Characterisation of a laboratory electrochemical ozonation system and its application in advanced oxidation processes

An electrochemical reactor for oxygen/ozone production was developed using perforated planar electrodes. An electroformed -PbO₂ coating, deposited on a platinised titanium substrate, was employed as anode while the cathode was a platinised titanium substrate. The electrodes were pressed against a solid polymer electrolyte to minimise ohmic drop and avoid mixing of the gaseous products (H₂ and O₂/O₃). Electrochemical ozone production (EOP) was investigated as function of current density, temperature and electrolyte composition. Electrochemical characterisation demonstrated ozone current efficiency, Φ_EOP, ozone production rate (g h⁻¹), , and grams of O₃ per total energy demand (g h⁻¹ W⁻¹), increase on decreasing electrolyte temperature and increasing current density. The best reactor performance for EOP was obtained with the base electrolyte (H₂SO₄ 3.0 mol dm⁻³) containing 0.03 mol dm⁻³ KPF₆. Degradation of reactive dyes used in the textile industry (Reactive Yellow 143 and Reactive Blue 264) with electrochemically-generated ozone was investigated in alkaline medium as function of ozone load (mg h⁻¹) and ozonation time. This investigation revealed ozonation presents very good efficiency for both solution decolouration and total organic carbon (TOC) removal.     

活性炭强化臭氧氧化丙烯酸及酯废水的研究

生化后的丙烯酸及酯废水COD为550 mg/L,需进行深度处理才能达标排放。研究了活性炭强化的臭氧氧化工艺对该废水的处理效能,考察了废水碱度、活性炭装填高度、臭氧浓度和废水柱外循环流量对COD去除率的影响。实验结果表明,在最佳条件下反应2 h,废水COD可降至35 mg/L,达到《污水综合排放标准》(GB 8978—1996)中的一级标准要求。     

高级氧化处理有机污水技术进展

综述了高级氧化技术的原理，介绍了O3／UV、H2O2／UV、O3／H2O2组合过程及非均相TiO2光催化氧化等几种典型的高级氧化技术，阐述了高级氧化技术降解有机污水的机理以及在水处理中的应用进展。指出，高级氧化过程应用领域应扩展到水体中难降解的持久性有机污染物，并应加强高级氧化过程所需新型反应器的研制，以便进一步强化废水的5降解，提高其处理效率。     

Removal of diazinon by various advanced oxidation processes

Diazinon is a widely used organophosphorus insecticide that is an important pollutant in aquatic environments. The chemical removal of diazinon has been studied using UV radiation, ozone, Fenton's reagent, UV radiation plus hydrogen peroxide, ozone plus hydrogen peroxide and photo‐Fenton as oxidation processes. In the photodegradation process the observed quantum yields had values ranging between 2.42 × 10^?2 and 6.36 × 10^?2 mol E^?1. Similarly, the ozonation reaction gave values for the rate constant ranging between 0.100 and 0.193 min^?1. In the combined systems UV/H₂O₂ and O₃/H₂O₂ the partial contributions to the global oxidation reaction of the direct and radical pathways were deduced. In the Fenton's reagent and photo‐Fenton systems, the mechanism of reaction has been partially discussed, and the predominant role of the radical pathway pointed out. Additionally, the rate constant for the reaction between diazinon and the hydroxyl radicals was determined, with the value 8.4 × 10⁹ L mol^?1 s^?1 obtained. A comparison of the different oxidation systems tested under the same operating conditions revealed that UV radiation alone had a moderate oxidation efficiency, which is enhanced in the case of ozone, while the most efficient oxidant is the photo‐Fenton system. Copyright © 2007 Society of Chemical Industry     

Mineralization of bisphenol A by advanced oxidation processes

BACKGROUND: Endocrine disruptors, as in the case of bisphenol A (BPA), are increasingly found in aqueous effluents. The degree of mineralization of a bisphenol A (BPA) aqueous solution after applying several oxidation treatments has been investigated. RESULTS: UV‐C photolysis of BPA allowed calculation of the quantum yield, ϕ_λ=254 = 0.045 ± 0.005 mol Einstein⁻¹ but only 15% of the initial organic carbon content (TOC) was eliminated. Better results (80% conversion) were obtained after TiO₂ addition. Ozone inmediately reacts with BPA. Again, TiO₂ addition in the presence of O₃ was capable of increasing the mineralization level (60%). The photolytic ozonation of BPA was capable of completely eliminating TOC. The presence of activated carbon in the O₃/UV and O₃/UV/TiO₂ systems significantly enhanced the TOC removal reaction rate (100% conversion in 20 min). CONCLUSIONS: Processes such as ozonation or photolysis are capable of efficiently removing BPA from water however, mineralization levels are rather low. Addition of TiO₂ to O₃ or UV‐C significantly enhances TOC removal. The remaining organics still account for an average 20–40% of the initial organic carbon. The combination of O₃/UV‐C is capable of completely mineralizing BPA. Activated carbon and/or TiO₂ addition to the system O₃/UV‐C improves the TOC depletion rate. Copyright © 2008 Society of Chemical Industry     

UV/O_3高级氧化工艺深度处理垃圾渗滤液的研究

采用UV/O_3高级氧化组合工艺对垃圾渗滤液二级出水进行深度处理。研究反应时间、p H和臭氧进气流量等因素对处理效果的影响。结果表明,最佳工艺条件是p H=9、臭氧进气流量80 L/h、紫外光功率为10 W、反应时间120 min。在最佳工艺条件下,UV/O_3高级氧化组合工艺对垃圾渗滤液二级出水COD、氨氮、色度的去除率分别为80.61%、64.47%、91.70%,相比单独臭氧处理时,去除率分别提高了19.31%、17.77%、6.10%。     

高级氧化技术处理制药废水研究进展

本文综述了高级氧化处理技术在制药废水污染防治中的应用,对各种制药废水处理技术的特点及其在国内外研究的状况进行了讨论,探讨了污染防治中存在的问题及解决办法,最后对高级氧化技术处理制药废水的研究进行了展望.     

高级氧化技术在抗生素废水处理中的应用

抗生素制药废水是一类成分复杂、有机物含量高、色度深、含多种抑制菌物质、生物毒性大,难以生物降解的高浓度有机废水.文中简要介绍了高级氧化技术的原理、特点,重点阐述各种高级氧化技术作为抗生素制药废水的处理法,尤其是预处理法的优势及其应用进展,并在此基础上,对高级氧化技术处理抗生素废水的研究前景进行了展望.     

高级氧化技术降解吲哚的研究进展

吲哚散发粪便恶臭气味,广泛存在于焦化、染料、化工、制药和农药等工业废水中。由于其特殊的双环稠合结构,靠传统的生物水解断环提高吲哚的降解效果难以为继。本文全面介绍了吲哚的来源、毒性、危害及传统生物降解技术的缺陷,特别论述了高级氧化法（AOPs）中·OH的形成反应及降解吲哚的作用机理。传统AOPs能够高效降解吲哚,但价格昂贵,操作复杂,且使用剂量常受到其他物质的干扰,易引入新的污染物,难以在大规模的水处理工程中应用。因此,认为将AOPs预氧化与生物处理技术进行高效耦合是降解吲哚经济有效的办法。本文最后介绍了硫酸根自由基的高级氧化技术（SR-AOPs）耦合厌氧生物技术降解吲哚的研究及其优点。这些研究对丰富AOPs耦合生物处理技术理论、含氮杂环污染物高效降解及资源化利用有一定的参考价值。     

Advanced oxidation processes for the degradation of p‐hydroxybenzoic acid 1: Photo‐assisted ozonation

The oxidation of p‐hydroxybenzoic acid in aqueous solution by UV radiation and by photo‐assisted ozonation (UV+O₃) has been studied. The effects of temperature (10, 20, 30 and 40 °C), pH (2, 5, 7 and 9) and ozone partial pressure (0.10–0.38 kPa) on the conversion of p‐hydroxybenzoic acid were established. Experimental results indicated that the kinetics for both oxidation processes fit pseudo‐first‐order kinetics well. In the combined process, the overall kinetic rate constant was split into two components: direct oxidation by UV radiation (photolysis) and oxidation by free radicals (mainly OH·) generated in the system. The importance of these two reaction paths for each specific value of ozone partial pressure, temperature and pH was quantified. Lastly, a general expression is proposed for the reaction rate which takes into account the two reaction pathways and is a function of known operating variables. © 2001 Society of Chemical Industry     

高级氧化技术在持久性有机污染物处理中的应用

介绍了持久性有机污染物(POPs)的相关概念和性质,对几种典型的高级氧化技术在POPs处理中的应用现状作了较为详细的阐述,总结了各相关技术的基本原理及研究进展,并对其应用前景进行了评述。     

污泥生物炭基催化剂在高级氧化水处理的应用

污泥作为污水处理过程的残留物,含有多种重金属、有机物以及微生物等污染物,严重危害环境和人体健康.污泥衍生的生物炭基材料具有优良的孔隙结构、表面电荷分布以及含氧基团,在高级氧化水处理领域显示出极大潜力.目前,多种污泥生物炭基催化剂成功应用于光催化、过硫酸盐活化以及芬顿等氧化体系,显示出较高催化活性.系统地总结了污泥生物炭...     

高级氧化技术矿化水中痕量有机物能力的研究进展

综述了各高级氧化技术(AOPs)降解饮用水中痕量有机物的反应机制,并对痕量有机物的降解难易程度进行了动力学和热力学分析。分析表明:矿化反应Gibbs能判据与高级氧化技术降解难易程度存在一定关联,从而可有效地判断痕量有机毒物的降解难易程度。热力学分析方法可为高级氧化技术的动力学研究提供理论指导。     

rGO-Fe3O4活化过硫酸盐处理酸性红73

采用共沉淀法制备了还原石墨烯纳米片和磁铁矿复合材料（rGO-Fe₃O₄）。利用X射线衍射（XRD）、X射线光电子能谱（XPS）和透射电镜（TEM）对其进行了表征。以酸性红73（AR73）为目标物,研究了rGO-Fe₃O₄活化过硫酸盐（PS）处理酸性红73的效能,考察了催化剂投加量、PS浓度、溶液初始pH以及反应温度的影响。结果表明,室温下催化剂投加量为1.0 g/L、PS的浓度为1.0 g/L及初始pH为6.9时,10 min内50 mg/L酸性红73的脱色率达到100%。淬灭实验结果表明rGO-Fe₃O₄/PS反应体系同时存在SO₄^-?、?OH和单线态氧¹O₂,其中¹O₂的氧化反应起主导作用。复合材料rGO-Fe₃O₄不但活性高,而且便于分离,应用前景良好。     

高级氧化-生化耦合技术处理低浓度有机污水用作回用水实验研究

实验研究了臭氧高级氧化-生化耦合技术处理低浓度有机污水。以某炼油厂乙烯废水为例,在低臭氧投加量1 5～2 0mg/L及其他一定条件下,出水CODCr平均不到33mg/L,石油类污染物平均去除率达到了67 2%,出水挥发酚最高质量浓度仅0 016mg/L,硫化物平均降解率为65 2%,氨氮去除率保持在87 9%以上,优于活性炭处理方法。实验还发现,低剂量臭氧投加量的影响不如废水流量及水质变化影响显著,前者既可提高有机物的可生化性,又不会对微生物产生抑制作用。     

Removal of ampicillin sodium in solution using activated carbon adsorption integrated with H2O2 oxidation

BACKGROUND: The removal of antibiotic ampicillin sodium using H₂O₂ and modified granular activated carbon (GAC) is discussed. Two types of modified activated carbons were used in experiment to catalyze ·OH production from H₂O₂. One was modified with base (NaOH; called B‐GAC), the other was modified with Fe(NO₃)₃ (Fe‐GAC) and the nominal Fe metal loading was 5 wt%. In the experiment, pH, contact time, dosage of activated carbon and H₂O₂ and initial concentration of ampicillin sodium were investigated to determine their influence on the removal efficiency. The stability of Fe‐GAC was also evaluated. RESULTS: With an initial ampicillin sodium concentration of 200 mg L^?1, 85.2% of chemical oxygen demand (COD) and 76.4% of total organic carbon (TOC) can be removed with 8.0 g L^?1 of B‐GAC and 80 mg L^?1 of H₂O₂ (at pH 5.0). For the Fe‐GAC/H₂O₂ process, with 5.0 g L^?1 of activated carbon and 80 mg L^?1 of H₂O₂, COD and TOC removal can be elevated to 91.2% and 79.5% (at pH 3.0), respectively. CONCLUSION: The integration of activated carbon and H₂O₂ treatment was more effective for the removal of ampicillin from aqueous solution than using activated carbon alone. In the process, adsorption played a dominant role and the addition of a small amount of H₂O₂ accelerated the reaction rate and improved the removal efficiency. pH also greatly affected removal efficiency. Copyright © 2011 Society of Chemical Industry     

高级氧化技术降解水中药物及个人护理品的研究进展

目前,药物和个人护理品(PPCPs)在城市污水厂出水和水环境中频繁检出,已经引起了越来越多的关注.常规的污水处理工艺、饮用水处理工艺对PPCPs的降解都极其有限.高级氧化技术能高效降解PPCPs,且降解后其生化性大幅提高.全面阐述了03/H<,2>O<,2>、TiO<,2>光催化氧化、UV/H<,2>O<,2>、Fen...     

气液等离子体过程强化技术及其在高级氧化过程的应用

气液等离子体过程强化技术是20世纪80年代发展起来的一门新兴交叉学科,在高级氧化过程、液相化学合成和纳米材料制备等领域具有巨大的研究与应用价值。从化学工程的角度理解,气液等离子体过程强化技术的本质是特殊外场作用下的多相传递与反应过程,其中涉及高能电子碰撞、化学活性组分氧化、紫外光解和冲击波等多种物理与化学作用。由于气液等离子体过程强化技术本身的复杂性及多学科交叉性,对其复杂的物理与化学耦合机理还未得到充分认识,同时缺乏对气液等离子体反应器的系统研究及设计指导,从而极大程度地限制了该技术的进一步应用和发展。为全面认识气液等离子体过程强化技术,本文综述了近年来有关气液等离子体过程强化技术的诊断及机理研究进展,并剖析了气液等离子体反应器的设计思路,同时回顾和展望了气液等离子体高级氧化过程的最新研究进展,讨论了气液等离子体过程强化技术的研究方向。     

Eightfold increased membrane flux of NF 270 by O3 oxidation of natural humic acids without deteriorated permeate quality

BACKGROUND: Membrane fouling by humic acids limits the water recovery of nanofiltration in drinking water production. This article investigates if membrane fouling can be reduced by decomposition of humic acids in the concentrate stream by O₃ oxidation. RESULTS: At a specific O₃ dose of 2.11 g O₃ per g COD (17.0 g m^?3 O₃ (g) for 20 min), a COD reduction of 38% and a hydrophobic COD reduction of 69% is achieved. The membrane permeability of the ozonated solution by NF 270 membranes is higher (20.6 × 10^?9 L s^?1 m^?2 Pa^?1) than the permeability if the untreated solution is filtered (2.4 × 10^?9 L s^?1 m^?2 Pa^?1). The COD retention of the ozonated solution was similar to the retention of the untreated samples. The addition of H₂O₂ allows a better mineralization degree, i.e. UVA removal increased from 53% to 66% if H₂O₂ was added as from 10 min oxidation at the same molar flow rate as O₃. CONCLUSION: O₃ oxidation can substantially alleviate membrane fouling by humic acids in nanofiltration systems and the addition of H₂O₂ can slightly improve its decomposition. Copyright © 2010 Society of Chemical Industry