二氧化氯制备方法研究进展

二氧化氯是一种具有高氧化性和强消毒性的化合物,本论文介绍了二氧化氯制备的化学法、电解法以及电化学法,并对几种工艺方法的优缺点进行了分析和比较,适合工业化生产的工艺主要是化学法中的氯酸钠法和亚氯酸钠法。     

二氧化氯制备方法研究进展

二氧化氯是一种具有高氧化性和强消毒性的化合物,介绍了二氧化氯制备的化学法、电解法以及电化学法,并对几种工艺方法的优缺点进行了分析和比较,适合工业化生产的工艺主要是化学法中的氯酸钠法和亚氯酸钠法。     

负压二次曝气二氧化氯发生器的研制与应用

以氯酸钠和工业盐酸为基本原料,采用独特的负压二次曝气工艺,在催化剂作用下,经氧化还原反应产生以二氧化氯为主的混合消毒气体,经吸收后形成一定浓度的二氧化氯混合消毒液,与待处理水充分混合,达到杀菌消毒的目的。     

Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometric determination of chlorine dioxide in the presence of othe chlorine species,viz,free chlorine,chlorite,chlorate and hypochlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct spectrophotometric determination for chlorine dioxide owing to the serious interference of free and combined dhlorine.The procedure gave a linear calibration graph over the range0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.     

Electrolyte effects on aqueous atmospheric oxidation of sulphur dioxide by hydrogen peroxide

The rate of oxidation of sulphur dioxide by hydrogen peroxide in the presence of various supporting electrolytes has been determined by the stopped flow method. In a sodium perchlorate medium (chosen as reference electrolyte) first-order kinetics were observed with respect to HSO₃⁻, H₂O₂ and H⁺. The influence of the ionic strength was investigated and the third-order rate constant was calculated at infinite dilution. The rate constants of the reaction are shown to be far higher when chloride or ammonium ions are added to the solution.The effect of temperature and traces of metals ions (Mn²⁺, Fe²⁺, Fe³, Cu²⁺, Cr³⁺) was studied. The oxidation reaction is virtually insensitive to the effects of Mn²⁺, Fe³⁺, Cu²⁺ and Cr³⁺. Catalytic activity is observed with Fe²⁺.     

Removal of benzene homologous compounds with chlorine dioxide

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过氧化氢-敏化剂强化污泥微波预处理溶胞效果的研究

提高污泥溶胞效率是强化污泥厌氧处理的关键.为加强污泥微波预处理溶胞效果,本研究分别考察了常压、半封闭条件下二氧化钛颗粒、碳质材料作为敏化剂与过氧化氢联合进行微波污泥预处理的效果.结果表明,碳质材料敏化剂对微波、过氧化氢-微波污泥预处理产生了负作用,降低了污泥的溶胞效果,而二氧化钛能有效增加污泥中营养物质的释放.当二氧化钛颗粒投加量为0.12 g·g~(-1)干污泥时,SCOD、PO_4~(3-)-P的浓度比单独微波处理分别增加了11.86%、61%;当二氧化钛颗粒投加量为0.24 g·g~(-1)干污泥时,NH_4~+-N释放比单独微波处理高出27.78%.微波辐射作用下投加二氧化钛颗粒产生了羟基自由基,强化了过氧化氢-微波对污泥细胞的氧化作用.     

Enhanced cyanogen chloride formation after UV/PS and UV/H2O2 pre-oxidation and chlorination in natural river water

Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H₂O₂) have attracted much attention in recent years as advanced oxidation processes for water treatment. However, it is not all clear how these two methods affect the formation of cyanogen chloride (CNCl) in the subsequent water chlorination process. In this study, it was found that both UV/H₂O₂ and UV/PS pre-oxidation promoted the formation of CNCl in six actual water samples collected from urban rivers. Glycine, uric acid, arginine and histidine were investigated as the model compounds to explore the effects of different methods on the production of CNCl. The results showed that compared with chlorination alone, pre-oxidation by UV/H₂O₂ and UV/PS can reduce the production of CNCl for glycine and uric acid by up to 95% during post-chlorination process. However, they can greatly promote the formation of CNCl for arginine and histidine by up to 120-fold. In a more detailed investigation, pre-oxidation of histidine formed highly reactive intermediates to chlorine, leading to increased CNCl formation and chlorine consumption. The results showed that the precursors of CNCl was altered after pre-oxidation, and need to be re-evaluated.     

几种消毒剂对自来水中“红虫”的杀灭效果比较

为筛选出有效、安全、经济的杀灭红虫药剂,以保证居民饮用水安全,研究了氯胺、二氧化氯、次氯酸钠和过氧化氢,在20℃、无光照条件下对该种红虫单一和联合的杀灭效果。结果表明,所用消毒剂在一定剂量下(次氯酸钠4.0mg/L、氯胺>4.0mg/L、二氧化氯8.0mg/L和过氧化氢0.01%)都能在短时间内(2h)取得较好的杀灭效果。次氯酸钠、二氧化氯和过氧化氢之间对红虫的杀灭存在拮抗作用。从保证居民饮用水质量和实际的可操作性角度出发,认为二氧化氯是一种较理想的杀虫药剂。     

化学预氧化对苏氨酸生成三氯乙醛的影响

以具有最大比三氯乙醛生成潜能(SCHFP)的苏氨酸为研究对象,分析了次氯酸钠(NaClO)、二氧化氯(ClO_2)、高锰酸钾(KMnO_4)、过氧化氢(H_2O_2)、臭氧(O_3)和臭氧过氧化氢(O_3/H_2O_2)等预氧化剂对三氯乙醛(CH)生成的影响,以确定合适的预氧化剂及其适宜投加量,为CH的控制提供指导.结果表明,能够有效去除一天CH生成量(CH1d)的预氧化方式依次为H_2O_2、ClO_2、KMnO_4和NaClO,适宜投加量分别为3、0.5、0.6和0.5mg·L-1,对CH1d相应的去除率分别为61.54%、47.63%、29.77%和10.94%;能够有效去除CH生成潜能(CHFP)的预氧化方式依次为KMnO_4、NaClO、H_2O_2和ClO_2,适宜投加量分别为0.6、0.5、3和0.5mg·L~(-1),对CHFP相应的去除率分别为41.01%、33.38%、8.36%和2.40%;O_3和O_3/H_2O_2预氧化能够使CH1d和CHFP增加,不适用于对CH的控制.     

微污染水源水ClO2消毒中ClO-2的来源与控制技术

综述了ClO2消毒微污染水源水的主要无机副产物ClO2-的来源,ClO2-的产生前控制和生成后去除等方法,以减少ClO2-在饮用水中的含量。并提出了氯气氧化控制饮用水中ClO2-含量的新方法。     

Impact of combining chlorine dioxide and chlorine on DBP formation in simulated indoor swimming pools

The main objective of this study was to assess the combined use of chlorine dioxide (ClO2) and chlorine (Cl2) on the speciation and kinetics of disinfection by-product (DBP) formation in swimming pools using synthetic pool waters prepared with a body fluid analog (BFA) and/or fresh natural water. At 1:25 (mass ratio) of ClO2 to Cl2, there was no significant reduction in the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) for both BFA solution and natural water compared to the application of Cl2 alone. When the mass ratio of ClO2 to Cl2 increased to 1:1, substantial decreases in both THMs and HAAs were observed in the natural water, while there was almost no change of DBP formations in the BFA solution. Haloacetonitriles and halonitromethanes levels in both water matrices remained similar. In the presence of bromide, the overall DBP formation increased in both BFA solution and natural water. For the DBP formation kinetics, after 72 hr of contact time, very low formation of THMs and HAAs was observed for the use of ClO2 only. Compared to Cl2 control, however, applying the 1:1 mixture of ClO2/Cl2 reduced THMs by > 60% and HAAs by > 50%. Chlorite was maintained below 1.0 mg/L, while the formation of chlorate significantly increased over the reaction time. Finally, in a bench-scale indoor pool experiment, applying ClO2 and Cl2 simultaneously produced less THMs compared to Cl2 control and kept chlorite at < 0.4 mg/L, while HAAs and chlorate accumulated over 4-week operation period.     

Formation mechanism of typical aromatic sulfuric anhydrides and their potential role in atmospheric nucleation process

Sulfuric anhydrides,generated from the cycloaddition reaction of SO₃with carboxylic acids,have been revealed to be potential participants in the nucleation process of new particle formation (NPF).Hence the reaction mechanisms of typical aromatic acids (benzoic acid (BA),phenylacetic acid (PAA),phthalic acid (PA),isophthalic acid (mPA),and terephthalic acid(PTA)) with SO₃to generate the corresponding aromatic sulfuric anhydrides were investigated by density functional theory...     

二氧化氯消毒无机消毒副产物控制技术进展研究

日常生活、生产中,饮用水消毒剂受到广泛关注.中国《生活饮用水卫生标准》(GB 5749-2006)规定二氧化氯可作为饮用水消毒剂,但其在消毒过程中所产生的无机消毒副产物,对人类健康存在潜在的危害.随着检测和控制技术水平的发展,对饮用水中无机消毒副产物的研究已成为热点.文章参考大量文献,对饮用水中无机消毒副产物的控制技术进行了详细讨论.     

Photochemical degradation of nonylphenol in aqueous solution：The impact of pH and hydroxyl radical promoters

The degradation of nonylphenol (NP) in aqueous solution with UV, H₂O₂/UV, and Fenton/photo-Fenton processes was studied. The efficacy of direct and hydrogen peroxide photolysis proved to be dependent on the pH value. The addition of H₂O₂ to UV treatment improved NP degradation. The application of UV photolysis and the H₂O₂/UV system at pH 7 resulted in low pseudo first-order rate constants at 10^-4 sec^-1. In the experiments at elevated pH values the pseudo-first order rate constants increased to 10^-3 sec^-1. The efficacy of the Fenton process was lower in comparison with UV and hydrogen peroxide photolysis. The addition of UV irradiation to the H₂O₂/Fe²⁺ system substantially improved NP degradation efficacy. In terms of performance, the photo-Fenton process was similar to the H₂O₂/UV process. The most favourable process for complete nonylphenol degradation considering both operational cost and treatment efficacy was H₂O₂/UV at pH 11 and 250 mol/L H₂O₂.     

二氧化氯氧化水中苯胺的反应动力学及机理研究

采用高效液相色谱技术检测苯胺浓度随时间的变化,对二氧化氯氧化苯胺的动力学规律进行了系统的研究.结果表明,ClO₂氧化苯胺的反应对于ClO₂和苯胺均为一级反应,总反应级数为二级.在pH6.86和水温(T_w)287K条件下,二级反应速率常数k值为0.11L·(mol·s)^-1,反应活化能为73.11 kJ·mol^-1,表明ClO₂氧化苯胺的反应在一般水处理条件下即可发生.酸性和碱性条件下反应速率常数k值均较中性条件下大;亚氯酸根ClO₂^-对反应速率的影响不大CC-MS检测到对氨基酚和偶氮苯2种主要反应中间产物,文中对ClO₂氧化苯胺的反应机理进行了初步探讨.     

Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H₂O₂ is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H₂O₂. A detailed parametric study showed that the degradation rate of phenol increased with increasing [H₂O₂] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H₂O₂ oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H₂O₂ system, mainly because microwave could accelerate H₂O₂ to generate hydroxyl radical (·OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H₂O₂ process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.     

活性炭催化过氧化氢去除荧光增白剂

研究了活性炭(activated carbon,AC)吸附、改性活性炭(activated carbon modified,ACM)吸附、过氧化氢(H2O2)氧化、AC催化H2O2等方法对水体中荧光增白剂VBL的处理效果,并通过自由基俘获剂叔丁醇、催化过程气体分析等探讨了AC催化H2O2分解VBL的机制.结果表明,经硝酸铁[Fe(NO3)3]改性过的ACM对VBL的吸附去除率高于未改性的AC.活性炭催化H2O2对VBL的去除效果明显,但未改性AC催化去除率高于ACM.60 min时,AC催化氧化去除率即可达到95%以上,而ACM仅为58%.叔丁醇的加入降低了AC和ACM催化氧化对VBL的去除率,表明AC催化H2O2氧化能促进H2O2形成羟基自由基(·OH)和原子氧参与反应.AC催化H2O2分解及释放气体分析表明,AC能催化H2O2形成氧气并放热,且ACM明显快于AC.结合催化H2O2去除VBL效率的结果分析,ACM催化反应时活性中间物(自由基和原子氧等)产生速率快于AC,活性中间物自身消耗形成氧气,而不是用于分解VBL.催化反应中活性中间产物的形成速率与反应物供给速率的不匹配可能是导致ACM催化效果弱于AC的重要原因.     

UV/H2O2降解水中硝基酚及影响因素

UV/H₂O₂氧化对硝基酚实验表明,H₂O₂光解产生·OH自由基是对硝基酚降解的直接原因,12min内25mg/L的对硝基酚去除率达到98%以上.溶液中TOC变化与对硝基酚的去除并不同步,说明对硝基酚的降解中生成了一系列的中间产物,然后再达到完全矿化的.体系中H₂O₂浓度变化显示产生的中间产物对H₂O₂光解没有明显影响.研究中还对对硝基酚起始质量浓度、H₂O₂浓度及pH影响进行了考察.研究认为UV/H₂O₂是对硝基酚脱毒的一种有效方法.      

二价铁催化过氧化氢-过硫酸钠再生活性炭可行性研究

利用二价铁(Fe~(2+))催化过氧化氢(H_2O_2)-过硫酸钠(Na_2S_2O_8)双氧化体系(ICHP)对被三氯乙烯(TCE)吸附饱和的20~40目粒状活性炭(AC)进行再生研究.同时,结合扫描电子显微镜(SEM)、能量散射光谱仪(EDS)、X射线光电子能谱仪(XPS)及氮气吸附-解吸技术等手段对再生前后的AC进行表征,进一步探讨影响再生效率的原因.结果表明,AC对TCE的吸附符合准一级动力学模型,等温吸附符合Freundlich模型.在TCE∶Fe~(2+)∶H_2O_2∶S_2O_2-8=1∶9.20∶59.79∶77.52(物质的量比)的条件下,AC再生效率约为50%.研究表明,AC的炭损失、比表面积、孔隙体积及孔隙面积的减小,是再生AC吸附能力低于原状AC的主要原因.利用ICHP再生的AC可以实现对TCE的有效吸附并达到AC重复使用的目的,具有很好的实用价值.