活性炭催化剂臭氧催化氧化处理废水的研究进展

介绍了近年来国内外活性炭催化剂臭氧催化氧化的研究结果,对活性炭及金属负载型活性炭催化剂的反应机理进行了总结。讨论了非均相臭氧催化氧化过程中活性炭的主要作用,活性炭催化剂的表面物化性质、pH值、温度在臭氧催化氧化过程中的影响规律。并提出活性炭催化剂的降解机理以及催化剂性质与有机污染物的化学结构之间的关系还需要进一步的研究。     

臭氧催化氧化处理炼油废水反渗透浓水的研究

双膜工艺广泛应用于污水的深度处理与回用中,但其排放的浓水盐含量高、可生化性差,处理难度极大.采用自制的催化剂及其臭氧催化氧化反应器处理炼油废水反渗透浓水取得了良好效果.探讨了臭氧催化氧化工艺条件对浓水处理效果的影响.结果表明,在最佳处理工艺条件下,处理后的出水达到<污水综合排放标准>(GB8978-1996)中的一级标...     

臭氧催化氧化处理炼油生化尾水的研究

针对生化后炼油废水CODCr无法达标的问题,使用负载Mn-Fe氧化物活性相的陶粒催化剂。采用臭氧催化氧化工艺处理炼油生化尾水。研究中考察了pH、温度、催化剂投加量和臭氧用量等工艺条件对生化尾水中CODCr处理效果的影响。结果表明,当废水初始pH=7,臭氧用量为6.3 mg/min,催化剂投加量为8 g/L时,催化氧化效果最优。室温(22℃)下反应30 min后,出水CODCr浓度为48 mg/L,满足了炼油企业排放标准。所制备的催化剂使用后活性稳定,多次使用后活性无明显降低。     

活性炭负载催化剂臭氧催化氧化处理印染废水研究

以堇青石蜂窝陶瓷、硅藻土、活性氧化铝和活性炭作为载体、金属氧化物(FexOy、CuO、NiO、MnxOy、BaO)作为催化活性组分,对臭氧催化氧化印染废水进行了试验对比,并对影响载铁型活性炭催化剂臭氧催化氧化印染废水的因素进行了研究。结果表明,载铁型的催化剂活性相对较高,当焙烧温度为750℃时,催化性能最好。利用载铁型活性炭催化剂,在臭氧质量浓度为10mg/L、pH值为6、反应时间为60min的条件下,催化氧化具有最佳的效果,COD去除率达86%;催化剂的重复利用性好,连续使用12次,COD的去除率仍可达64%。     

炼油污水的深度处理技术研究

提出了一个经济合理的炼油污水深度处理工艺,即“浮选-生物过滤-臭氧催化氧化-高效过滤”。对抚顺石化分公司污水场生化二沉池出水进行了中试处理试验,研究结果表明,出水的主要几项污染指标COD、油、浊度有明显的降低,可达到用于工业用水的要求。试验效果比较理想,该处理工艺具有很好的经济和社会效益。     

活性炭纤维处理炼油废水展望

介绍了活性炭纤维（ＡＣＦ）在炼油废水中的应用效果,使用寿命,脱附尾气的处理以及经济效益预测。ＡＣＦ对ＣＯＤｃｒ浊度,硫化物,挥发酚,石油类等具有良好的吸附性能,工艺简单,成本低,用作炼油化工废水的二级或三级处理具有广阔的前景。     

臭氧-活性炭工艺深度处理煤制气废水试验研究

以煤制气废水为研究对象,考察臭氧接触时间和臭氧通量对色度和UV254去除效果的影响,研究了臭氧-活性炭工艺在煤制气废水深度处理中的应用效果及影响因素。结果表明,与臭氧直接氧化相比,臭氧催化氧化对色度和UV254的去除效果显著提高,最佳臭氧接触时间为2 h,最佳臭氧通量为5 L/min,在此试验条件下连续运行该工艺深度处理煤化工废水,进水SS浓度和pH值对处理效果有较大影响,CODCr和色度去除率分别为89.95%和86.50%,出水CODCr的质量浓度小于30 mg/L,色度为30度,远优于GB 8978—1996《污水综合排放标准》中一级标准的要求,达到废水回用相关标准的要求。     

臭氧催化氧化-活性炭处理微污染源水

通过连续流试验比较了载锰颗粒活性炭催化臭氧氧化（催化氧化）与臭氧氧化及其后续活性炭过滤对微污染松花江水的处理效能。处理效率最高时,催化氧化对CODMn、UV254、DOC及三卤甲烷生成潜能的平均去除率分别为59.7%、75.8%、40.8%和42.4%,分别是臭氧氧化的3.6、1.4、5.0和2.8倍。随着时间的增加,催化氧化对有机物平均去除率下降,降低程度依次为：UV254〉CODMn〉DOC。催化氧化-活性炭工艺对水力负荷变化有较强的适应能力。臭氧氧化后水中氨氮浓度上升,而催化氧化后稍有下降,同时催化氧化后续活性炭对氨氮的平均去除率在80%左右,比臭氧氧化后续活性炭去除率高而且更加稳定。     

臭氧—BAC工艺用于炼油污水深度处理的中试研究

针对某炼油污水深度处理进行了中试研究,分析了臭氧、生物活性炭(BAC)的作用。研究结果表明,二级生化后污水中仍含有较高浓度的难降解有机物,是后续除盐装置运行不利的主要原因,该类物质难以被陶粒滤料曝气生物滤池有效去除,但可被BAC滤池有效降解。对于有机物的去除,生物活性炭的作用占主导地位,是否投加臭氧影响较小。臭氧对以生物絮体为主的悬浮物质有明显的氧化分解作用,实际应用时应采取必要的预处理措施,减少臭氧的额外消耗。     

活性炭纤维-臭氧氧化处理对硝基苯酚废水的研究

文章采用活性炭纤维吸附处理对硝基苯酚生产废水,回收其中的对硝基苯酚,并通过臭氧氧化进一步去除有机杂质,回收废水中的氯化钠以循环利用。     

Ozone and Activated Carbon for Tertiary Wastewater Treatment

Preozonation of biologically or physically–chemically treated wastewater effluents, followed by passage through granular activated carbon (GAC) for tertiary wastewater treatment was studied at the Duck Creek Wastewater Treatment in Garland, Texas. Whereas the average period of operation for the GAC before exhaustion without ozone pretreatment was 70 days, pretreatment with ozone or with oxygen alone extended GAC operation to at least 480 days, withoutexhaus–tion. Effluent streams consistently metapplicable discharge standards during this period of time, without the necessity of regenerating the GAC.     

Pyruvic Acid Removal from Water by the Simultaneous Action of Ozone and Activated Carbon

Activated carbon (AC) has been used to catalyze the ozonation of pyruvic acid in water. Pyruvic acid conversions were found to be 9 and 37% after 90 min of single ozonation and single adsorption with 40 gL^?1 AC, respectively, while 82% was reached at the same conditions during the AC catalytic ozonation. Also, for similar conditions, mineralization reached values of 67% in the AC catalytic ozonation against hardly 5% in the non-catalytic experiment. The process likely develops through both adsorption of ozone and pyruvic acid on the AC surface and generation of hydroxyl radicals that eventually is the responsible oxidizing species. Rate constants for both non-catalytic ozonation and AC-Ozone catalytic surface reaction, at 20°C and pH 7.5, were found to be 0.025 min^?1 and 87.9 Lg^?1s^?1, respectively. For AC concentrations higher than 2.5 gL^?1 gas-liquid mass transfer of ozone constituted the limiting step. At lower concentrations, internal diffusion plus surface reaction controlled the process rate.     

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.     

Ozone Decomposition over Cobalt Supported on Olive Stones Activated Carbon: Effect of Preparation Method on Catalyst Activity

Aqueous ozone decomposition was studied over highly dispersed cobalt nanoparticles supported on olive stones activated carbon (AC) prepared by: wetness impregnation (Co/AC_w) and incipient wetness impregnation (Co/AC_iw) with respect to pore volume. Nitrogen adsorption-desorption at 77K, SEM, XRD and XPS analyses were used to characterize the catalysts. Analyses results show that Co/AC_w was more uniformly dispersed on the AC than Co/AC_iw. The effect of the presence of tert-butanol as radical scavenger was also studied. Higher catalytic activity was measured for Co/AC_w than Co/AC_iw. Ozone decomposition extent goes to 99% in only 3 min in the presence of Co/AC_w compared to 60% and 58% using Co/AC_iw catalyst and AC, respectively.     

Study of Pre-Treatment of Oil Refinery Wastewater by EEF-Enhanced Micro-Electrolysis

Oil refinery wastewater is rich in organic pollutants and cannot be treated easily. This study involves the pre-treatment of oil refinery wastewater by external electric field (EEF)-enhanced micro-electrolysis technology. The anode was titanium net plated with ruthenium, the cathode was barbed wire, and the Fe/C/Al micro-electrolysis filler as particle electrode. The optimum conditions for EEF-enhanced micro-electrolysis were determined to be as initial pH of 3.0, 10 V EEF voltage, and 0.06 mol/L electrolyte concentrations by studying the influence of different experimental parameters. It was also found that EEF-enhanced micro-electrolysis had a higher efficiency than the traditional micro-electrolysis in the degradation of the organic pollutants present in the oil refinery wastewater. Continuous running results showed the removal rate of COD (chemical oxygen demand), ammonia nitrogen and oil of the effluent was stable, and the average value of the effluent B/C (biochemical oxygen demand/chemical oxygen demand) ratio was 0.454 ± 0.013. The values of EC (energy consumption) and ICE (instantaneous current efficiency) were 9.8 kWh/Kg COD and 340.5%, respectively, when the reaction time was 60 min in oil refinery wastewater pre-treatment by EEF-enhanced micro-electrolysis technology. GC/MS was used to analyze the organic compounds present in the wastewater before and after treatment. UV-visible absorption spectroscopy was used to analyze the degradation process of the organic compounds present in the oil refinery wastewater. The results of these analyses confirmed the technical feasibility of EEF-enhanced micro-electrolysis in the pre-treatment of the oil refining wastewater. Finally, the main mechanism involved in the treatment of refinery wastewater by EEF-enhanced micro-electrolysis technology has been discussed.     

Decomposition of Dissolved Ozone in the Presence of Activated Carbon: An Experimental Study

In aqueous solutions molecular ozone (O₃) decomposes rapidly into secondary radical or ionic species such as (OH^o,, , …). This decomposition is enhanced by many factors, essentially the pH, the temperature, and the organic or inorganic compounds in the solution. The aim of this work is to study the effect of the addition of granular activated carbon on the rate of ozone decomposition in aqueous solutions containing promoter (P) and inhibitor (Q) mixtures. The activated carbon used is laboratory produced from olive stones. We found that the rate of decomposition of ozone in these conditions is described by a pseudo-first-order kinetic: . Experimental results show that adding 15 mg/L of the olive stones activated carbon (OSAC) enhances the rate constant of the P and Q controlled chain depletion by about a factor of two. We found that the decomposition increases linearly with the solid concentration (W): and that the kinetics are enhanced when the activated carbon specific area increases. We also conclude that the preozonation of the OSAC has no effect on its activity. We note that the temperature has a significant effect on the ozone decomposition rate even in the presence of OSAC. The value of the activation energy in the presence of the OSAC is lower than that obtained in homogeneous decomposition.     

Oil-Refinery Wastewater Treatment Aiming Reuse by Advanced Oxidation Processes (AOPs) Combined with Biological Activated Carbon (BAC)

The treatment of a refinery wastewater by Advanced Oxidation Processes (AOP) coupled with Biological Activated Carbon (BAC) was investigated aiming to generate water for reuse. O₃/UV and H₂O₂/UV processes were employed to oxidize the organic matter and the BAC process to remove residual organic matter from the AOP effluent. AOP promoted oxidation of recalcitrant organic matter as observed by moderate drops on the treated wastewater absorbance (31–79%) and TOC values (10–18%). BAC filters showed to be effective, reaching average efficiencies of 65% in a sufficiently long period of operation (84 days), while GAC filters were saturated after 28 days. Effluent TOC values in the range of 4 to 8.5 mg/L were achieved by the combined treatment (H₂O₂/UV + BAC), allowing water reuse.     

Removal of Color and Organic Matter in Industrial Phosphoric Acid by Ozone: Effect on Activated Carbon Treatment

Industrial phosphoric acid at 42-45% P₂O₅ and containing organic matter (OM) in the range of 220 mg/L to 300 mg/L is treated by combined ozonation and activated carbon. Ozonation alone removes the initial dark color of the acid and eliminates the organic content. Adsorption on activated carbon alone can reduce OM levels by 80% for more than 25 g/kg P₂O₅. We find that a preozonation noticeably enhances activated carbon efficiency and reduces its specific consumption. Isoconversion curves are plotted in specific ozone and activated carbon ratio space.