臭氧氧化法及其联合技术在废水处理中的应用

臭氧具有极强的氧化能力,其反应产生的物质一般对环境污染很小。综述了臭氧处理单元的几种方式、臭氧联合技术及其在处理城市污水及工业污水中的应用,并概述了臭氧氧化技术的发展现状及趋势。     

在空气中杀菌灯产生臭氧及其催化分解的研究

用流动型反应装置,对8W杀菌灯(主波长λ=253.7nm)辐照空气时产生的臭氧进行了研究.发现在一定条件下当空气与杀菌灯接触大约7s时,就有超出0.33μg/L的臭氧产生.随着空气流速的减小,产生的臭氧的量随之变大.采用臭氧分解催化剂对臭氧的消除进行了研究,当体积空速小于1.1×10⁵h^-1时,臭氧可以降解到安全范围.     

非均相催化臭氧氧化反应机制

臭氧催化氧化作为高级氧化技术是目前水处理领域研究的热点,其中非均相臭氧催化氧化技术因其氧化能力强、降低臭氧投加量特别是能显著提高有机物矿化率等优点而备受关注。非均相催化臭氧氧化领域不断研究新的催化剂,但是其反应过程及机制更加复杂。催化臭氧氧化的性能很大程度上取决于催化剂及其表面性质。污染物在催化剂表面形成络合物,或者臭氧在催化剂表面分解产生不同的含氧物种如表面氧原子、过氧化物和羟基自由基等。本文评述了非均相臭氧催化氧化反应中存在的多种机理,主要是自由基理论、氧空位理论、表面原子氧理论、表面络合物理论和臭氧直接氧化理论。催化剂表面的羟基基团是主要的催化活性中心,本文探讨了表面羟基基团催化反应机制,得出催化剂表面性质决定其表面活性位点的特性及含量,对诱导臭氧分解产生含氧活性物种起了关键作用;概述了催化剂改性后的结构形态、比表面积及其性能和作用机制;并讨论了非均相臭氧催化氧化反应催化剂未来的发展趋势,为催化臭氧氧化污水处理技术提供了理论参考。     

臭氧消毒简介

臭氧是公认的广谱、高效杀菌剂。介绍了臭氧消毒的特点、原理,臭氧的产生方法,臭氧消毒的应用等。     

珠江三角洲夏季臭氧区域污染及其控制因素分析

2006年夏季,在珠江三角洲(简称珠三角)开展了一次大型野外综合空气质量观测实验.实验包括了珠三角现有的环境监测网络和两个额外设置的超级观测站.本文基于环境监测网络的观测结果对区域臭氧污染状况和污染过程进行了分析,对各站点所记录的气团光化学属性进行了诊断.结果发现,两个超级站点分别对应着污染城市地区和下风向远郊区的光化学条件,它们较好地覆盖了区域尺度上主要的臭氧高值区.使用基于观测的模型对超级站上臭氧的光化学产生过程及臭氧控制区进行了分析.结果显示,第一,模式中的醛类化学和缺失的HONO化学对于臭氧光化学产生具有重要影响;第二,在城市地区,臭氧的光化学产生速率主要受人为源排放碳氢化合物控制;而在城市远郊区,臭氧的光化学产生速率主要受NO控制;第三,重要的人为源排放的碳氢化合物是烯烃和芳香烃.使用O′x和NOz的回归结果对臭氧产生效率进行了估算,发现城市和郊区的数值存在显著差异(分别为2.1和7.8),这从侧面支持了模型对于城市和郊区臭氧控制区属性的判断.     

紫外吸光光度法直接测定水中臭氧

臭氧是一种广谱杀菌剂 ,可杀灭细菌繁殖体和芽胞 ,病毒 ,真菌等 ,并可破坏肉毒杆菌毒素 ,臭氧发生器应用于饮水消毒 ,在一些先进国家已普及使用。国内目前正处于研制试用阶段。对于用臭氧发生器在水中产生的臭氧测定研究 ,国内未见报道。本文研究了臭氧发生器 ,紫外吸光光度法 ,将臭氧发生器在水中产生的臭氧 ,用含有 2 %碘化钾的 0 .2ｍｏｌ·Ｌ-1硼酸溶液吸收液置换出碘 ,比色定量。直接测定水中的臭氧。该法快速、灵敏 ,结果满意。1　试验部分1 .1　仪器与试剂μ3 0 0 0 紫外分光光度计臭氧发生器吸收液 :2 0 ｇ·Ｌ-1碘化钾的 0 .2ｍｏ…     

气相滴定在臭氧计量标准溯源中的应用

利用臭氧和一氧化氮发生快速反应生成二氧化氮的原理,设计气相滴定反应系统,通过对参加反应的一氧化氮标准气体浓度变化的准确测定,计算出组分臭氧混合气体的浓度。利用设计的气相滴定系统（GPT）,对基于紫外分光原理的臭氧测量标准装置SRP41产生的空气中臭氧标准气体进行了比对及相互验证。比对结果表明：二者偏差不大于2．6％,均在分析不确定度范围内等效。这为臭氧测量计量溯源问题提供了解决方案。     

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。     

北京地区臭氧污染的来源分析

光化学烟雾污染是影响北京地区夏季空气质量的一个重要环境问题．利用区域空气质量模（CAMx）对2000年6月底至7月初发生在北京地区的臭氧污染过程进行模拟,运用臭氧源识别技术（OSAT）和地区臭氧评估技术（GOAT）,量化了不同地区的污染源排放对北京市城近郊区臭氧污染的贡献,探讨了周边地区排放的臭氧贡献方式问题,分析了北京地区臭氧污染的化学机制特征．研究表明,北京地区臭氧污染分布存在显著差异,并且具有明显的区域性特征,定陵地区的超标臭氧主要受到城近郊区烟羽的严重影响（占55％）,城近郊区则除了受到北京市的前体物排放影响外（占46％）,来自天津市、河北省南部地区的贡献往往也占有重要份额;周边地区对北京市城近郊区的贡献中,直接输入的臭氧约占七层,其余部分以输入前体物的方式贡献臭氧;北京城近郊区的臭氧生成主要受挥发性有机物控制,而在远郊区县和农村地区臭氧生成对氮氧化物变得更为敏感．对北京地区臭氧污染的源排放控制,需要综合考虑各种臭氧来源和不同贡献方式的重要性,以及臭氧生成机制的变化规律．     

大气臭氧化学研究进展

臭氧是大气化学中的核心物种。在平流层中，臭氧层可以吸收对生物有害的紫外辐射，对地球生命起保护伞作用。在对流层大气中，适量臭氧对清洁大气是有益的。但是，由于对流层中臭氧前体物排放量的增加，特别是在大城市，产生的高浓度臭氧会对大气环境造成严重污染，对人类、动植物和生态环境具有极大危害。臭氧的研究一般结合外场观测、实验室烟雾箱模拟和计算机数值模拟进行。深入开展大气臭氧化学研究，不仅有助于全面深入理解大气氧化过程以及全面掌握区域乃至全球大气自净能力，而且能为对流层污染控制提供科学依据和方案。本文总结了近年来有关臭氧化学的研究进展，论述了臭氧问题与人类当前面临的一些主要环境问题间的相互关系；重点综述了近年来有关南极臭氧空洞、中纬度地区臭氧低值和北极地区臭氧的损耗机理及其发展趋势；综述了臭氧与大气光化学和气溶胶间的耦合关系，并结合我国实际情况，提出了大气臭氧化学尚待深入开展研究的一些重要科学问题。     

An Ozone Generator of Miniaturization and Modularization with the Narrow Discharge Gap

The method of ionization discharge has a key action on the process of the ionization and decomposition of O₂ molecule as well as the re-decomposition of O₃ molecule. In this paper, an ozone generation of miniaturization which was fabricated by stacking discharge modules with rectangle is introduced, only volume of 23.0×53.0×42.0 cm³ for ozone production capacity of 1 kg/hr. In addition, the ozone concentration and its production efficiency are significantly improved in comparison with a conventional ozone generator, which have the highest ozone concentration of 308 g/Nm³ and the production efficiency of 118 g/kWh at ozone concentration of 200 g/Nm³.     

New suggestion for electronic structure of the ground state of ozone

Determination of electronic structure of ozone related geometry is the main subject in this research. The proposed electronic structure must satisfy the experimental geometry, explain the excellent oxidizing properties of ozone, and can also explain the capability of additional reaction with unsaturated hydrocarbons. The potential energy surface of singlet and triplet state of ozone has been studied in order to check the correctness of the proposed structure. The proposed electronic structure of ozone is capable of explaining the oxidizing behavior of ozone in visible wavelength (daylight) 430–700 nm. For comparison, the other proposed structure of ozone in literature such as Pauling, Linnett and Weinhold has also been discussed. The main method used in this research is well-known density functional procedure, B3LYP, which takes the electron correlation aspect into consideration. The polarization and diffused functions are included in the basis set, 6-311++G**. The obtained geometry is a bent and cumulated double bond with inter-bond angle 118.42° (1.39%), and bond length 1.256 Å (1.72%). The obtained results revealed that frontier orbital theory is a proper tool for explaining the addition reaction.     

氧化领域的“姐妹花”:氧气和臭氧

概述了氧气与臭氧这对同素异形体的发现过程、结构及应用情况,其中重点介绍了氧气在催化氧化醇方面的应用和臭氧在催化氧化废水中有机污染物方面的应用,发现2者具有共同的氧化特点,均是依赖产生含氧活性物种来加快氧化反应的进行;同时发现由于2者结构的不同,导致催化剂在其各自所参与的催化氧化过程中发挥的作用不同。     

Dynamics and mechanism of the interaction of graphite powders with ozone

The kinetics of ozone sorption by powders of finely milled graphite at 20 °C, the behavior of unpaired electrons of the conjugated systems of the structure, and the IR spectra of the surface functional groups were studied. The surface hexagonal cells enter into the reaction. After 1/6 of the accessible cells was consumed, the reaction rate decreased appreciably, most likely, due to the induction effects of the functional groups formed. Considerable weight losses of the samples were observed during the reaction. The changes in the character of the ESR spectra indicate a decrease in the sizes of the conjugation ensembles. The reaction of ozone with the surface produces local sites of structure destruction, which decrease the reactivity of the adjacent surface regions and thus protect them from further destruction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1772–1776, September, 2008.     

The mechanism and pathway of the ozonation of 4-chlorophenol in aqueous solution

Chlorophenols (CPs) have been widely used in dif- ferent formulations as preservatives, herbicides, insec- ticides, bactericides and solvents. Parts of chlorophe- nols were released to the natural environment during the usage. As a result, many water sources were con- taminated with CPs[1,2]. Furthermore, they also can be formed during the disinfection of phenol containing water by chlorination. Several CPs are recognized as the priority pollutants by the United States EPA (En- vironmenta…     

Ozone Degradation by Fluoride onto Plasma-Treated Activated Carbon in CF4

The ozone degradation of fluorine was investigated using the tetrafluoromethane plasma-treated activated carbon (PT-AC). The ozone in the stratosphere has been degraded by the chloride and bromide radicals which are produced from chlorofluorocarbons and bromofluorocarbons, respectively. However, we believe that fluorine also was related to the ozone degradation. The fluoride was introduced onto the activated carbon surface by tetrafluoromethane plasma treatment. The breakthrough curve of ozone onto PT-AC was measured to elucidate the relationship between the ozone and the fluoride. The amount of ozone adsorbed/degraded onto the PT-AC was larger than the amount that was adsorbed/degraded onto the untreated activated carbon. The amount of fluoride ion eluted from the PT-AC before the adsorption/degradation of ozone was larger than that which eluted after the adsorption/degradation of ozone. These results indicated that the ozone was degraded by the fluoride on the PT-AC surface.     

Ozone Production in the Positive DC Corona Discharge: Model and Comparison to Experiments

A numerical model of ozone generation in clean, dry air by positive DC corona discharges from a thin wire is presented. The model combines the physical processes in the corona discharge with the chemistry of ozone formation and destruction in the air stream. The distributions of ozone and nitrogen oxides are obtained in the neighborhood of the corona discharge wire. The model is validated with previously published experimental data. About 80% of the ozone produced is attributed to the presence of excited nitrogen and oxygen molecules. A parametric study reveals the effects of linear current density (0.1–100 A/cm of wire), wire radius (10–1000 m), temperature (300–800 K) and air velocity (0.05–2 m/s) on the production of ozone. The rate of ozone production increases with increasing current and wire size and decreases with increasing temperature. The air velocity affects the distribution of ozone, but does not affect the rate of production.     

双金属核壳结构负载型Au@Ag/TiO2催化剂的制备及表征

利用溶胶法制备了Au核Ag壳(Au@Ag)结构复合纳米粒子,用粉末-溶胶法和水热合成法使其负载于TiO₂纳米粒子上,利用紫外-可见吸收光谱﹑X射线粉末衍射﹑透射电子显微镜对复合结构材料进行了结构表征,并对其光催化消除臭氧的性能进行了研究。结果表明,制备方法、Au/Ag化学计量比及金属负载量等对光催化消除臭氧的活性均有很大影响。采用粉末-溶胶法制备的1%-Au@Ag/TiO₂(n_Au/n_Ag=1∶3)催化剂,由于TiO₂表面沉积的Au@Ag金属颗粒尺寸小且分散度高,而且1%的金属担载量有利于光生电子空穴的有效分离,光催化消除臭氧的活性最高。