臭氧氧化对有机物降解的构效关系

臭氧氧化作为一种高级氧化技术,普遍应用于水处理工艺中。以靛蓝、甲基蓝、铬黑T、橙黄G、皂黄、萘酚绿B为研究对象,根据试验数据分析不同温度下臭氧氧化降解六种有机物的TOC去除率和TOC去除速率常数的变化趋势,分析结果表明温度升高对臭氧氧化降解有机物具有促进作用。根据阿伦尼乌斯公式建立了有机物TOC去除速率常数和温度的关系,估算出臭氧氧化有机物反应活化能,利用量子化学软件Gaussian 09软件计算了六种有机物的15个量子化学参数,进行臭氧氧化有机物的反应活化能与量子化学参数之间的相关性分析,结果表明臭氧氧化六种有机物的反应活化能主要与E_(HOMO)、E_(LUMO)和q(C-)_(min)相关。     

臭氧氧化法处理密闭式清洁站垃圾沥滤液试验研究

以密闭式清洁站产生的垃圾渗滤液为对象,控制反应体系条件为:酸性(pH<4),室温,研究臭氧氧化反应时间、曝气方式、曝气流量与有机物去除率之间的关系。研究结果表明,臭氧氧化试验反应前2 h,反应速率较快,对COD、NH3-N、BOD5的去除率分别达到52.8%、46.8%、55.8%,此后臭氧氧化速率降低,去除率变化不大;当曝气流量提升到2 L/min以后,有机物的去除效率变化不明显;一定的曝气量下,曝气方式对有机物的去除几乎无影响。经过臭氧氧化反应后,渗滤液浓度依旧较高,因此臭氧氧化须与其它处理技术相结合,才能满足出水水质的要求。     

UV/O3-BAC与O3-BAC处理二级出水中有机污染物的研究

将光助臭氧氧化-生物活性炭(UV/O3-BAC)新型组合工艺用于处理城市污水厂二级出水中有机污染物.考察了臭氧剂量、氧化反应时间和生物活性炭停留时间对出水水质影响,TOC去除率随着臭氧剂量、氧化反应时间和生物活性炭停留时间增加而增加;其优化工艺参数为:臭氧剂量为3 mg/L,氧化反应和生物活性炭空塔停留时间均为15 min.在优化工艺参数下,UV/O3-BAC工艺对TOC和UV254平均去除率分别达到46%和71%,比O3-BAC工艺(同样工艺参数下)对TOC和UV254平均去除率分别提高35.3%和14.5%;两组合工艺对有机物去除具有协同效应,其中UV/O3-BAC工艺的协同效应比O3-BAC工艺大.UV/O3和O3过程将水中大分子有机物氧化成小分子,增加了出水的可生化性,从而有利于后续BAC对有机污染物的去除.二级出水中主要有机污染物是酚类和酞酸酯等,经氧化处理后,二级出水中芳香烃和含一C=C-有机物消失或浓度减少,同时也生成一些小分子氧化产物,但经BAC处理后,污染物种类和浓度均大为减少.     

污水二级出水有机物(EfOM)的组成、性质及处理技术

污水二级出水有机物(EfOM)是污水经二级生化处理后剩余的有机物,主要来源于天然有机物、微生物代谢产物和人工合成难降解有机物。EfOM的存在不仅决定了二级生化出水能否达标排放,而且对污水回用性能产生重要影响。介绍了EfOM的主要组成及影响,对EfOM的基本性质(分子量分布、亲疏水性、荧光特性等)进行了分类归纳,并对现有处理技术(混凝、吸附、高级氧化、生物过滤、膜分离)处理EfOM性能进行了总结和评价,对EfOM相关的研究方向进行了初步展望。     

臭氧联合混凝去除长江源水中有机污染物的小试研究

以长江重庆段水质为研究对象,考察臭氧对混凝去除水中有机污染物的影响。结果表明,臭氧预氧化后,TOC、UV254的去除率分别为2.5%、11.0%,说明臭氧可以部分彻底氧化去除水中有机物,预氧化后有机物的结构改变比较明显;相比于单独混凝,臭氧联合混凝使TOC和UV254的去除率分别提高了4.9～5.3和12.1～14.2个百分点,臭氧预氧化可以强化混凝对TOC和UV254的去除;臭氧预氧后各个分子段有机物的分布改变比较明显,相对分子质量大于3×103的有机物明显减少,相对分子质量小于3×103的有机物明显增加。相比于单独混凝,臭氧联合混凝主要提高了相对分子质量大于3×103的有机物去除率,降低了相对分子质量小于3×103有机物的去除率。     

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。     

臭氧氧化处理苯胺废水

采用臭氧氧化法处理苯胺溶液，考察了反应时间、苯胺浓度、溶液pH、臭氧流量等因素对苯胺降解率的影响。研究结果表明：初始浓度200mg／L时，pH值9．0、臭氧流量为300mg／h，经10min后苯胺去除率达到99％以上。苯胺降解反应符合一级反应动力学。TOC降解速率低于苯胺分子降解速率，反应30min后，TOC去除率比苯胺去除率低40％左右，表明伴随着苯胺的分解，生成一系列中间产物。     

二级出水中有机物深度处理工艺的研究进展

随着我国经济发展,城市污水和工业废水排放量不断增加。由于目前污水处理厂多采用生物法,二次出水中仍含有部分难以被生物降解的有机物,如果不经过处理直接排放,会对人体和生态环境造成威胁。污水二级出水有机物(EfOM)是污水经二级生化处理后剩余的有机物,主要来源于天然有机物、可溶性微生物产物和合成有机化合物。文中介绍了EfOM的主要组成并对其进行了量化和表征,综述了各种深度处理工艺(即混凝、高级氧化、吸附、膜分离)在去除EfOM方面的性能和优缺点,并通过组合工艺对污染物去除效果与单一工艺进行对比分析,为EfOM的有效去除提供理论依据。     

非均相催化臭氧化深度处理钻井废水的效能研究

采用单独臭氧氧化、MnO2吸附和O3/MnO2催化氧化3种体系对经过混凝处理后的钻井废水进行深度处理,重点研究了O3/MnO2催化氧化体系去除钻井废水中有机物(以COD计)的效能。结果表明:相比单独臭氧氧化和MnO2吸附体系,O3/MnO2催化氧化体系能显著提高COD和TOC的去除率;COD去除率随着臭氧投加量和催化剂投加量的增加、pH的升高和反应时间的增加而增大;在臭氧投加量为80 mg/L、pH为11.5、催化剂投加量为20 g/L、反应时间为40 min的最佳工艺条件下,COD和TOC的去除率分别达到87.51%、83.18%,COD从686.28 mg/L降至85.72mg/L,出水达到《污水综合排放标准》(GB 8978—1996)的一级标准要求。     

臭氧法降解水中4-氟苯酚动力学研究

采用臭氧法降解4-氟苯酚模拟废水,研究4-氟苯酚降解影响因素和动力学。考察了反应液初始p H、反应物初始浓度、臭氧投量对臭氧氧化4-氟苯酚反应速率的影响。结果表明,4-氟苯酚初始浓度1 mmol/L,p H 10.0,常温常压下反应120 min后,4-氟苯酚总模拟废水的有机碳去除率为56.77%。采用幂指数方程描述反应动力学,4-氟苯酚模拟废水在臭氧氧化下的TOC去除符合表观一级动力学,并得到不同条件下的表观反应速率常数。     

Ozonation of Phenol-Containing Wastewater Using O3/Ca(OH)2 System in a Micro Bubble Gas-Liquid Reactor

The degradation of phenol in aqueous solution was investigated in an integrated process consisting of O₃/Ca(OH)₂ system and a newly developed micro bubble gas-liquid reactor. The effects of operating parameters such as Ca(OH)₂ dosage, reactor pressure, liquid phase temperature, initial phenol concentration and inlet ozone concentration on degradation and mineralization (TOC removal) were studied in order to know the ozonation performance of this new integrated process. It is demonstrated that the degradation and TOC removal efficiency increased with increasing inlet ozone concentration and increasing Ca(OH)₂ dosage before 2 g/L, as well as decreasing initial phenol concentration. The optimum Ca(OH)₂ dosage should exceed Ca(OH)₂ solubility in liquid phase. The reactor pressure and liquid phase temperature have little effects on the removal and TOC removal efficiency. When Ca(OH)₂ dosage exceeded 3 g/L, the degradation and TOC removal of phenol almost reached 100% at 30 and 55 min, respectively. The intensification mechanism of Ca(OH)₂ assisted ozonation was explored through analysis of the precipitated substances. The mechanism for Ca(OH)₂ intensified mineralization of phenol solution is the simultaneous removal of CO₃^2- ions, as hydroxyl radical scavengers, due to the presence of Ca²⁺ ions. Results indicated that the proposed new integrated process is a highly efficient ozonation process for persistent organic wastewater treatment.     

O3 based advanced oxidation for ibuprofen degradation

The degradation of the anti-inflammatory ibuprofen (IBP) was evaluated by several advanced oxidation processes. IBP was treated by single ozonation and oxidation with hydrogen peroxide (H₂O₂), as well as a combination of these treatments. In order to improve the efficiency, the presence of catalysts such as original carbon nanotubes, labelled as CNT, and iron oxide supported on carbon nanotubes, named as Fe/CNT sample, was considered. The evolution of IBP degradation, mineralization and toxicity of the solutions was assessed. The formation of intermediates was also monitored. In the non-catalytic processes, IBP was faster removed by single ozonation, whereas no significant total organic carbon (TOC) removal was achieved. Oxidation with H₂O₂ did not present satisfactory results. When ozone and H₂O₂ were combined, a higher mineralization was attained (70% after 180 min of reaction). On the other hand, in the catalytic processes, this combined process allowed the fastest IBP degradation. In terms of mineralization degree, the presence of Fe/CNT increases the removal rate in the first hour of reaction, achieving a TOC removal of 85%. Four compounds were detected as by-products. All treated solutions presented lower toxicity than the initial solution, suggesting that the released intermediates during applied processes are less toxic.     

Effect of temperature on the ozonation of textile waste effluent

Ozonation in batch experiments were conducted at elevated temperatures to study the influence of temperature on the efficiency of ozonation. The effect of temperature on ozonation was determined by measuring the extent of colour removal and the reduction of chemical oxygen demand (COD) and total organic carbon (TOC) of a textile waste effluent. It was found that increasing the temperature causes a decrease in the levels of colour, COD and TOC. Complete mineralisation of the dye molecule, however, did not occur to an appreciable extent. The efficiency of colour removal was 71.3%, whilst the COD and TOC reduction efficiency was 20.3 and 19.3%, respectively, at the highest temperature studied (50 °C). The removal efficiency of COD, however, did not improve significantly when the temperature was increased from 40 to 50 °C.     

Catalytic Ozonation of Sulfosalicylic Acid

The investigation of heterogeneous catalytic ozonation of sulfosalicylic acid (SSal) in aqueous solution is reported in this paper. It was found that catalytic ozonation in the presence of V-O supported on silica gel had a more positive effect on the removal rate (62% in 30 min) of total organic carbon (TOC) than that of ozonation alone (20% in 30 min), and the catalyst supported on TiO₂ had similar results. The experimental results also showed that the ozone dosage should be sufficient for achieving the catalytic effect. Efficient removal of TOC in catalytic ozonation was probably attributed to producing more powerful oxidants than molecular ozone.     

Degradation of Acid Black 210 by advanced oxidative processes: O3 and O3/UV

Acid Black 210 (AB-210) dye is one of the most black dyes used by the leather industry. In the present work, AB-210 degradation in aqueous solution by ozonation (O₃) and ozonation with ultraviolet (UV) radiation (O₃/UV) was investigated. The effects of pH, initial dye concentration and UV radiation were studied in laboratory scale. Removal was evaluated in terms of residual AB-210 concentration in the treated solution and mineralization efficiency was evaluated by total organic carbon (TOC) analysis. The results indicated that AB-210 is quickly degraded after 15 min but not totally mineralized. It was observed that dye removal of 100% was achieved at pH 3, 7, and 11, while mineralization was found to increase with the pH (55% at pH 11). Concerning UV-C radiation, it enhanced AB-210 degradation at pH 3 but did not reveal any significant effect at pH 7 and 11.     

催化臭氧分离膜制备及去除腐殖酸机理分析

以微污染水为处理对象,考察了新型催化膜的过滤性能及抗污染行为。实验过程中采用溶胶凝胶法制备纳米TiO2粉体,将不同焙烧温度的纳米TiO2颗粒加入铸膜液中,利用相转换法制备催化膜。采用X射线衍射（XRD）及扫描电子显微镜（SEM）对膜进行表征,对膜的纯水通量、孔隙率、接触角、膜的催化性能及分离特性进行了系统地测定。实验结果表明,金红石型TiO2催化膜对腐殖酸（humic acid,HA）及总有机碳（total organic carbon,TOC）的去除效率分别为70%及65%以上,说明金红石型TiO2催化膜具有较高的污染物去除及抗污染特性。实验结果证实新型多功能膜对于水处理的实际应用具有较大的发展潜力。     

Degradation of Two Persistent Surfactants by UV-Enhanced Ozonation

In this study the treatment efficiency of different ultraviolet (UV)-enhanced ozonation processes for degradation of two surfactants, sodium dodecylbenzene sulfonate [200 mg/L or 0.3 critical micelle concentration (CMC)] and a nonylphenol ethoxylate with 40 oxyethylene units (200 mg/L ~0.5 CMC), were investigated in laboratory-scale experiments at ambient temperature. The absorbance band of the aromatic ring of the surfactants was monitored during the oxidation process. The reduction in chemical oxygen demand (COD) and total organic carbon (TOC) of the surfactant solution was evaluated. The results showed that a combination of UV irradiation and ozonation was considerably more efficient than the individual processes (at least two times more efficient in terms of COD and TOC reductions). The synergistic effect of ozonation and UV irradiation was particularly pronounced when medium-pressure UV irradiation was used. By adding alkali to the solution, the efficiency of the UV-enhanced ozonation increased with respect to COD reduction but decreased with respect to TOC reduction. This indicates partial oxidation with lower degree of mineralization of the surfactants.     

Enhancement in mineralization of some natural refractory organic compounds by ozonation–aerobic biodegradation

Two schemes, the first involving ozonation followed by final aerobic biodegradation (phase I experiments), and the second involving initial aerobic biodegradation, followed by ozonation and subsequent final aerobic biodegradation (phase II experiments), were examined for enhanced mineralization of refractory model compounds, viz. gallic acid, tannin and lignin. In all cases, and irrespective of the applied scheme, chemical oxygen demand (COD), total organic carbon (TOC), COD/TOC ratio, and specific UV absorbance at 280 nm attributed to the model compounds decreased with application of increasing ozone dose. The residual organic matter remaining after ozonation exhibited enhanced aerobic biodegradability in all cases. Further, in all cases and irrespective of the applied scheme, the overall amount of COD and TOC removed through the combination of ozonation and biodegradation processes increased with increase in ozone dose for all three model compounds, and more than 90% COD removal could be achieved with an ozone dose of 3 mg ozone absorbed per mg initial TOC, as compared with approximately 40% COD removal when no ozone was applied. Treatment by the first scheme resulted in the fraction of starting COD removed through biodegradation decreasing with increase in ozone dose in all cases, while this fraction increased or remained constant during treatment using the second scheme. In the case of tannin and lignin, similar overall COD removal could be achieved at lower ozone doses using scheme II. Due to incorporation of the initial aerobic biodegradation step in scheme II, the ozone requirement for additional mineralization, ie mineralization over and above that achieved by aerobic biodegradation, was also lower than that in scheme I. Copyright © 2005 Society of Chemical Industry     

Mineralization of bisphenol A by advanced oxidation processes

BACKGROUND: Endocrine disruptors, as in the case of bisphenol A (BPA), are increasingly found in aqueous effluents. The degree of mineralization of a bisphenol A (BPA) aqueous solution after applying several oxidation treatments has been investigated. RESULTS: UV‐C photolysis of BPA allowed calculation of the quantum yield, ϕ_λ=254 = 0.045 ± 0.005 mol Einstein⁻¹ but only 15% of the initial organic carbon content (TOC) was eliminated. Better results (80% conversion) were obtained after TiO₂ addition. Ozone inmediately reacts with BPA. Again, TiO₂ addition in the presence of O₃ was capable of increasing the mineralization level (60%). The photolytic ozonation of BPA was capable of completely eliminating TOC. The presence of activated carbon in the O₃/UV and O₃/UV/TiO₂ systems significantly enhanced the TOC removal reaction rate (100% conversion in 20 min). CONCLUSIONS: Processes such as ozonation or photolysis are capable of efficiently removing BPA from water however, mineralization levels are rather low. Addition of TiO₂ to O₃ or UV‐C significantly enhances TOC removal. The remaining organics still account for an average 20–40% of the initial organic carbon. The combination of O₃/UV‐C is capable of completely mineralizing BPA. Activated carbon and/or TiO₂ addition to the system O₃/UV‐C improves the TOC depletion rate. Copyright © 2008 Society of Chemical Industry     

Improvement of Biodegradability of Oil Field Drilling Wastewater Using Ozone

The possibility of improving the biodegradability of drilling wastewater using ozone was investigated following coagulation pretreatment. The biodegradability of wastewater was improved significantly following the start of ozonation, and the molecular weight of organic compounds decreased continuously with the progress of oxidation. It is interesting that minimum biochemical oxygen demand, total organic carbon (BOD/TOC) ratio (0.4 g/g) was observed when wastewater was treated with ozone continuously for 15 min. The combination of ozonation for 5 min (ozone consumption ratio of 2.6 g ozone/g TOC) followed by biological degradation produced a total TOC removal rate of 54.3%, which was comparable to direct ozonation for 30 min under the same conditions (TOC removal rate of 54.9%; ozone consumption ratio of 8.7 g ozone/g TOC). It is clear that biological treatment following short-term ozonation was very efficient in TOC removal. A process of successive coagulation-precipitation, ozone oxidation, and biodegradation seemed to be a good option for drilling wastewater treatment.