水/载O3有机溶剂两相臭氧氧化法降解水体中氯霉素

以水/载O₃有机溶剂（全氟萘烷）为新型两相臭氧氧化体系,研究了臭氧在全氟萘烷中的溶解度和稳定性,并考察了pH、NaHCO₃和叔丁醇对两相体系中臭氧稳定性的影响;以水体中氯霉素为研究对象,考察了初始pH值和自由基抑制剂对两相臭氧氧化体系降解氯霉素效果的影响。结果表明：初始水相pH增大有利于氯霉素的降解;自由基抑制剂对两相体系氧化降解氯霉素影响不显著。     

O3/TiO2/γ-Al2O/UV降解草酸

采用臭氧与TiO2/γ-Al2O/UVV联用技术对降解草酸进行研究。考察了进气流量、草酸初始浓度、催化剂投加量、pH值及温度等因素对草酸降解的影响。研究表明,在一定范围内,随着进气流量的增加、温度的升高都会促使草酸的降解速率加快;溶液pH值对催化臭氧化有比较重要的影响,pH值2时,草酸的去除率最高。     

Investigation and Modeling of Ozone Penetration in a Fixed Bed Reactor for Purification of Soil Contaminated with Anthracin

In this research, the influence of effective parameters on ozone penetration in the soil contaminated with anthracin has been investigated. The soil was then contaminated with anthracin, a polycyclic aromatic hydrocarbon, after washing and moisture removal stored in a dark environment for one week in closed containers. The parameters studied are as follows: the soil height, the soil particle size, contaminant concentration, ozonation time, and moisture percent. The maximum removal efficiency was 92%. In this study, it was observed that by changing the size of the soil particles, there are significant changes in the penetration rate. Also, the pollutant concentration, the height of the soil column, and moisture affect penetration rate. It was also observed that the highest penetration rate occurred in the first 10 min of the ozonation process. In the next step, by obtaining the governing equations for the decomposition of ozone by contaminate, organic and inorganic materials, soil active sites and spontaneous ozone decomposition, a model for ozone penetration in the soil was presented, and by comparing experimental data and modeling results, the coefficients of reaction rate of ozone kinetic reactions with pollutant, organic matter and inorganic soil, soil active sites and spontaneous ozone decomposition were obtained approximately.     

Application of Response Surface Methodology for Coffee Effluent Treatment by Ozone and Combined Ozone/UV

This paper reports a study using ozone (O₃) and combined ozone/ultraviolet (O₃/UV) processes for color removal and caffeine degradation from synthetic coffee wastewater using a second-order response surface methodology (RSM) with a three-level central composite face-centered (CCF) design. The effects of O₃ concentration, initial pH, and reaction time were examined for both processes. The reaction time and pH were statistically significant for caffeine degradation and color removal. In the ozonation process, higher caffeine degradation and color removal were observed in alkaline pH, indicating that ozone attacks indirectly, consequently generating hydroxyl radicals. Regarding the ozone/UV process, it was observed that lower caffeine degradation and color removal occurred at neutral pH, indicating an adverse effect due to lower ozone dissolution and consequently the production of a smaller amount of free hydroxyl radicals. The achieved results showed that the techniques were efficient for color removal (85% and 99%, respectively) and caffeine degradation (88% and 98%, respectively).     

Ozonation of organic compounds in alkaline aqueous media

Effect of pH on the aqueous phase ozonation of various organic compounds was investigated. The reaction was accelerated in alkaline media due to the formation of active hydroxyl radical by an interaction of ozone with hydroxide ion. However, in a strongly alkaline media (pH < 11.9), hydroxyl radical dissociated into less reactive oxygen ion and the efficiency of ozonation decreased. By means of the theory of gas absorption accompanied by chemical reaction, it was found that the rate of the decomposition of ozone in the presence of about 300 ppm of 1-butanol was 5-80 times larger than that catalyzed only by hydroxide ion in the pH range of 11-13. Efficiency of ozonation showed that an optimum range of pH for the removal of total organic carbon was 9-10.     

A New Approach to Determine the Practical Ozone Dose for Color Removal from Textile Wastewater

In this study, the effect of applied ozone dose and pH on color removal from textile wastewater was studied. A lab-scale ozonation system was used in the experiments. When the applied ozone dose increased, the color removal efficiency and the rate constants increased, whereas ozone utilization ratio decreased. On the other hand, increasing the pH increased color removal efficiency and ozone consumption but decreased specific ozone dose. By using the experimental results, a new model has been developed to determine the required ozone dose for the removal of color. By means of this method, it was possible to determine the required ozone dose for reducing the amount of color up to desired levels. Experimental results and the model predictions were in good agreement not only for textile wastewater but also for different industrial effluents. Some parameters affecting ozone utilization such as pH, could also be incorporated into the model.     

臭氧氧化双酚A的性能及机理

采用臭氧氧化法在动态条件下降解双酚A,考察了臭氧浓度、水样进水流速、pH、双酚A初始浓度及温度对氧化降解双酚A效果的影响,探究了臭氧氧化双酚A的反应机理。结果表明,臭氧对溶于水中的双酚A具有良好的去除效果,在反应条件(臭氧浓度11.04 mg/L、水样进水流速2 mL/min、原水pH=6.83、双酚A初始浓度10 mg/L、温度40℃)下,去除率达86.12%。增加臭氧浓度或适当升高温度可增加臭氧氧化双酚A去除率。pH和进水流速的提高会降低双酚A去除率。偏酸性条件下,臭氧降解双酚A的效果更好。臭氧氧化双酚A反应活化能较低,属于快速反应。臭氧浓度不变,增加双酚A初始浓度会使其去除率减小。臭氧氧化双酚A以臭氧直接氧化为主,同时也存在羟基自由基间接氧化。     

新型铁铈复合氧化物催化臭氧氧化工艺去除对硝基苯酚

对硝基苯酚(4-NP)作为一种难降解的有机污染物,在自然环境中半衰期较长,对水生生物及水体环境均有不利影响.采用水热法制备新型铁铈复合氧化物,将其作为臭氧催化剂用于去除水中的4-NP.采用单因素试验,探究铁铈摩尔比、臭氧浓度、催化剂投加量、初始pH等因素对4-NP去除效果的影响.结果表明:在铁铈摩尔比为10:1、水中臭...     

Effect of Catalytic Ozonation Coupling with Activated Carbon Adsorption on Organic Compounds Removal Treating RO Concentrate from Coal Gasification Wastewater

This paper reports a novel system of catalytic ozonation coupling with activated carbon adsorption for removing the organic compounds treating in the RO concentrate from coal gasification wastewater. The effect of ozone dosage, catalyst dosage, reaction time, influence pH, and temperature on organic compounds removal were examined for the processes. In the catalytic ozonation process, increasing solution pH, dosages ozone, and catalyst were statistically significant for improving the performance. In addition, the high salinity with chloride concentration of 15 g/L could reduce the catalyst specific surface area by 18%. Thus, high salinity showed negative influence on the catalytic effect in TOC removal. Regarding activated carbon adsorption process, modified activated carbon by NaOH revealed advantages in adsorbing organic compounds treating catalytic ozonation effluent. With the ozone dosage of 120 mg/L, catalyst dosage of 2.0 g/L, catalytic ozonation reaction time of 1 h, and modified activated carbon adsorption time of 1 h, the average TOC removal efficiencies were maintained at the stable level of 58% with the TOC concentration of 26 mg/L.     

Combination of Ozonation and the Fenton Processes for Landfill Leachate Treatment: Evaluation of Treatment Efficiency

Single processes such as ozonation, ozone/hydrogen peroxide, Fenton and several combined treatment schemes were applied for leachate collected from a waste disposal site. The implementation of combined Fenton and ozonation processes resulted in the highest chemical oxygen demand removal (77% from initial value) among all the treatment methods applied, while biodegradability improvement was observed during the Fenton pre-treatment only. Some decrease of chemical oxygen demand was obtained during the single ozonation or combined schemes including ozone resulting in slight if any biodegradability improvement. The addition of hydrogen peroxide to ozonation did not enhance chemical oxygen demand, dissolved organic carbon or biochemical oxygen demand removal compared to ozone alone. Ferric chloride coagulation used as a pre-treatment stage did not improve subsequent chemical oxygen demand removal by ozonation or the Fenton processes. Taking into account the effective chemical oxygen demand, dissolved organic carbon removal and biodegradability improvement the single Fenton process seems to be a preferable treatment method for the leachate treatment. Some reduction in toxicity to Daphnia magna was observed after the application of the studied treatment methods.     

臭氧强化电絮凝处理直接耐晒大红4BS模拟染料废水

采用臭氧强化电絮凝法处理直接耐晒大红4BS模拟染料废水,研究了染料脱色的影响因素及其COD_Cr去除动力学。考察了电流密度、溶液初始pH 值、染料初始浓度、支持电解质浓度、反应温度和臭氧流量对臭氧强化电絮凝法处理4BS染料脱色效率的影响。结果表明,电流密度15 mA·cm^-2,pH值10.0,4BS染料初始浓度100 mg·L^-1,支持电解质浓度3000 mg·L^-1,臭氧流量06 L·h^-1,20 ℃下反应50 min后4BS脱色率达94％以上。COD_Cr去除符合拟二级动力学。     

Remediation of Kraft Effluent by Ozonation: Effect of Applied Ozone Concentration and Initial pH

In this study, the impact of ozone concentration (14 and 7mg/L^?1 applied for 120min) and pH (10 and 12) on color removal, and reduction of dissolved organic matter (DOC) and total phenol of Kraft E₁ effluent was investigated. The degradation kinetics for the all parameters at pH 12 were slower than of those at pH 10. The degradation at pH 10 ceased after approximately 120min, while for the ozonation at pH 12, ozone was still being consumed even after 5h of treatment. When the ozone dose was increased, the removal efficiency increased; however, the DOC removal efficiency continued limited.     

Studies on cerium oxidation in catalytic ozonation process: A novel approach for organic mineralization

A novel regenerative catalytic system has been developed using cerium and ozone in nitric acid medium. It was found that cerium(III) was oxidized to cerium(IV) by ozone in nitric acid medium with good conversion yields. The conversion rate of Ce(III) was measured under various parameters viz. ozone–air flow rate, initial concentration of Ce(III), and concentration of nitric acid at 25 °C. It was found that the conversion of Ce(III) increased with increasing ozone flow rate and concentration of nitric acid while decreased with increasing Ce(III) concentration. The pseudo first order kinetic constants were evaluated for Ce(III) oxidation. The efficiency of this hybrid system comprising of ozone and cerium redox pair towards organic mineralization was evaluated taking phenol as the model organic pollutant and compared with Ce(III) catalyzed and uncatalyzed ozonation processes. The presence of Ce(III) catalyst increased the destruction efficiency of phenol compared to uncatalyzed ozonation whereas a synergetic effect was observed between the cerium redox pair (Ce(III) and Ce(IV)) and ozone towards phenol mineralization and a maximum TOC removal was obtained in the latter case. Kinetic interpretations have been made with some simplifying assumptions owing to the much complex nature of ozone and metal ion interactions. This hybrid catalytic ozonation process may find its suitability for continuous organic destruction at room temperature.     

超声波臭氧技术联用处理对硝基苯胺废水研究

分别采用臭氧、单频超声协同臭氧处理、双频超声强化臭氧氧化处理对硝基苯胺废水,考察了废水初始pH、臭氧通入量、超声波频率及功率等因素对处理效果的影响。结果表明,超声与臭氧协同作用可以有效地降解对硝基苯胺废水,且以双频超声强化臭氧氧化效果最佳,其优化处理条件:pH为11,臭氧的产生速率为30 mg.min-1,双频功率搭配为110 W-50 W,反应时间为50 min。此时COD、对硝基苯胺和硝基苯的去除率分别为96.4%、99.8%和98.8%,经处理后的水质能达到GB 8978-1996的一级排放标准。     

可见光下Cu2O/TiO2催化臭氧氧化头孢曲松钠性能研究

抗生素是治疗各种传染病的常用药物,但残留在水环境中的抗生素会对生态系统造成威胁。因此,探索去除水环境中抗生素的有效方法具有重要意义。由于光催化臭氧氧化技术可以高效降解和矿化水体中的污染物,该技术受到广泛关注。本工作通过浸渍-化学还原法制备Cu₂O/TiO₂复合材料并将其作为可见光催化臭氧氧化头孢曲松钠(CRO)的催化剂。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积分析仪(BET)和紫外-可见漫反射光谱仪(UV-Vis DRS)对Cu₂O/TiO₂形貌结构和光学性能进行表征,考察了Cu₂O/TiO₂配比、Cu₂O/TiO₂投加量、臭氧浓度、头孢曲松钠初始浓度、溶液初始pH值等因素对可见光催化臭氧氧化头孢曲松钠的影响。结果表明,Cu₂O对TiO₂的掺杂改性使材料孔容和平均孔径增大,能带宽度减小,...     

活性炭负载Fe~(3+)催化臭氧氧化水中双酚A

采用浸渍法在活性炭上负载铁制备催化剂Fe/AC,用于催化臭氧氧化水中内分泌干扰物双酚A(BPA),研究了Fe/AC/O3体系的协同效应,探讨了Fe/AC投加浓度、臭氧浓度和BPA初始浓度等工艺参数的作用规律,并分析了Fe/AC/O3体系在不同pH值下的催化反应机制。结果表明,在Fe/AC/O3体系下,反应60 min后,BPA和COD的去除率分别为97.44%和69.47%,效果明显优于臭氧体系的70.15%、30.89%和活性炭体系的14.69%、7.53%之和,具有明显的协同作用;Fe/AC/O3体系降解BPA符合一级反应动力学,当Fe/AC的投加浓度为5.0 g/L,臭氧浓度为15.0 mg/L,BPA初始浓度为50.0 mg/L时,Fe/AC/O3体系降解BPA的反应速率常数为0.05972 min-1;其反应机制受溶液pH值的影响,在酸性条件下是吸附和臭氧直接氧化共同作用,而在碱性条件下以·OH间接氧化为主,活性炭上负载的Fe3+促进了·OH的生成,大大提高了BPA的反应效率和矿化率。     

Ozonation of Textile Effluents and Dye Solutions in the Presence of Activated Carbon under Continuous Operation

Abstract

Ozonation was found to be effective for the decolorization of solutions, but has only a slight effect on TOC removal. On the other hand, adsorption on activated carbon improves the TOC removal, but the progressive uptake of the organic contaminants during the adsorption process decreases its removal efficiency. Decolorization, mineralization, and ozone consumption of colored solutions were evaluated under continuous operation in a column by three different processes: ozonation, adsorption on a fixed activated carbon bed, and ozonation in the presence of the activated carbon bed. The introduction of an ozone flow in a fixed activated carbon bed enhances both the decolorization of the solutions and mainly the mineralization of the organic matter, even when the activated carbon was previously partially saturated. Activated carbon acts both as an adsorbent and as a catalyst in the ozonation of colored solutions. The column configuration plays an important role in the performance of this system. The configurations in series and with activated carbon in the upper part of the column showed the highest colour and TOC removal for dye solutions.

The results obtained clearly show that the combination of ozone and activated carbon is a promising technique for the final treatment of colored effluents. Practical applicability of this process was validated by treating two industrial textile effluents, collected after two different biological treatments.     

Removal of 1,4-Dioxane and Volatile Organic Compounds from Groundwater Using Ozone-Based Advanced Oxidation Process

Ozone and ozone/peroxide processes were evaluated for the removal of 1,4-dioxane from laboratory water and site groundwater. The effect of process parameters such as solution pH and dosage of peroxide was studied. Ozone alone was not very effective in removing 1,4-dioxane from water (≤ 20% removal). Enhanced oxidation of 1,4-dioxane was achieved by increasing the solution pH or by adding peroxide at neutral pH. Pseudo–first-order rate constants were calculated for the removal of 1,4-dioxane using ozone. Correlations were developed for the consumption of ozone per 1,4-dioxane removed. Acidic and neutral pH conditions resulted in higher consumption of ozone per dioxane removed. Basic solution pH and presence of hydrogen peroxide enhanced the dioxane removal, which resulted in lower consumption of ozone per dioxane removed. Following the lab study, ozonation was used for the remediation of site groundwater contaminated with 1,4-dioxane and chlorinated volatile organics. Presence of 5 mg/L of hydrogen peroxide during ozonation resulted in simultaneous removal of 1,4-dioxane and volatile organics from groundwater to target levels. For the AOP process, removal kinetics was approximately 50% slower in groundwater compared to the lab DI water.     

Degradation of Refractory Organic Pollutants by Catalytic Ozonation—Activated Carbon and Mn-Loaded Activated Carbon as Catalysts

A novel catalyst for the ozonation process was prepared by loading manganese on the granular activated carbon (GAC). Nitrobenzene was used as a model refractory organic micropollutant in this study. The catalytic activity of GAC and the Mn-loaded GAC were studied respectively. The removal efficiency of nitrobenzene by Mn-loaded GAC catalyzed ozonation could reach 34.2–49.9%, with the oxidation efficiency being about 1.5–2.0 times higher than that achieved in GAC catalyzed ozonation and 2.0–3.0 times higher than that achieved by ozonation alone. The effect of pH and the t -butanol on the GAC/ozone process was discussed. The optimum condition for preparing the catalyst was studied.     

Catalysts to improve the abatement of sulfamethoxazole and the resulting organic carbon in water during ozonation

Sulfamethoxazole (SMX), one pharmaceutical compound, has been treated in aqueous solutions with catalysts (copper and cobalt type perovskites and cobalt–alumina) and promoters (activated carbons). Hydrogen peroxide and saturated carboxylic acids were identified as intermediates. The effects of adsorption and pH have been investigated. Removal of the starting SMX accomplished with ozone alone is a fast process but catalytic or promoted ozonation is needed to significantly reduce the resulting organic carbon. SMX is, thus, mainly removed through direct ozone reaction while hydroxyl radical oxidation is the mechanism of removal the remaining TOC. The kinetics of the process has also been investigated. Perovskite catalytic ozonation resulted to be a chemical control process and apparent rate constants for homogeneous and heterogeneous ozonation were determined. For activated carbon ozonation, external diffusion of ozone to solid particles controlled the process rate.