Ozonation of Several Organic Compounds Having Low Molecular Weight under Ultraviolet Irradiation

Ozonation of several low molecular weight organic compounds under ultraviolet irradiation was studied. Nine compounds were identified as reaction products of the ozonation of phenol which was promoted by the simultaneous use of ozone and ultraviolet irradiation. In the case of several organic compounds having carbon numbers from one to six, the removal of total organic carbon (TOC) by this simultaneous use was higher than by either the ozone oxidation method or the ultraviolet irradiation method for all the compounds.     

Autoxidation of fatty materials in emulsion. III. Application of GLC and TLC to studies of the histidine-catalyzed autoxidation of methyl oleate

Methyl oleate, emulsified with sodium dodecyl-sulfate, was extensively oxidized, and the amount of oleate which was reacted was determined by GLC using methyl palmitate as an internal standard. The effects of histidine, iron, and histidine plus iron were compare with the uncatalyzed reaction in the presence and absence of ultraviolet light. Results in the absence of ultraviolet light confirmed previous findings that histidine and histidine plus iron are prooxidants at the concentration studied. In the presence of ultraviolet light the rate of oleate oxidation was about 100× faster than that of the nonirradiated reaction, and the effect of the catalysts was almost negligible. The principal products, determined by GLC and TLC, were epoxide and α,β-unsaturated carbonyl. Hydroperoxy, hydroxy, acid and aldehyde compounds were also present. Epoxy stearate, determined by GLC, compared favorably with epoxy stearate as determined by use of the Durbetaki method. Presented at the AOCS Meeting, Chicago, October 1964. E. Utiliz. Res. Dev. Div., ARS, USDA.     

Ultraviolet-Enhanced Ozonation of Organic Compounds: 1,2-Dichloroethane and Trichloroethylene as Model Substrates

1,2–Dichloroethane (DCE) and trichloroethylene (TCE) were used as model compounds to study the oxidation of organic chemicals by ozone/ultraviolet radiation, ozone, and hydrogen peroxide/ultraviolet radiation. It was found that ozone/ultraviolet radiation oxidized both 1,2–dichloroethane and trichloroethylene in batch systems, at pH = 2 (phosphate buffer). At ozone concentrations in the 1 to 5 mg/L range, the reaction was first order in both ozone and substrate. At pH = 2 and initial ozone concentration 2.2–2.6 mg/L, rate constants (k)Q = 25 and 130 M^-1sec^-1 were observed for the ozone/ultraviolet radiation oxidation of DCE and TCE, respectively. The rat e constants for ozone oxidation of DCE and TCE without ultraviolet radiation were 4.3 and 47 M^-1sec^-1, respectively.

The higher rate of TCE oxidation implies that direct reaction occurs with the double bond. Finite reaction rate of DCE with ozone, and substantial increases in rate at higher pH imply the participatation of hydroxyl radicals in the oxidation of both compounds. For example, at pH = 7, initial ozone concentration of 2.3 mg/L, the k_o for TCE oxidation by ozone/ultraviolet radiation is approximately 500 M^?1 sec^?1 almost too fast to measure in a batch system.The rate also is increased by increased ultraviolet radiation intensity, and by the presence of hydrogen peroxide, which acts as a catalyst.     

Degradation of an azo dye Orange II using a gas phase dielectric barrier discharge reactor submerged in water

A dielectric barrier discharge (DBD) system employing wastewater as one of the electrodes was applied to the degradation of an azo dye, Orange II. The main advantage of this system is that reactive species like ozone and ultraviolet (UV) light produced by the DBD can be utilized for the treatment of wastewater. This system was able to remove the chromaticity and destroy the benzene and naphthalene rings in the dye molecule effectively. The results obtained under several conditions revealed that the UV emission from the DBD reactor could enhance the degradation of the dye, particularly in the presence of titanium oxide photocatalyst. The products resulting from the destruction of the rings in the dye molecule were found to be highly recalcitrant against further oxidation to smaller molecules. The change in the initial dye concentration showed that the reaction order was around 0.8 with respect to the dye concentration. The reduction in the concentration of total organic carbon was much more efficient with oxygen than with air.     

Oxidation by UV and Ozone of Organic Contaminants Dissolved in Deionized and Raw Mains Water

Organic contaminants dissolved in deionized pretreated and raw mains water were reacted with ultraviolet light and ozone. Ozone first was used for partial oxidation followed by ozone combined with ultraviolet radiation to produce total oxidation. The reduction of TOC level and direct oxidation of halogenated compounds were measured throughout the treatment process. The rate of TOC reduction was compared for ozone injected upstream and inside the reactor.     

Effect of α-Tocopherol During In Vitro Ozonation of Methyl Linoleate: Its Implication in Ozone Therapy

Systemic ozone therapy is widely used as an oxidant therapy to treat many conditions and diseases. It is known that ozone therapy acts through a transient oxidative stress produced by lipid ozonation products. The convenience of supporting patients with antioxidants during systemic ozone therapy applications is now under discussion. We studied the reaction of linoleate (one of the main constituents of cellular membranes and plasma phospholipids) with ozone in presence or absence of α-tocopherol, in order to explore whether the combination of ozone and antioxidant has some effect on fatty acid ozonation products. Proton nuclear magnetic resonance spectroscopy (¹H NMR) was used for following the reaction between 4.8mol mmol of methyl linoleate and 2.08 or 4.32mmol of ozone, with addition of different amounts of α-tocopherol (0.10, 0.18, and 0.26μmol). Ozonide (δ=5.15ppm) and aldehydes (δ=9.63ppm and δ=9.74ppm) intensities from ¹H NMR signals markedly decreased with α-tocopherol addition. When αtocopherol is absent, the intensities from olefinic proton signals diminished with ozone concentration increment; however, with αtocopherol in the mixture a smaller decrement was achieved. No detectable signals were found with the ozonation of α-tocopherol without methyl linoleate in the reaction mixture. These results suggest that α-tocopherol reacts with those products released from the reaction of ozone with methyl linoleate. This fact points out that antioxidant supplementation during systemic ozone therapy (major and minor autohemotherapy, rectal insufflation, and so forth) can be detrimental toward achieving the needed transient oxidative stress responsible for biological activities.     

负载型纳米Au催化剂光催化性能的研究进展

金纳米颗粒对紫外和可见光有较好的吸收,能在温和条件下活化反应分子,从而促使反应发生,并提高反应物转化率和产物选择性,成为新型光催化剂的研究热点。本文介绍了纳米金催化剂的光催化反应机理,光子激发的表面等离子体共振所造成的表面电荷偶极引起亲电子或亲核反应,以及以半导体材料为载体的负载型纳米金催化剂光催化机理。总结了纳米金光催化剂在污染物和染料降解、臭氧分解、硝基化合物还原、选择氧化以及制氢等光催化领域的应用和最新研究进展,并展望了该新型光催化剂的研究发展方向。     

增粘剂对天然橡胶硫化特性及力学性能的影响

研究了增粘剂盐酸联胺和硫酸联胺对天然橡胶（NR）硫化特性及在热氧（热空气）、臭氧、光氧（紫外光）老化前后力学性能的影响。结果表明,随着盐酸联胺和硫酸联胺用量的增加,最大转矩（MH）和转矩差Δ（MH-ML）降低,焦烧时间（ts2）和正硫化时间（t90）延长,硫化速率（Vc）降低;热氧、臭氧、光氧老化前后定伸应力有所降低,热氧老化前的拉伸强度降低,老化后的拉伸强度增加,臭氧和光氧老化后的拉伸强度降低,拉断伸长率上升。     

Research Note: Measurement of Ozone via an Indirect Gas Chromatography Method

Gas chromatography was used to measure the ozone concentration in oxygen produced by an ozone generator. In this indirect method, the ozone reacts with the coating of the capillary column and produces carbon dioxide, which is then detected. The primary methods of calibration for this technique were based on a wet-chemistry process and absorption of ultraviolet light. This finding also is important if the primary reason for using gas chromatography is detection of carbon dioxide, as artificially high readings of carbon dioxide would be measured in the presence of ozone. The method was tested for ozone concentrations of 3–70?mg/L but the method should also be applicable to higher concentrations.     

UV-irradiated ozonation of water-soluble polymers

The effect of ultraviolet light on the ozonation of some water-soluble polymers such as polyethylene glycol, polyacrylamide, carboxymethyl cellulose, and poly(vinyl alcohol) was investigated. Ultraviolet light irradiation accelerated the ozonation. Acceleration was caused by the decomposition of ozone by ultraviolet light, which produced active species.     

臭氧氧化法制备苯二酚的研究

研究了臭氧氧化法生产苯二酚的可行性,并对苯酚的Fe2＋／O3体系反应工艺条件进行了初步探索,得到了最佳反应条件：用硫酸亚铁做催化剂,反应温度35℃,pH值为3,臭氧吹入速度为150L／h,反应20min时,苯二酚收率可达到23．5％。实验发现,pH在酸性条件下能够有效控制臭氧的氧化能力,有利于苯二酚的生成;反应温度对反应产物影响极大,温度低于20℃有利于对苯二酚的产生,温度在25℃到40℃之间有利于邻苯二酚的生成,间苯二酚在45℃以下均可少量生成。     

Vapor phase oxidation of dimethyl sulfide with ozone over V2O5/TiO2 catalyst

The removal of volatile and odorous emissions from pulp and paper industrial processes usually generates secondary pollution which is treated further by scrubbing, adsorption, and catalytic incineration. Studies using a flow reactor packed with 10% vanadia/titania (V₂O₅/TiO₂) catalyst showed complete conversion of dimethyl sulfide (DMS) in the presence of ozone. The molar yields of partial oxidation products were only 10–20%. Small amounts of partial oxidation products, such as and dimethyl sulfone (DMSO₂), dimethyl disulfide (DMDS), and dimethyl sulfoxide (DMSO), were also formed. The results of the oxidation of DMS using ozone only, ozone plus catalyst, and oxygen plus catalyst suggest that the combined use of O₃ with catalyst is essential for the complete destruction of DMS to CO₂ and SO₂. A Box-Behnken design was used to determine the factors that have a significant effect on the conversion and selectivity of the products. It was concluded that product selectivity is strongly influenced by temperature, gas hourly space velocity (GHSV), and ozone concentration. The catalysts were characterized using XRD, surface area measurements, and SEM techniques. Time-on-stream studies carried out in a 500 ppmv gas stream held at 150 °C for 6 h, using 2 g of the catalyst, an ozone-to-DMS molar ratio of 0.9, and a GHSV of 37,000 h⁻¹, yielded 99.9% conversion of DMS. A plausible reaction mechanism has been proposed for the oxidation of DMS based on reaction product distribution and possible intermediates formed.     

紫外光辐射下臭氧在水中的分解动力学

研究了紫外光辐射下臭氧在水中的分解过程。实验表明，稳态液相臭氧浓度随气速的增加而增加，但随pH值和紫外光强度的增加而降低。根据双膜理论建立了臭氧分解过程的动力学模型，并得出了臭氧分解速率常数的迭代计算式。由计算结果知，在恒定温度（30℃）下，速率常数与气相速率和pH值无关，而与紫外光强度的0.617次方成正比。     

The Return of Ozone and the Hydroxyl Radical to Wastewater Disinfection

The City of Phoenix, Arizona is investigating various disinfection technologies for its 91st Avenue wastewater treatment facility: (1) ultraviolet light (UV), (2) ozone, (3) UV/hydrogen peroxide, (4) ozone/hydrogen peroxide, (5) and UV/ozone. In addition to providing disinfection, the City would like to consider the removal of endocrine disrupting chemicals (EDCs) and personal and pharmaceutical care products (PPCPs) in the treatment technology evaluation. To identify the most economical disinfection system, the evaluation included bench-scale testing of the technologies considered and a year-long water quality monitoring study. This paper presents the results of the bench-scale analyses and estimated capital and O&M costs.     

光诱导α-氨基酸的脱羧加成反应

文章主要研究以α-氨基酸和缺电子烯烃作为反应底物的Michael加成反应,以乙腈作溶剂,菲(phen)、1,4-二氰基萘(DCN),1,4-二氰基苯作光敏剂,在紫外光的照射下通过单电子转移过程,与缺电子烯烃发生加成反应,形成一系列脱羧加成产物。该类反应条件温和,产物的产率达65%。     

Effects of atmospheric pollutants at high temperature on the adhesion of RFL-coated tire cords to rubber

The examination of treating oven pollutant effects on the adhesion of RFL-coated polyester and nylon tire cord to rubber was conducted using a hot strip adhesion test. Ozone, ultraviolet light, and ozone–ultraviolet light were examined at 140°F. Nitrogen oxides, sulfur dioxide, and air were tested at 320°F. Ozone and ozone–UV (singlet molecular oxygen) systems were many orders of magnitude greater degradants than the other pollutants known to exist in the ovens. The remaining pollutants tested were ranked in order of degradation effect with NO₂ > NO ? SO₂ ≡ air ≡ heat alone. The mechanism for adhesion loss involves addition to the olefinic double bonds to reduce unsaturation sites for cure.     

UV and ozone treatment of polypropylene and poly(ethylene terephthalate)

The effects of exposure to ultraviolet (UV) light and ozone, separately and in combination, were investigated with respect to polypropylene (PP) and poly(ethylene terephthalate) (PET) surfaces. Three combinations of UV light and ozone were studied: ozone only, UV light in air (producing ozone), and UV light in air (producing ozone) supplemented by additional ozone in the incoming air. The effect of the exposure time of the PP and PET to each treatment was studied. The samples were analyzed by X-ray photoelectron spectroscopy (XPS) to determine the surface composition, and by dynamic contact angle to determine the water wettability. The results showed that the effect of the treament was dependent on the properties of the exposed polymer, with PET being more sensitive to the UV light and PP being more sensitive to the reactive species in the gas. The exposure times studied ranged from 1 to 90 min. By monitoring the oxygen uptake levels, we were able to determine that surface modification occurred within minutes. The possible reactive species and mechanisms are discussed.     

加氢改性二氧化钛的可见光光催化性能研究

针对二氧化钛的禁带宽度大、太阳能利用率低的问题,对合成的纳米二氧化钛部分加氢还原改性,制备了可见光响应二氧化钛光催化材料。水热法合成了锐钛矿相的二氧化钛纳米粒子,用高压低温加氢还原和常压高温加氢还原两种方法进行改性,用X射线粉末衍射仪、扫描电子显微镜表征其结构和形貌,用固体紫外漫反射光谱研究其光响应范围,以罗丹明B的可见光降解反应为探针反应,初步研究其光催化性能,结果表明常压高温加氢处理后的锐钛矿二氧化钛纳米粒子具有更好的可见光光催化性能。     

臭氧氧化法处理硝基苯废水实验研究

采用臭氧氧化法处理硝基苯溶液,考察了反应时间、硝基苯浓度、溶液pH、臭氧流量等因素对硝基苯降解率的影响。研究结果表明：初始浓度200 mg/L时,pH 9.5、臭氧流量为300 mg/h,经30 min后硝基苯去除率达到95.3%以上。硝基苯降解反应符合一级反应动力学。TOC降解速率低于硝基苯分子降解速率,反应30 min后,TOC去除率比硝基苯去除率低45%左右,表明伴随着硝基苯的分解,由？OH或臭氧和硝基苯分子作用生成一系列中间产物。     

Vapor phase oxidation of dimethyl sulfide with ozone over V2O5/TiO2 catalyst

The removal of volatile and odorous emissions from pulp and paper industrial processes usually generates secondary pollution which is treated further by scrubbing, adsorption, and catalytic incineration. Studies using a flow reactor packed with 10% vanadia/titania (V₂O₅/TiO₂) catalyst showed complete conversion of dimethyl sulfide (DMS) in the presence of ozone. The molar yields of partial oxidation products were only 10–20%. Small amounts of partial oxidation products, such as and dimethyl sulfone (DMSO₂), dimethyl disulfide (DMDS), and dimethyl sulfoxide (DMSO), were also formed. The results of the oxidation of DMS using ozone only, ozone plus catalyst, and oxygen plus catalyst suggest that the combined use of O₃ with catalyst is essential for the complete destruction of DMS to CO₂ and SO₂. A Box-Behnken design was used to determine the factors that have a significant effect on the conversion and selectivity of the products. It was concluded that product selectivity is strongly influenced by temperature, gas hourly space velocity (GHSV), and ozone concentration. The catalysts were characterized using XRD, surface area measurements, and SEM techniques. Time-on-stream studies carried out in a 500 ppmv gas stream held at 150 °C for 6 h, using 2 g of the catalyst, an ozone-to-DMS molar ratio of 0.9, and a GHSV of 37,000 h⁻¹, yielded 99.9% conversion of DMS. A plausible reaction mechanism has been proposed for the oxidation of DMS based on reaction product distribution and possible intermediates formed.