengthened.

Reuse of Ferric Sludge by Ferrous Sulfide in the Fenton Process for Nonylphenol Ethoxylates Wastewater Treatment

In this paper, Fenton process was determined to be an effective technique to treat the refractory Nonylphenol ethoxylates (NPEOs) wastewater. The COD removal efficien-cies above 89% were obtained when the initial COD concentration was 12000mg/L. However, A large number of ferric sludge (SS=8.724g/L) would be produced after the Fenton oxidation of the wastewater and must be disposed appropriately. A novel process for Fenton sludge reused by low-cost ferrous sulfide (FeS) was also investi-gated. Experimental results show that the Fenton sludge could be reduced to produce a certain amount of Fe2+ in the acidic mixed liquor by ferrous sulfide. This mixed liquor from Fenton sludge could be used as the new catalyst in the Fenton process and was also highly effective for the NPEOs wastewater treatment. The residual ferrous sulfide from the mixed liquor could be used for the next batch of the

Life cycle assessment of homogeneous Fenton process as pretreatment for refractory pharmaceutical wastewater

The applicability of the life cycle assessment(LCA)to the Fenton process should be considered not only at the laboratory-scale but also at the full-scale.In this study,the LCA process was applied to evaluate the homo-geneous Fenton process for the treatment of high salinity pharmaceutical wastewater.The potential environmental impacts were calculated using Simapro software implemen-ting the CML 2001 methodology with normalization factors of 1995 world.Foreground data obtained directly from the full-scale wastewater treatment plant and labora-tory were used to conduct a life cycle inventory analysis,ensuring highly accurate results.By normalized results,the Fenton process reveals sensitive indicators,primarily toxi-city indicators(human toxicity,freshwater aquatic toxicity,and marine aquatic toxicity),as well as acidification and eutrophication impacts,contributed by hydrogen peroxide and iron sludge incineration,respectively.Overall,hydrogen peroxide and iron sludge incineration contribute significantly,accounting for at least 78%of these indicators.In sludge treatment phase,treatment of iron mud and infrastructure of hazardous waste incineration plants were the key contributors of environmental impacts,adding up to more than 95%.This study suggests the need to develop efficient oxidation processes and effective iron sludge treatment methods to reduce resource utilization and improve environmental benefits.

Synthesis of plant-based biogenic jarosite nanoparticles using Azadirachta indica and Eucalyptus gunni leaf extracts and its application in Fenton degradation of dicamba

Bio-jarosite,an iron mineral synthesized biologically using bacteria,is a substitute for iron catalysts in the Fenton oxidation of organic pollutants.Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts,are highly recyclable,and can be treated efficiently.This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles syn-thesized with green methods using two distinct plant species:Azadirachta indica and Eucalyptus gunni.The focus was on the degradation of dicamba via Fenton oxidation.The synthesized nanoparticles exhibited different particle size,shape,surface area,and chemical composition characteristics.Both particles were effective in removing dicamba,with removal efficiencies of 96.8%for A.indica bio-jarosite iron nano-particles(ABFeNPs)and 93.0%for E.gunni bio-jarosite iron nanoparticles(EBFeNPs)within 120 min of treatment.Increasing the catalyst dosage by 0.1 g/L resulted in 7.6%and 43.0%increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min^(-1) and 0.023 min^(-1),respectively,confrming their catalytic roles.Additionally,the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions.

铁铜双金属复合类Fenton催化剂的制备及用于处理阿莫西林模拟废水研究

针对粉末状类Fenton催化剂难以回收再利用的难题,采用煅烧法制备球形铁铜双金属复合催化剂,优化了催化剂制备条件(成分配比、煅烧条件和氮气流量),表征了催化剂的表面形态,考查了阿莫西林降解动力学,探讨了催化剂催化机理,并利用以该催化剂为核心的类Fenton催化体系处理阿莫西林模拟废水。反应在最优条件下阿莫西林去除率可达到99.9%。

基于Fenton氧化法的垃圾渗滤液处理研究进展

Fenton氧化法是一种高效的污水处理技术,能够有效地处理垃圾渗滤液。本文综述Fenton氧化法处理垃圾渗滤液的研究进展,分析Fenton氧化法处理垃圾渗滤液的原理,并探讨它们的优缺点,展望发展前景,以更好地将Fenton氧化法应用于垃圾渗滤液处理领域。

UV/Fenton/均相铜类Fenton氧化处理紫菜加工废水COD及色度研究

以COD和色度作为评价指标,采用均相Fenton、Cu-Fenton、UV/Fenton、UV/Cu-Fenton体系处理紫菜加工废水,探究了在室温条件下不同初始pH值、Fe^(2+)和Cu^(2+)投加量、H_(2)O_(2)投加量等因素对出水COD和色度的去除效果,通过正交试验确定了最佳反应条件,同时对反应机理进行了分析。分析显示羟基自由基(·OH)是UV/Fenton/均相铜类Fenton体系去除紫菜废水中COD及色度的主要活性基团。在最佳反应条件下,UV/Fenton体系在100 min时出水COD为40 mg/L,色度为25,比无UV时最佳反应时间缩短了50 min;UV/Cu-Fenton体系,在60 min时出水COD为35 mg/L,色度为20,比无UV时最佳反应时间缩短了一半,UV/Fenton体系和UV/Cu-Fenton体系出水COD及色度均能达标排放。

Fenton法处理化学实验室有机废水

Fenton法具有氧化性强,操作便捷,反应迅速安全稳定等优点,对于高浓度有机废水有较好的实验效果。本文采用Fenton法对攀枝花学院化学实验室产生的有机废水进行处理,通过单因素实验,探讨了FeSO_(4)·7H_(2)O投加量、H_(2)O_(2)投加量、pH值、反应温度和反应时间等五个因素对有机废水COD去除率的影响。单因素实验结果表明:在pH值=3,H_(2)O_(2)投加量为2.0 mL/100mL,FeSO_(4)·7H_(2)O投加量为0.5 g/100mL,反应温度为50℃,反应时间为60 min,COD去除率达到最大为83%。在单因素的基础上,进行了正交实验,结果表明:四个影响因素对实验结果影响大小的顺序为:R2(pH)>R1(Fe^(2+)/H_(2)O_(2))>R4(反应时间)>R3(温度),四因素的最佳组合为:pH值=3,温度为50℃,Fe^(2+)/H_(2)O_(2)=1∶4(摩尔比),反应时间60 min。动力学分析得出该反应更加符合二级反应动力学。

Fenton-铁氧体一步工艺处理锕系核素污染分析废液研究

为了高效地对锕系核素污染分析废液进行处理,为同时含有锕系核素及有机物的废水的处理提供指导,提出Fenton-铁氧体一步处理工艺,首先对该方法的配方进行了优化,然后探究了pH、温度对处理时间及处理效果的影响,最后验证该方法对不同活度废液的适应性。结果表明:将FeSO_(4)·7H_(2)O和H_(2)O_(2)的添加比例控制在3∶1,可在一步工艺中实现了Fenton氧化和铁氧体共沉淀,同时完成破络和核素去除。在废液与FeSO_(4)·7H_(2)O之比小于等于1 L∶1.85 g的条件下,该方法对总α比活度在10~2~10~7Bq/L量级范围的锕系核素污染废液均有较强的适应性,净化系数均超过100。当共沉淀pH与温度增加时,处理效果、效率均随之提升,沉淀物体积也进一步降低。可见相较于公开报道的Fenton氧化、铁氧体共沉淀两步处理工艺,所提出的一步工艺可明显减少处理过程中的铁泥沉淀量,简化操作步骤,更适合放射性操作环境。

Combination of the direct electro-Fenton process and bioremediation for the treatment of pyrene-contaminated soil in a slurry reactor

A combined treatment technology （DEF-BIO） using the direct electro-Fenton （DEF） process and bioremediation （BIO） was established in this study. The performance of the DEF-BIO process on the remediation of a pyrene （PYR）-contaminated soil was evaluated in a slurry reactor. The appropriate order of application was to conduct the DEF process followed by BIO, evaluated through analysis of the degradation characteristics of each process individually. In addition, the application time of the DEF process affected the efficiency of the combined process. The optimum time to apply the DEF process was determined through an analysis of the induced changes in PYR intermediates, pH, soil organic matter （SOM） and bacteria. The optimum application time of the DEF process was 6 h. All the induced changes were beneficial for the BIO phase. The removal of PYR was 91.02% for DEF- BIO after 72h, and the efficiency was almost 50% increased, compared with the individual DEF and BIO treatments. Therefore, the combined process of DEF-BIO process may be an efficient and promising method for the remediation.

Treatment of pharmaceutical wastewater containing recalcitrant compounds in a Fenton-coagulation process

The advanced treatment using integrated Fenton＇s reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB （upflow anaerobic sludge bed） and a SBR （sequencing batch reactor） process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry （GC-MS）, mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton＇s reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2＋=3：1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.

Fenton法处理生活垃圾渗滤液工艺方案分析及展望

综述了反应温度和时间、pH值、Fe^(2+)投加量、H_(2)O_(2)投加量以及H_(2)O_(2)Fe^(2+)投加比例对Fenton法处理生活垃圾渗滤液效果的研究,在详细分析Fenton法分解污染物机理的基础上,结合生活垃圾渗滤液经Fenton法处理后的产物特征,建议将Fenton法用于生活垃圾渗滤液处理,并对Fenton法用于生活垃圾渗滤液达标处理进行了展望。

S/C对Fenton处理切削液的优选与污泥分析

首次提出了以污泥产率指标(S/C)作为切削液废水处理的筛选指标,采用Fenton氧化法对切削液废水最佳运行参数进行优选并对其衍生污泥进行深度分析。结果表明:在m(Fe^(2+))∶m(H_(2)O_(2))(质量比)=1∶2、H_(2)O_(2)投加量为70 mL/L、水样初始pH=5.5、H_(2)O_(2)投加间隔时间为25 min(反应时间为100 min)的条件下,COD去除率最高达到81.67%,S/C值为最低的7.5×10^(-2)mL/mg。TG/DSC测试可知Fenton衍生污泥在500℃之前存在两段减重;XRD,SEM,XPS等测试表明污泥中吸附水及层间水的散失,水合氧化铁(HFO)转变为Fe2O3及FeOOH导致了这一现象。

Kinetics of Degradation of Eosin Y by One of the Advanced Oxidation Processes (AOPs)—Fenton’s Process

Kinetics of homogeneous degradation of Eosin Y (EY), also known as Acid red 87 (CI 45380), are studied, mostly using Fenton’s process, at 30℃ by monitoring its absorbance at 517 nm (λmax of EY). This process is one of the advanced oxidation processes (AOPs). Mixture of H2O2 and Fe(II) ion in acetate buffer medium (pH 2.74 - 4.56) generates hydroxyl free radicals (?OH) which attack the dye molecules, resulting in degradation of the dye molecules. Results show that the initial rate of EY degradation decreases with the increasing of solution pH because of removal of kinetically important Fe (iron) species through formation of ferric hydroxide. On the other hand, the rate increases with increasing the concentrations of H2O2, Fe(II) and EY at low solution pH. The initial rate increases with increasing of concentration of H2O2 and, subsequently remains unaffected with further increase of its concentration at a constant Fe(II) concentration because of the enhanced scavenging environment created by H2O2 at its higher concentration. The initial rate also increases with increasing of concentration of Fe(II) at a constant H2O2 concentration and remains unaffected with its further increase. EY concentration also enhances the initial rate at low pH. However, the initial rate is significantly enhanced by UV light. This is because of formation of additional hydroxyl radicals through excitation of the dye molecules by UV light. During the period of experiment, EY in aqueous solution alone hardly suffered any degradation. Degradation mechanism of EY by the Fenton and photo-Fenton’s processes is also discussed. Statistical analysis was used to validate the experimental results. Low values of the standard deviation for both the initial rate and % degradation indicated the consistency of the experimental data.

UV-Fenton工艺的研究进展及其在水环境微污染处理领域的应用

近年来,水环境中的新型难降解污染物受到广泛关注,催生了该领域大量降解、还原及吸附等处理技术的相关研究,尤其是基于强氧化性自由基的高级氧化法(AOPs),典型工艺就是Fenton法。但在传统Fenton氧化体系中,H_(2)O_(2)的利用效率较低,铁泥产量高,且pH限制范围较窄,影响了Fenton反应的整体降解效果及应用。因此,引入了紫外光以提高H_(2)O_(2)的分解效率,即UV-Fenton体系,较传统Fenton可以有效减少Fe^(2+)用量,促进Fe^(3+)向Fe^(2+)的转化,加速H_(2)O_(2)分解,并提高H_(2)O_(2)利用率,进而使有机物矿化更彻底。文章详细对比了传统Fenton与UV-Fenton工艺,介绍UV-Fenton工艺的反应原理,并讨论其影响因素(例如光照强度、Fe^(2+)和H_(2)O_(2)用量等),同时,文章总结了UV-Fenton工艺在水环境领域及微污染处理中的实际应用,包括有机染料、抗生素、农药及全氟化合物等。最后对UV-Fenton工艺的研究改进方向以及实际应用存在问题提出了展望。