电-Fenton及类电-Fenton技术处理水中有机污染物

传统Fenton技术是一种广泛用于水体里有机污染物降解的高级氧化技术(advanced oxidation technologies, AOTs)。它利用Fenton试剂Fe²⁺与H₂O₂反应生成具有强氧化性的羟基自由基(^·OH),从而降解有机污染物。基于相似的机理,过渡金属离子(Fe²⁺、Co²⁺和Ag⁺等)也可与过硫酸盐反应生成氧化能力较强的硫酸根自由基(SO₄^·-),而被称之为类Fenton技术。传统Fenton技术存在Fe²⁺投加量多,产生的铁污泥多等缺点,因此,有学者将Fenton技术与电化学技术结合,使Fe²⁺在阴极得以持续再生,这就是广为关注的电-Fenton技术。同样地,类Fenton技术也遇到与传统Fenton技术相似的问题。借鉴电-Fenton技术的成功应用,基于硫酸根自由基的类电-Fenton技术应运而生。本文在介绍电-Fenton和类电-Fenton技术原理的基础上,概括了电-Fenton和类电-Fenton技术的主要类型及其改进方法,并就值得深入研究的问题和热点趋势进行了展望。     

有毒有机污染物光化学降解及机理研究

水环境污染已成为全球性普遍关注的重要课题.Fenton氧化法和Fenton光化学氧化法由于它在处理废水中的有毒有机污染物方面呈现了其它处理方式不能取代的特点而具有广阔的应用前景.虽然Fenton氧化法是一种非常有效的废水处理方法,但是由于体系中大量的铁离子的存在,使得处理后的体系带有颜色,且沉降铁泥的处理大大增加了运行成本.此外,Fenton反应一般需要在pH小于3的酸性介质中进行及在反应过程中过氧化氢的利用率不高等不足都限制了该方法的广泛应用.在本文中,我们用铁络合物代替Fenton反应中的铁离子并首次把可见光引入到反应体系中氧化降解有机污染物,着重研究了铁络合物在可见光照射下在均相和异相反应体系中对有毒有机污染物的光催化降解动力学、光化学反应机理、微环境的影响、活性自由基的形成以及光降解产物等方面内容,并得出以下几个重要结论:     

臭氧氧化技术处理含抗生素废水*

本文详细介绍了臭氧氧化技术的基本原理,分析了臭氧投加量、反应温度、溶液pH值、UV、H₂O₂及催化剂等因素对臭氧氧化处理抗生素废水效果的影响。根据抗生素的不同分类,综述了近年来关于臭氧氧化技术处理β-内酰胺、大环内酯、磺胺、喹诺酮、四环素、氯霉素六类常见抗生素废水的研究进展,并展望了臭氧氧化处理抗生素等难降解有机废水的发展趋势以及所面临的主要问题。     

酚类化合物的氧化降解

电催化氧化技术是在Fenton反应过程的基础上,发展起来的新的高效氧化技术.该技术因反应条件温和、处理效率高、无二次污染等优点,近来被用于酚类废水的治理.     

Fenton及Photo-Fenton非均相体系降解有机污染物的研究进展

Fenton及photo-Fenton氧化法是一种有效的应用于环境污染物处理领域的高新氧化技术之一,对Fenton试剂的固定化可以减少铁离子的二次污染,提高催化能力和光利用率,及扩展pH等优势。本文综述了近年来Fenton及photo-Fenton非均相体系氧化降解有机污染物的研究状况。引用文献57篇。     

异相Fenton催化水污染控制

高级氧化技术(AOPs)是当前水处理研究领域的热点问题。异相Fenton催化氧化是一种极具代表性的高级氧化技术,其反应过程中产生的羟基自由基(·OH)等活性氧物种可以无选择性地攻击有机污染物,将有机大分子逐步分解为小分子物质,从而达到高效去除废水中有毒有害污染物的目的。相比均相Fenton反应,它具有pH响应范围广、不产生铁泥、催化剂可循环利用等优点。然而,由于固相催化剂的本征特性和局限性,当前所研究的异相Fenton催化剂仍存在中性条件下活性低、过氧化氢(H₂O₂)利用率低、Fe(Ⅲ)/Fe(Ⅱ)转化速率不高等问题,难以实现异相Fenton催化在环境修复领域的大规模应用。本文综述了不同活性氧物种参与的异相Fenton反应机理,总结了多种异相Fenton催化剂及其在有机污染物控制方面的应用,为继续开展异相Fenton催化水污染控制研究提供参考。     

高浓度甲醛废水预处理工艺研究

采用“尿素缩合-粉煤灰吸附-Fenton氧化”复合工艺来处理高浓度甲醛废水,对影响甲醛去除率的因素进行了试验探讨,并确定了工艺优化条件．用该工艺处理高浓度甲醛废水,甲醛的总去除率可达到99％以上,能满足最终生化处理的要求．     

基于铁化合物的异相Fenton催化氧化技术

异相Fenton催化氧化技术是一种非常有效的处理难生物降解有机污染物的方法,它可以在温和的条件下实现反应。作为均相Fenton的发展,异相Fenton具有容易分离并再利用和更宽的适用范围等优点。该文主要综述了常见的含铁物质作为异相Fenton催化剂降解有机污染物的发展,这些催化剂包括零价铁、氧化铁、羟基氧化铁、水铁矿和其他铁化合物等。全面介绍了Fenton反应的不同机理,包括自由基机理和高价铁机理。重点讨论了提高异相Fenton催化剂活性的发展,并指出催化剂的效率受其表面氧化态、比表面积、过渡金属掺杂种类和晶相等许多因素的影响。概述了提高异相Fenton催化剂催化效率的不同方法,包括减小催化剂尺寸到纳米尺度、将催化剂负载于高比表面积载体上、引入过渡金属(如Ti、Co、Mn、Cr和V)到催化剂结构中。另外,一类新颖的异相Fenton催化剂铁氧体受到特别的关注,这是由于它高的催化活性和稳定性。最后,对异相Fenton催化氧化技术的发展进行了展望。我们认为理想的异相Fenton催化剂要具有高的催化活性和H2O2利用率、良好的稳定性、宽pH应用范围和易于回收利用等特点。     

二氧化氯催化氧化难降解有机废水在我国的研究进展

难降解有机废水的处理对环境保护有十分重要的意义.在本文中,对用二氧化氯催化氧化技术在不同领域中难降解有机废水的处理和其催化氧化反应机理在我国的研究进展进行了介绍和评述,也指出了该技术未来的发展前景和进一步的研究方向.     

降解水中有机毒物的新型反应体系研究

利用空气中的氧电化学合成H₂O₂,制备具有较高电流效率的空气电极.将空气电极用于构成降解有机毒物的新型反应体系电化学氧化体系、光激发氧化剂氧化体系和光电-Fenton氧化体系.实验测量了H₂O₂在不同体系不同条件下的分解速率,并与相应的传统式体系作了比较.实验测量了苯胺在新型体系中的矿化反应速率,发现H₂O₂的分解速率与苯胺的矿化速率有良好的平行关系,其中H₂O₂分解速率最快的光电-Fenton体系是氧化降解有机分子的最佳体系.通过光电-Fenton体系和光-Fenton体系的比较,揭示了空气电极/溶液界面在光电-Fenton体系中所起的重要作用.初步讨论了苯胺分子在光电-Fenton体系中矿化反应的机制.     

Oxidative destruction of dinitrophenols by Fenton’s reagent in the presence of inorganic salts

The influence of inorganic salts on the kinetics of oxidation of 2,4-and 2,6-dinitrophenols by Fenton’s reagent, hydrogen peroxide, in the presence of iron(II) ions was studied.     

Impedimetric Detection of DNA Damage with the Sensor Based on Silver Nanoparticles and Neutral Red

Novel electrochemical DNA‐sensor based on glassy carbon electrode (GCE) modified with Ag nanoparticles, Neutral red covalently attached to its surface and native DNA adsorbed on modifier coating was developed for the estimation of DNA damage on example of model system based on Fenton reagent. As was shown, the oxidation process resulted in synchronous increase of electron transfer resistance and capacitance measured by electrochemical impedance spectroscopy (EIS). The contribution of each sensor component on the signal was specified and sensitivity estimated against similar surface coatings. The shift of EIS parameters was found to be higher than that of similar biosensors reported. The DNA sensor was tested on the estimation of antioxidant capacity of green tea infusions again the results of coulometric titration with electrogenerated bromine.     

芬顿试剂对田菁胶的氧化降解

考察了芬顿试剂对田菁胶的氧化降解行为. 系统研究了H_2O_2和Fe~(2+)用量、温度和降解时间对田菁胶粘度的影响. 结果表明,H_2O_2和Fe~(2+)合适的体积比为2:1. 在较低的温度(25 ℃)和较短的时间(20 min)内芬顿试剂就能使田菁胶粘度下降90%以上. 另外,pH值的变化对其降解性能影响不大,显示了较好的降解效果.     

Effects of Fenton’s reagent and thermal modification on the electrochemical properties of graphite felt for microbial fuel cell

Research on Chemical Intermediates - Effective methods for graphite felt (GF) treatment based on Fenton’s reagent treatment and thermal modification have been used to improve microbial fuel...     

芬顿试剂对田菁胶的氧化降解行为研究

本文考察了芬顿试剂对田菁胶的氧化降解行为。系统研究了H2O2和Fe2+用量、温度和降解时间对田菁胶粘度下降百分率的影响,并简单讨论了芬顿试剂对田菁胶的氧化降解机理。结果表明,H2O2和Fe2+的合适用量之比为2︰1。另外,只需较低的温度(25 ℃)和较短的时间(20 min),芬顿试剂就能使田菁胶粘度下降90%以上,显示了较好的降解效果。     

A review on advanced oxidation processes: From classical to new perspectives coupled to two- and multi-way calibration strategies to monitor degradation of contaminants in environmental samples

This paper offers a critical review from classical to new perspectives of advanced oxidation processes (AOPs) coupled to two- and multi-way calibration strategies based on multivariate curve resolution – alternating least-squares (MCR-ALS) and parallel factory analysis (PARAFAC) with various analytical techniques to monitor the degradation of contaminants in environmental samples. It focuses on the generation of highly reactive hydroxyl (HO•) radicals (classical AOPs with emphasis on Fenton, photo-Fenton and ozonation processes) and emerging reactive sulphate (SO₄^•−) radicals (new perspectives of AOPs) for effective degradation of recalcitrant compounds. Other new perspectives of AOPs were also addressed, namely semiconductor photocatalysis (TiO₂/UV), combination of processes involving at least one AOP (hybrid or single-step processes and sequential or two-step processes), novel advanced electrochemical oxidation technologies (electro-Fenton and electro-photo-Fenton) and nanocatalytic heterogeneous Fenton technology with high specific surface area. Literature reports since 2008 for real applications in the environmental remediation based on AOPs (from classical to new perspectives) coupled to PARAFAC and MCR-ALS with first-, second- and third-order data were reviewed and the improvements obtained were briefly discussed. The two- and multi-way calibration strategies allow one the successful decomposition of first-, second- and third-order data collected from different analytical techniques. Therefore, the respective profiles obtained allowed qualitative (spectral profiles) and quantitative (concentration profiles) analysis of complex samples during the degradation of contaminants through the second-order advantage. Finally, trends of future research directions for AOPs coupled to various analytical techniques and advanced chemometric models were provided.     

COD reduction of waste water streams of active pharmaceutical ingredient – Atenolol manufacturing unit by advanced oxidation-Fenton process

Active pharmaceutical intermediates (API) in waste waters have adverse effects on aquatic life and environment. The API have high COD value and low BOD₃ and hence difficult to treat biologically. In this study, advanced oxidation processes (AOPs) utilizing the H₂O₂/Fe⁺², Fenton reactions were investigated in lab-scale experiments for the degradation of Atenolol containing waste water streams. The experimental results showed that the Fenton process using H₂O₂/Fe⁺² was the most effective treatment process. With Fenton processes, COD reduction of wastewater can be achieved successfully. It is suggested that Fenton processes are viable techniques for the degradation of Atenolol from the waste water stream with relatively low toxic by-products in the effluent which can be easily biodegraded in the activated sludge process. Hence, the Fenton process with H₂O₂/Fe⁺² is considered a suitable pretreatment method to degrade the active pharmaceutical molecules and to improve the biodegradability of waste water.     

Decontamination of heavy metal complexes by advanced oxidation processes: A review

Heavy metal complexes with high mobility are widely distributed in wastewater from modern industries, which are more stable and refractory than free heavy metal ions. Their removals from wastewater draw increasing attentions and various technologies have been developed, among which advanced oxidation processes (AOPs) are more effectively and promising. Progresses on five representative types of AOPs, including Fenton (like) oxidation, electrochemical oxidation, photocatalytic oxidation, ozonation and discharge plasma oxidation for heavy metal complexes degradation are summarized in this review. Their rationales, advantages, applications, challenges and prospects are introduced independently. Combinations among these AOPs, such as electrochemical Fenton oxidation and photoelectrocatalytic oxidation, are also comprehensively highlighted. Future efforts should be made to reduce acid requirement and scale up for practical applications of AOPs for heavy metal complex degradation efficiently and cost-effectively.     

Treatment options for tannery wastewater II: integrated chemical and biological oxidation

This is the second of two papers each dealing with a specific technological option for replacing the Fenton's reagent with simpler processes for treating industrial wastewater. In particular, the paper reports the results of an investigation aimed to check, at lab scale, the effectiveness of an alternative wastewater treatment combining biological degradation and chemical oxidation with ozone. The treatment was carried out in a lab scale hybrid reactor fed with the biological stage effluent of a plant treating the wastewater of a large tanning district in Central Italy whose residual COD result still higher than the Italian COD Maximum Allowable Concentration (MAC) value (i.e., 160 mgO2/L) The results are very promising, considering that a removal efficiency of 41% (as COD) has been achieved by treating an influent characterized by a COD content fully biorefractory. In addition, the proposed treatment presents the significant advantage of no additional sludge production, as happens with commonly utilized tertiary processes (i.e. Fenton), that is characterized by high chemical sludge production.     

Fe‐DPA as Catalyst for Oxidation of Organic Contaminants: Evidence of Homogeneous Fenton Process

Fenton‐type reactions using transition metal complexes in the decomposition of hydrogen peroxide to hydroxyl radical generation have received special attention due to their advantages over classical homogeneous processes involving soluble iron salts. Thus, the goal of this study was to investigate the use of an iron complex with the ligand pyridine‐2,6‐dicarboxylic acid (dipicolinic acid or DPA) as a homogeneous catalyst for the oxidation of the quinoline. The synthesized iron complex showed a molar ratio of 1:2 metal/ligand and was efficient in the quinoline oxidation at pH values near neutrality. The tests were monitored by mass spectrometry that allows identification of the different intermediates and showed complete oxidation of the quinolone compound. Moreover, in order to shed some light on the formation of hydroxyl radicals and the overall reaction mechanism, some theoretical calculations at the DFT level were performed. The results of this study demonstrated that the iron‐DPA complex is a good catalyst for the oxidation of quinoline by a Fenton‐like mechanism. All theoretical data show good agreement with experimental results.