溶液中阴离子和腐殖酸对UV/H2O2降解2,4-二氯酚的影响

研究了UV/H2O2工艺对2,4-二氯酚(2,4-DCP)的去除效果和水中阴离子、腐殖酸对该工艺降解2,4-DCP的影响.结果表明:UV/H2O2工艺可以有效地去除水中2,4-DCP,光降解过程符合一级反应动力学模型;在H2O2投加量为8 mg/L、1个30 W低压汞灯照射下,2,4-DCP在蒸馏水和自来水中反应速率常数分别为0.023 2、0.016 2 min-1;NO-3、Cl-、HCO-3对2,4-DCP光降解有抑制作用,当3种阴离子摩尔浓度为0.5、10.0、20.0 mmol/L时,对2,4-DCP光降解的抑制程度为HCO-3＞NO-3＞Cl-;腐殖酸在低浓度时,促进光降解反应进行,在高浓度时,2,4-DCP的光降解受到抑制.自来水中的反应速率常数低于蒸馏水中的反应速率常数是由于水中多种阴离子和腐殖酸影响的结果.     

UV/H2O2联合氧化法去除畜禽养殖废水中抗生素

随着畜禽养殖业的迅猛发展,畜禽养殖废水污染问题日益突出,尤其是养殖过程中大量使用抗生素,致使畜禽养殖废水含有抗生素,成为一类新型环境危害污染物.如何有效去除畜禽养殖废水中的抗生素,成为国内外研究热点.采用UV/H2O2联合氧化法去除畜禽养殖废水中抗生素(磺胺甲恶唑、磺胺噻唑、磺胺甲噻二唑、磺胺二甲氧嘧啶、磺胺二甲嘧啶)...     

Hydroxyl radical scavenging role of chloride and bicarbonate ions in the H2O2/UV process

Simultaneous effect of inorganic anions, such as chloride and bicarbonate ions, on the scavenging of hydroxyl radicals (HO*) in the H2O2/UV process is the focus of this paper. The model compound of n-chlorobutane (BuCl) was used as the probe of HO*. By changing the pH conditions (2-9) and the concentrations of NaCl (0.25-2500 mM) and NaHCO3 (25 mM), the variation of HO* concentrations and the rate of H2O2 decomposition were compared. In general, the BuCl and H2O2 follow closely the first-order reaction within the first 10 and 40 min, respectively. In the presence of chloride alone at the pH range of 2-6, the HO* concentration in the reaction mixture increases with the increase of pH, and the HO* concentration at pH = 6 is 100 times of that at pH = 2. Including bicarbonate species in the solution, the peak HO* concentration was found at a certain pH, which shifts from 4, 5, to 5-7, as the molar ratios of chloride/bicarbonate species increase from 1 to 100. In addition, without bicarbonate species HO* concentration decreases significantly with increasing chloride concentration but remained rather unchanged beyond 1250 mM. In contrast, the HO* scavenging in the presence of bicarbonate species became relatively significant only when the chloride concentration reached beyond 250 mM. Throughout all experiments of different water quality conditions, the H2O2 decomposition rate remains rather unchanged.     

UV/H2O2/Fe-FeOxH2x-3和UV/H2O2工艺降解水中富里酸的研究

采用硼氢化钠还原法制备核-壳结构的Fe-FeOxH2x-3复合材料,研究了富里酸在UV/H2O2和UV/H2O2/Fe-FeOxH2x-3两种不同反应体系下的降解情况。结果表明,核-壳结构Fe-FeOxH2x-3的存在,提高了UV/H2O2降解富里酸的反应速率,TOC去除达到84%。采用XAD树脂吸附法对反应前后的富里酸进行化学分级表征,结果表明,富里酸经反应后憎水酸（HoA）、弱憎水酸（WHoA）和憎水中性物质（HoN）都有所减少,进而转化为亲水性物质（HiM）;用超滤膜法对富里酸进行物理分级表征,考察了富里酸在反应前后分子量分布的变化情况。同时,富里酸经过反应后生成的中间产物降低了三氯甲烷生成趋势。     

溶液中阴离子对UV/H2O2降解十二烷基苯磺酸钠的影响及其机理

研究了UV/H2O2工艺对十二烷基苯磺酸钠(LAS)的去除效果、溶液中阴离子对LAS降解的影响及机理.结果表明:UV/H2O2工艺可以有效地去除水中的LAS;在H2O2投加量为8 mg/L,14 W低压汞灯照射下,LAS在蒸馏水和自来水中的反应速率常数分别为0.018 0 、0.012 2 min-1;NO-3、Cl-、SO2-4和HCO-3对LAS光降解有抑制作用,当该4种离子摩尔浓度均分别为5、10、15 mmol/L时,对LAS光降解的抑制程度为HCO-3》NO-3》Cl-》SO2-4,且随着离子摩尔浓度的增大,抑制作用增强;LAS在自来水中的反应速率常数低于在蒸馏水中的反应速率常数是由于水中多种离子影响的结果.     

Comparative study of the formation of brominated disinfection byproducts in UV/persulfate and UV/H2O2 oxidation processes in the presence of bromide

Environmental Science and Pollution Research - The objective of this research was to compare the transformation of Br? and formation of brominated byproducts in UV/persulfate (PS) and UV/H2O2...     

Oxidation of MCPA and 2,4-D by UV radiation, ozone, and the combinations UV/H2O2 and O3/H2O2

The phenoxyalkyl acid derivative herbicides MCPA (4-chloro 2-methylphenoxyacetic acid) and 2,4-D (2,4-dichlorophenoxyacetic acid) were oxidized in ultrapure water by means of a monochromatic UV irradiation and by ozone, as well as by the combinations UV/H2O2 and O3/H2O2. In the direct photolysis of MCPA, the quantum yield at 20 degrees C was directly evaluated and a value of 0.150 mol Eins(-1) was obtained in the pH range 5-9, while a lower value of 0.41 x 10(-2) mol Eins(-1) was determined at pH=3. Similarly, for 2,4-D a value of 0.81 x 10(-2) mol Eins(-1) was deduced, independent of the pH of work. The influence of the additional presence of hydrogen peroxide was established in the combined process UV/H2O2, and the specific contribution of the radical pathway to the global photo-degradation was evaluated. The oxidation by ozone and by the combination O3/H2O2 was also studied, with the determination of the rate constants for the reactions of both herbicides with ozone and hydroxyl radicals at 20 degrees C. These rate constants for the direct reactions with ozone were 47.7 and 21.9 M(-1) s(-1) for MCPA and 2,4-D respectively, while the found values for the rate constants corresponding to the radical reactions were 6.6 x 10(9) and 5.1 x 10(9) M(-1) s(-1).     

Degradation of bisphenol A using UV and UV/H2O2 processes

Bisphenol A (BPA; 4-[2-(4-hydroxyphenyl)propan-2-yl]phenol) is a substance typically used in the plastic industry. It is used in the production of epoxy resins, polycarbonate, or fire retardants or as a stabilizer and an antioxidant in numerous types of plastics. Bisphenol A is introduced into the environment via municipal and industrial wastewater. Because of its hydrophobic properties, BPA has the potential for sorption on activated sludge during the biological wastewater treatment processes. This study investigated the degradation of BPA by means of UV-radiation and in the UV/H2O2 process with the presence and absence of hydrocarbonate ions (HCO3(-)) as hydroxyl radicals (OH*) scavengers. The calculated value of quantum yield was equal to 0.18, and the value of BPA rate constant with hydroxyl radicals was equal to 3.3 x 10(9) M(-1) s(-1).     

UV/H2O2工艺降解环丙沙星的研究

采用UV/H2O2工艺去除水体中的喹诺酮类抗生素环丙沙星（CIP）。考察了溶液pH值、H2O2投加量以及水体基质对环丙沙星降解效率的影响,分析了降解产物的生成情况。研究表明,环丙沙星的降解符合拟一级反应动力学模型。降解速率受溶液pH值的影响,酸性及中性条件,有利于环丙沙星的降解。H2O2投加量的增大,使得降解速率逐渐增大,但速率增幅逐渐变缓;最佳H2O2/环丙沙星摩尔比为2 000。实际水体中存在的NOM、NO3-,促进了单独UV作用下,环丙沙星的降解。水体中的.OH焠灭剂,抑制了UV/H2O2联合作用下,环丙沙星的降解;实际水体中的光解速率常数低于超纯水中的光解速率常数。GC-MS分析表明,UV/H2O2工艺,使环丙沙星氧化降解生成氨基乙酸、丙二酸、丙三醇和对苯二甲酸等小分子有机物。     

TiO2/H2O2/UV和TiO2/O3/UV降解对氯苯甲酸和喹啉的试验研究

主要叙述TiO2/H2O2/UV和TiO2/O3/UV体系降解对氯苯甲酸(4-CBA)和喹啉的试验研究.研究表明,(1)在TiO2/H2O2/UV体系里目标物降解速度先随过氧化氢投加量的增加而提高,但超过一定浓度之后便开始下降;(2)在TiO2/O3/UV体系中,目标降解物的反应速度都非常快,且臭氧浓度高的时候降解速度更快;(3)二氧化钛催化剂在TiO2/O3/UV体系中作为积极因素有助于提高反应速率,而在TiO2/H2O2/UV体系是消极因素,会降低反应速率.     

TiO2/H2O2/UV和TiO2/O3/UV降解对氯苯甲酸和喹啉的试验研究

主要叙述TiO2/H2O2/UV和TiO2/O3/UV体系降解对氯苯甲酸（4-CBA）和喹啉的试验研究.研究表明,（1）在TiO2/H2O2/UV体系里目标物降解速度先随过氧化氢投加量的增加而提高,但超过一定浓度之后便开始下降;（2）在TiO2/O3/UV体系中,目标降解物的反应速度都非常快,且臭氧浓度高的时候降解速度更快;（3）二氧化钛催化剂在TiO2/O3/UV体系中作为积极因素有助于提高反应速率,而在TiO2/H2O2/UV体系是消极因素,会降低反应速率.     

O3/H2O2/UV降解1,2,4-三氯苯的研究

采用O3/H2O2/UV工艺处理1,2,4-三氯苯(TCB)模拟废水,考察了TCB初始浓度、pH、H2O2投加量及O3转化率等因素对O3/H2O2/UV降解TCB的影响,推断了TCB可能的降解途径。结果表明:(1)H2O2、O3、UV、O3/H2O2、O3/H2O2/UV 5种体系对TCB的降解效果为H2O2相似文献   

UV/草酸铁/H2O2法处理乙草胺废水的研究

对UV/草酸铁/H2O2法处理乙草胺废水进行研究,考察了H2O2浓度、FeSO4浓度、K2C2O4浓度、pH值及反应时间对乙草胺去除效果的影响.结果表明,当H2O2/FeSO4/K2C2O4(化学剂量数比)=5051,H2O2/乙草胺初始COD(质量浓度比)=31时,该技术对乙草胺的去除率可达85%以上.这表明,采用UV/草酸铁/H2O2法可以有效地处理含乙草胺废水.     

Characterization of the humic material formed by composting of domestic and industrial biowastes Part 1. HPLC of the cupric oxide oxidation products from humic acids

The changes induced by humification of anaerobically digested sewage sludge, source separated biowaste, and pulp mill biosludge were determined by extracting the fractions of bitumen and humic and fulvic acids from the samples of fresh and humified composts. In all cases, a distinct decrease in the amount of bitumen could be detected during humification. The amount of humic acids increased in sewage sludge and biowaste samples, but decreased in pulp mill biosludge sample during humification. The humic acids were degraded by CuO oxidation and the phenolic degradation products were analysed by reversed-phase high-performance liquid chromatography. The yield of these aromatic degradation products was in the range 0.9–2.0 % for each sample. The main phenolic degradation products were 4-hydroxybenzoic acid, vanillic acid, 4-hydroxybenzaldehyde, vanillin, syringaldehyde, and acetovanillone. Two lignin dimers, dehydrodivanillin and dehydrodiacetovanillone, were also identified.     

臭氧/双氧水/紫外光联用降解饮用水中溴氯乙腈的试验研究

为减少饮用水氯化消毒过程中产生的含氮消毒副产物溴氯乙腈(BCAN),降低其潜在的致癌风险,分别采用臭氧(O3)、双氧水(H2O2)和紫外光(UV)及其联合工艺,考察了不同试验条件下BCAN的降解效果及影响因素,并探讨了其降解机制和动力学规律。结果表明,O3、H2O2和UV工艺对BCAN降解效果都不理想,UV/H2O2和UV/H2O2/O3联合工艺可以较有效地降解水中的BCAN。在BCAN初始质量浓度为20μg/L、紫外光强为31μW/cm2、H2O2质量浓度为40 mg/L、O3质量浓度为7.9mg/L条件下,反应进行120min后,UV/H2O2联合工艺与UV/H2O2/O3联合工艺对BCAN的降解率分别为77.50%、94.05%。UV/H2O2/O3联合工艺对BCAN的降解效果比UV/H2O2联合工艺更好,UV/H2O2和UV/H2O2/O3联合工艺降解BCAN均符合一级反应动力学规律。     

UV/H2O2/草酸铁络合物光降解邻苯二甲酸二丁酯研究

研究了邻苯二甲酸二丁酯(DBP)在UV/H2O2/草酸铁络合物体系中的光降解.结果表明,UV/H2O2/草酸铁络合物能有效地光解DBP;在pH值为4时,DBP光解速率最快,中性和碱性条件下光解效率降低;DBP的光解速率随H2O2浓度的升高而增大,但H2O2浓度较大时,其对·OH的清除作用使DBP的光解速率减慢;[Fe3 ]/[C2O42]＜1/10,DBP光解速率随Fe3 浓度增大明显提高,[Fe3 ]/[C2O42]＞1/10时,引起DBP光解速率的增加不明显.     

O3、H2O2／O3及UV／O3在焦化废水深度处理中的应用

采用O3、H2O2／O3及UV／O3等高级氧化技术（AOPs）对某焦化公司的生化出水进行深度处理,考察了O3与废水的接触时间、溶液pH、反应温度等因素对废水COD去除率的影响,确定出O3氧化反应的最佳工艺参数为：接触时间40min,溶液pH8．5,反应温度25℃,此条件下废水COD及UV254的去除率最高可达47．14％和73．47％;H2O2／O3及UV／O3两种组合工艺对焦化废水COD及UV254的去除率均有一定程度的提高,但H2O2／O3系统的运行效果取决于H2O2的投加量。研究结论表明,单纯采用COD作为评价指标,并不能准确反映出O3系列AOPs对焦化废水中有机污染物的降解作用。     

UV/H2O2协同光降解处理酒石酸镍废水

含镍电镀废水中酒石酸的存在,使得废水中总镍无法通过化学沉淀法去除,无法满足达标排放要求。采用UV/H2O2光降解法处理酒石酸镍体系废水,考察了不同反应pH值、过氧化氢投加量、光照时间对酒石酸镍体系络合废水的处理效果。实验结果表明：UV/H2O2法对酒石酸镍体系废水有很好的协同处理效果,光降解过程呈拟一级动力学过程;优化的酒石酸镍废水处理工艺为反应pH值3.0,30%过氧化氢投加量2 mL·L-1,15 W功率紫外灯光照下反应120 min,在优化的工艺条件下,采用化学沉淀法去除水中镍,处理后电镀废水中总镍可满足《电镀污染物排放标准》（GB 21900-2008）中0.5 mg·L-1要求。