基于UV/H_2O_2和UV/PS工艺降解水体中磺胺吡啶研究

采用高级氧化技术-紫外/双氧水(UV/H_2O_2)和紫外/过硫酸盐(UV/PS)工艺降解磺胺吡啶(SPY)。研究表明,紫外与氧化剂(H_2O_2、PS)联用可显著提高去除率,其反应符合拟一级动力学模型。目标污染物磺胺吡啶的去除率在一定浓度内随着氧化剂H_2O_2和PS浓度升高而升高;磺胺吡啶初始浓度越大,反应速率越小;UV/H_2O_2工艺降解磺胺吡啶最大去除率发生在p H=3,而UV/PS工艺降解SPY在p H=11时去除率最大;Na Cl会抑制UV/H_2O_2和UV/PS工艺对目标污染物的降解,而适当的Na HCO_3可促进降解反应的进行;腐植酸对UV/PS工艺产生抑制作用,低浓度腐植酸(≤1 mmol/L)对UV/H_2O_2工艺则有促进作用。     

UV/H_2O_2和UV/TiO_2降解磺胺甲噁唑的研究

采用UV/H_2O_2和UV/TiO_2两种工艺降解磺胺甲噁唑(SMX),确定了H_2O_2和TiO_2的最佳投加量,在保持最佳投加量的条件下研究了SMX初始浓度、反应溶液初始pH、叔丁醇投加量对两种方法降解SMX效果的影响,为研究两种方法在降解SMX过程中的矿化程度测定了TOC的去除情况。结果表明,两种方法都对SMX具有较好的去除效果,整体而言UV/H_2O_2对SMX的降解速率高于UV/TiO_2;UV/H_2O_2的降解速率更易受到SMX初始浓度、反应溶液初始pH的影响;UV/H_2O_2对SMX的降解过程中·OH的氧化作用和UV直接降解都是去除SMX的主要作用,而UV/TiO_2中UV直接降解和空穴直接氧化是去除SMX的主要作用。     

UV/H_2O_2体系六氯苯降解途径探讨

实验采用了UV/H_2O_2体系氧化降解工艺对HCB进行降解实验,并分别考察了在p H、H_2O_2浓度、HCB浓度等单因素条件和不同氧化条件下的实际氧化降解效果,并进行了GC、GC-MS、IC扫面分析和氧化机理分析。结果表明:在室温条件下,H_2O_2的添加浓度对降解效率起到了决定性作用,当H_2O_2浓度在0.1 mol/L条件下时,降解效果最好为57.6%;不同氧化降解条件实验表明,在UV/H_2O_2协同氧化条件下,要优于两者单独氧化降解,表明H_2O_2和UV在氧化过程中产生了协同促进租用;根据GC、GC-MS、IC扫面分析,表明中间产物中主要是氯苯酚类化合物。     

UV/H2O2降解水中含氮消毒副产物-苯乙腈的动力学和影响因素

采用UV/H_2O_2高级氧化技术处理水中含氮消毒副产物苯乙腈,研究了影响苯乙腈降解的因素。结果表明,单纯UV体系中,去除效果不明显。UV/H_2O_2对苯乙腈具有较高的去除率,且降解符合一级反应动力学。随着过氧化氢投加量增大,苯乙腈的去除率呈先增大后减小的趋势,且在投加量为20 mg/L时可达94.9%;溶液初始浓度的增加会提高去除效果,且动力学速率常数增加;降低溶液pH值、增大紫外辐射剂量有利于降解速率和去除率的提高;自来水为基质对降解苯乙腈的影响不明显;Cl~-、Mg~(2+)、Al~(3+)对苯乙腈去除有一定的抑制作用,抑制率达20.9%以上。文中将UV/H_2O_2高级氧化技术应用于控制苯乙腈,以期为水中苯乙腈的降解提供基础理论。     

Fe~(2+)强化UV/H_2O_2降解水中喹啉的研究

采用UV/H_2O_2体系来降解水中的喹啉,研究了氧化剂投加量和溶液初始pH值对喹啉降解效果的影响,同时考察了Fe⁽²⁺⁾强化UV/H_2O_2体系对喹啉的降解率和矿化率的影响。结果表明,当喹啉初始浓度(C_0)=15 mg/L、紫外光照强度(I_0)=8.96 mW/cm(2+)强化UV/H_2O_2体系对喹啉的降解率和矿化率的影响。结果表明,当喹啉初始浓度(C_0)=15 mg/L、紫外光照强度(I_0)=8.96 mW/cm²、反应温度为25℃时,在pH=7.01、[H_2O_2]∶[QL]=40的条件下,反应60 min后,喹啉的去除率为41.11%,反应120 min后,TOC的去除率为32.89%。控制上述反应条件不变,向原反应体系中加入Fe2、反应温度为25℃时,在pH=7.01、[H_2O_2]∶[QL]=40的条件下,反应60 min后,喹啉的去除率为41.11%,反应120 min后,TOC的去除率为32.89%。控制上述反应条件不变,向原反应体系中加入Fe⁽²⁺⁾,当[Fe(2+),当[Fe⁽²⁺⁾]∶[H_2O_2]=1∶65时,喹啉和TOC的去除率分别提升至90.90%和65.07%。喹啉的降解过程符合一级动力学方程(R(2+)]∶[H_2O_2]=1∶65时,喹啉和TOC的去除率分别提升至90.90%和65.07%。喹啉的降解过程符合一级动力学方程(R²≥0.960),Fe2≥0.960),Fe⁽²⁺⁾强化前后,喹啉的降解速率常数(k_(obs))由0.008 5 min(2+)强化前后,喹啉的降解速率常数(k_(obs))由0.008 5 min^(-1)增加至0.063 8 min(-1)增加至0.063 8 min^(-1)。采用每一对数减小级电能输入(E_(Eo))指标对两种工艺的电能效率进行评估,结果表明,Fe(-1)。采用每一对数减小级电能输入(E_(Eo))指标对两种工艺的电能效率进行评估,结果表明,Fe⁽²⁺⁾的加入显著减小了UV/H_2O_2体系的电能消耗,研究结果可为实际工程提供参考。     

UV/Fenton-Fe~0降解水中阿特拉津动力学及影响因素

研究采用Fe~0非均相UV/Fenton技术去除水中阿特拉津(ATZ)。结果表明,UV/Fenton-Fe~0技术能够实现水中ATZ的快速去除,当p H为3.0,H_2O_2、Fe~0的质量浓度分别为17、25 mg/L时反应速率最快,5 min后ATZ去除率可达97.5%,反应符合准1级降解动力学。初始ATZ含量升高,反应速率降低,ATZ的绝对去除量增加。UV/Fenton-Fe~0体系拓宽了p H适用范围,在初始p H为3.0~7.0时,反应7 min后ATZ去除率均达到95%以上。水中少量天然有机物(TOC的质量浓度5~10 mg/L)对ATZ降解有明显促进,ATZ降解速率较纯水基质中提高7倍以上。水中Cl-和SO42-的存在对UV/Fenton-Fe~0过程也有明显促进,而NO3-则表现为抑制;自由基抑制实验证实了降解过程符合·OH氧化机理。     

磺胺吡啶在光助-二茂铁/H_2O_2非均相体系中的降解

抗生素在地表水中广泛检出,且可诱导细菌菌群抗药性,因而发展新型抗生素的去除技术势在必行。本研究基于二茂铁(Fc)良好的可逆化学特性、难溶于水、环境友好特性发展了一种光助-二茂铁/H_2O_2(Fc+H_2O_2+UV)氧化技术。以水环境中经常检出的磺胺吡啶为模型化合物,研究了磺胺吡啶在该氧化体系中的降解行为。研究结果发现,相对于常见的Fenton体系,磺胺吡啶在Fc+H_2O_2+UV体系中呈现出优异的降解效率。自由基淬灭实验发现·OH是主导磺胺吡啶降解的最主要活性物种。自由基探针实验证实Fc+H_2O_2+UV体系中存在电子转移过程,H_2O_2接受电子后产生·OH进而促进磺胺吡啶降解。     

UV/Fenton处理磺化泥浆体系钻井废水

采用UV/Fenton氧化处理磺化泥浆体系钻井废水,考察了H2O2和Fe2 物质的量比、H2O2投加量和pH值等对废水处理的影响.结果表明,UV/Fenton氧化不仅能有效去除钻井废水中的有机污染物,还可提高钻井废水的可生化性.随着H202投加量的增加,有机污染物去除率也相应的提高.当H2O2投加量为理论值的1.5倍(1.5 Qth)时,反应180 min,化学需氧量(COD)可从586 mg/L降到90 mg/L,去除率达到84.6%,出水COD符合国家一级排放标准;当H2O2投加量为0.6 Qth时,反应30 min,生化需氧量和化学需氧量的比值(BOD/COD)可从0.03提高到0.45.增大Fe2 投加量可提高有机污染物降解速率,但不能增加COD的去除率.反应适宜的pH值为3～5.建立了有机污染物降解动力学模型,模型和实验结果符合较好.     

UV/H_2O_2高级氧化处理苯酚废水研究

本文采用UV/H_2O_2实验室装置对苯酚人工配水进行处理试验研究,试验结果表明:在UV灯功率为500W,pH值7.0左右,H_2O_2:COD摩尔比为2:1,反应240min后COD由1045mg/L降至小于20mg/L,去除率高达99%以上。考察了不同pH(4.0,7.0和9.0),双氧水投加量与投加方式(一次投加和多次投加),以及氯离子浓度(0mg/L,2000mg/L和10000mg/L)对UV效果的影响,发现pH偏中碱性,H_2O_2:COD摩尔比2:1且一次性投加有利于COD的降解,而正常情况氯离子浓度对UV/H_2O_2的效果影响不明显。     

UV/H_2O_2高级氧化+MBR工艺处理垃圾渗滤液的研究

采取UV/H_2O_2+膜生物反应器组合工艺深度处理垃圾渗滤液,研究工艺对有机物及氨氮处理效果。结果表明,当工艺条件为双氧水投加量为2.1 g(H_2O_2)/g(COD),pH呈弱酸性,反应时间2 h、温度30℃左右时,UV/H_2O_2工艺处理效果好。MBR反应器对UV/H_2O_2工艺段出水中有机物的生化降解效果显著,出水有机物去除率稳定在80%以上。     

Ozonation,Ozone/UV and UV/H2O2 Degradation of Chlorophenols

The performance of the O₃, O₃/UV and UV/H₂O₂ processes for degradation of six chlorophenols (4-chlorophenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol) were studied in laboratory reactors. Comparative study showed that chlorophenols can be degraded successfully by all of the methods studied, whilst traditional ozonation at high pH was determined to be the most effective method to treat chlorophenols. Even though the molar absorptivity of chlorophenols is known to be relatively high in the UV-region, the combination of UV-radiation with ozone did not accelerate the degradation of chlorophenols further. The toxicity of degradation products formed during ozonation of chlorophenols has been compared with the toxicity of pure chlorophenols utilizing Daphnia magna 24 hours test. Ozonation of chlorophenols yielded less toxic or even nontoxic products for Daphnia magna compared with parent compounds.     

TiO2／UV／O2和TiO2／UV／N2体系降解水中对氯硝基苯

以商用TiO2P25为催化剂,分别在TiO2/UV/O2和TiO2/UV/N2两种体系下进行降解对氯硝基苯(pCNB)试验.采用ESR对两种体系下光催化反应形成的.OH进行测定,利用LC-MS对两种体系下反应形成的中间产物进行了定性和定量分析,最后对pCNB降解过程中氯和硝基的存在形式进行了研究.结果表明:TiO2/UV/O2体系的催化降解效果要明显优于TiO2/UV/N2体系;两种反应体系都有.OH产生,并且TiO2/UV/O2体系产生的.OH的量多于TiO2/UV/N2体系产生的.OH的量;TiO2/UV/O2体系形成的中间产物的种类要多于TiO2/UV/N2体系形成的,苯环上的氢、氯、硝基均可被.OH取代形成对硝基酚(pNP)、5-氯-2-硝基酚(5-C-2-PN)等酚类物质;两种体系下均有Cl-和NO2-存在,其中Cl-生成势与pCNB的去除势一致,只有TiO2/UV/O2体系中存在NO3-.     

O3/UV,O3/TiO2/UV,O3/VO2/TiO2降解磺基水杨酸

实验利用O3/UV,O3/TiO2/UV,O3/VO2/TiO2降解了磺基水杨酸.结果表明,在这三种高级氧化技术中,O3/VO2/TiO2的氧化效果最好,如在相同的条件下,30 min后取样表明三者COD的去除率分别为47%,55%和70%.在不同pH条件下研究表明O3/TiO2/UV对水体pH的影响较为敏感.通过加入自由基猝灭剂研究表明三者产生羟基自由基的活性顺序是O3/VO2/TiO2＞O3/TiO2/UV＞O3/UV.     

Modeling of photooxidation of acetamide herbicides in natural waters by UV radiation and the combinations UV/H2O2 and UV/O3

The photooxidation of several herbicides belonging to the acetamides group (specifically propachlor, metolachlor and butachlor) by means of a monochromatic UV irradiation in ultrapure water was studied. In the case of propachlor, the quantum yield for its photolysis was evaluated directly, and a value 0.127 ± 0.01 mol Eins^?1 was obtained independent of the pH. The quantum yields for the photolysis of metolachlor and butachlor were determined by using a competition kinetic model which used propachlor as reference compound, and values of 0.56 ± 0.05 and 0.78 ± 0.04 mol Eins^?1 were deduced respectively for metolachlor and butachlor. In a second step, the elimination of the selected herbicides in some natural and mineral waters was studied by means of several oxidation systems: UV radiation alone, and UV radiation combined with hydrogen peroxide and ozone. The influence of the operating variables in these processes (acetamide type, presence or absence of tert‐butyl alcohol and types of waters) are discussed as a consequence of the amounts of herbicides removed. Two different kinetic studies were carried out for the oxidation of the herbicides: the first one for UV radiation alone and UV radiation combined with H₂O₂; the second one for the combination UV radiation plus ozone. In these studies, the specific rate constants were evaluated in every process. Finally, kinetic models for the prediction of the elimination of these herbicides in the natural waters selected by the different oxidation systems are proposed. The values of concentrations predicted by these models agree well with the experimental results obtained. Copyright © 2004 Society of Chemical Industry     

UV/草酸铁/H2O2法处理染料废水

采用UV/草酸铁/H2O2法处理染料废水，考察了体系中K2C2O4浓度、FeSO4浓度、H2O2浓度、pH值及反应温度对吡啰红染料废水色度去除效果的影响.结果表明，UV/草酸铁/H2O2法能有效地使染料水溶液迅速脱色，草酸铁的加入能提高脱色速率，H 2O2/FeSO4/K2C2O4的摩尔比为100：7：1时，吡啰红脱色效果最好;另外，通过测定降解过程中吸光度、电导率、pH值的变化，揭示了降解产物中无机粒子的变化规律及某些可能的产物类型。     

Photodegradation of tetracyclines in aqueous solution by using UV and UV/H2O2 oxidation processes

BACKGROUND: The objective of the present study was to analyse the kinetics of photodegradation of three antibiotics from the tetracycline group (tetracycline (TC), chlortetracycline (CTC) and oxytetracycline (OTC)), and the influence of the operational variables: (1) initial concentration; (2) initial solution pH; (3) addition of hydrogen peroxide; (4) effect of the aqueous matrix (ultrapure water (UW), surface water (SW), groundwater (GW) and waste‐water (WW) on these processes. RESULTS: The results obtained show that the photodegradation of the three tetracyclines fits first‐order kinetics. The degradation rate depends on initial concentration and pH. Low concentrations of H₂O₂ markedly increased the efficacy of TC photolysis, with a linear relationship between degradation rate and H₂O₂ concentration for concentrations of 2 × 10^?2 to 2 × 10^?1 mmol L^?1. The photodegradation rate is higher in real waters than in ultrapure water. The toxicity of oxidation by‐products formed during tetracyclines photooxidation process was determined by a bioluminescent test, showing that toxicity increases during the process. CONCLUSIONS: Oxidation of tetracyclines by UV radiation alone is slow due to the low quantum yield determined. The UV/H₂O₂ process is an interesting alternative to oxidise tetracyclines in aqueous solution, because this process decreases total organic carbon concentration and tetracyclines oxidation by‐products toxicity. Copyright © 2010 Society of Chemical Industry     

UV/H2O2/草酸铁络合物处理水中聚丙烯酰胺

采用UV/H2O2/草酸铁作为氧化剂氧化降解水中的聚丙烯酰胺(PAM)。研究了H2O2投加量、反应时间、n(Fe3+):n(草酸)对PAM降解的影响。试验结果表明,在室温25℃,n(Fe3+):n(草酸)=1:3,H2O2浓度为15 mmol.L-1,pH=3的条件下,光照120 min后,质量浓度为400 mg.L-1的PAM的去除率达到88.3%,与其它光氧化体系相比,去除效果较为明显。     

Evaluation of Degradation Characteristics of Reactive Dyes by UV/Fenton,UV/Fenton/Activated Charcoal,and UV/Fenton/TiO2 Processes: A Comparative Study

The photochemical decolorization and mineralization of Reactive red 241 (RR241) in aqueous solution has been studied using a homogeneous photofenton process and its combination with activated charcoal and titanium dioxide. The effects of applied catalyst and adsorbent loading, dye concentrations, pH of solution, and the effect of various systems at constant UV irradiation were determined. Decolorization, COD and TOC analysis were employed to evaluate the results of the photochemical and photocatalytic degradation of RR241. The degradation of the dye was monitored by constant COD analysis and then analyzed by high performance liquid chromatography (HPLC) and IR analysis. The result shows that complete decolorization of dye with photofenton process required 240 minutes with 18.6% of maximum TOC reduction. To overcome the problem of slow decolorization and low degradation with photofenton process, it was combines with activated charcoal and Titanium dioxide. UV/Fenton/AC process gave complete decolorization in less than 80 minutes with 14.9% of TOC reduction after 240 minutes. In contrast the UV/Fenton/TiO₂ process required 120 minutes for complete decolorization but yielded maximum TOC reduction of 43.9% after 240 minutes. Therefore, according to COD and TOC reduction it could be suggested that the UV/Fenton/TiO₂ was more effective than other processes.     

Degradation of Sulfosalicylic Acid by O3/UV O3/TiO2/UV,and O3/V-O/TiO2 : A Comparative Study

Chemical oxygen demand (COD) removal rates of sulfosalicylic acid (SSal) degraded by three advanced oxidation processes (AOPs): O₃/UV, O₃/TiO₂/UV and O₃/V-O/TiO₂ are compared in this paper. (V = Vanadium). The results show that O₃/V-O/TiO₂ is the most effective process among three AOPs and the order of degradation efficiencies at different pH values is shown as O₃/V-O/TiO₂ > O₃/TiO₂/UV > O₃/UV. For example, at the buffered solution of pH 6.8, the COD removal rate of O₃/V-O/TiO₂ reaches 70% in 30 minutes, but those of O₃/TiO₂/UV and O₃/UV are 55% and 47% at the same conditions, respectively. Furthermore, the effect of CO₃ ^{2 ?}on the COD removal rates of three AOPs shows that O₃/V-O/TiO₂ and O₃/TiO₂/UV may be considerable promising methods to overcome the limitation of the presence of radical scavenger in solution. Both the adsorption of SSal on catalysts and other oxidants (atom oxygen, photo-generated hole) must be responsible for the above result.