臭氧氧化法处理化工废水工艺优化及性能评价

研究了臭氧氧化法对两种典型的化工废水(煤气化废水(CGW)和聚合母液废水(PMLW))的降解效果,对臭氧化的工艺条件进行了优化。结果表明,臭氧可有效处理富含高浓度、有毒、难降解酚类煤气化废水。在最优工艺条件(臭氧浓度为50 mg/L,氧化降解60 min,初始pH值11)处理CGW,COD从1 075 mg/L降至362 mg/L。废水颜色从棕色浑浊变成无色透明,可生化性显著提高。对于聚合母液废水,分析了臭氧浓度、串联反应器的串联级数、降解时间对COD去除率的影响。分析比较了串联反应器级数和臭氧浓度对臭氧化效率的影响。结果表明,以反应速率和COD去除率为目标,在优化工艺条件下(臭氧浓度为60 mg/L,降解150 min,3、5级串联),COD去除率可达66.4%。对串联反应器,高浓度臭氧虽可提高COD去除率和降解速率,但臭氧利用效率降低;五级串联臭氧利用效率是三级的2倍,增加级数可提高臭氧利用效率。两类化工废水臭氧化降解实验表明,臭氧浓度对COD降解具有饱和性,反应过程在临界时间点可分为快速和慢速反应两阶段性。     

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。     

臭氧氧化法处理化工废水工艺优化及性能评价

研究了臭氧氧化法对两种典型的化工废水(煤气化废水(CGW)和聚合母液废水(PMLW))的降解效果,对臭氧化的工艺条件进行了优化。结果表明,臭氧可有效处理富含高浓度、有毒、难降解酚类煤气化废水。在最优工艺条件(臭氧浓度为50 mg/L,氧化降解60 min,初始pH值11)处理CGW,COD从1 075 mg/L降至362 mg/L。废水颜色从棕色浑浊变成无色透明,可生化性显著提高。对于聚合母液废水,分析了臭氧浓度、串联反应器的串联级数、降解时间对COD去除率的影响。分析比较了串联反应器级数和臭氧浓度对臭氧化效率的影响。结果表明,以反应速率和COD去除率为目标,在优化工艺条件下(臭氧浓度为60 mg/L,降解150 min,3、5级串联),COD去除率可达66.4%。对串联反应器,高浓度臭氧虽可提高COD去除率和降解速率,但臭氧利用效率降低;五级串联臭氧利用效率是三级的2倍,增加级数可提高臭氧利用效率。两类化工废水臭氧化降解实验表明,臭氧浓度对COD降解具有饱和性,反应过程在临界时间点可分为快速和慢速反应两阶段性。     

臭氧氧化降解水中双酚A的研究

随着科技的进步,对环境造成的危害也不断加剧,其中有机污染物双酚A,可能导致内分泌失调,威胁着胎儿和儿童的健康,降解双酚A对于研学理界非常重要。本文对臭氧氧化降解双酚A影响因素进行分析研究,考察了溶液p H值、反应时间、双酚A初始浓度、反应温度和臭氧量等物化参数对臭氧氧化降解模拟双酚A废水效率的影响,同时对双酚A降解机理进行了研究。结果表明,臭氧氧化降解双酚A的最佳条件为:温度25℃,初始浓度100 mg/L,p H值6.6,臭氧投加量12 mg/min,反应时间75min。且臭氧氧化双酚A的过程为臭氧的直接氧化。该研究为臭氧的工业化生产及人们的生产生活应用提供理论依据。     

泡沫铁催化臭氧氧化水中诺氟沙星

诺氟沙星作为一种典型抗生素被广泛使用,但是其在水环境中难以被自然降解。试验选用泡沫铁作为催化剂,催化臭氧氧化去除水中的诺氟沙星。以水样的总有机碳(TOC)去除率作为主要指标,通过单因素试验研究了泡沫铁催化臭氧反应体系的主要影响因素和最佳反应条件。结果表明:与单独臭氧氧化比较,添加泡沫铁作为催化剂可以有效提高TOC的去除率,在催化剂投加量为79.5 g/L、臭氧浓度为9.0 mg/L、初始诺氟沙星浓度为30 mg/L和pH值为7时,60 min后诺氟沙星的去除率可以达到75.9%,比单独臭氧氧化作用提高了44.0%。将NaHCO_3作为自由基抑制剂加入反应体系,可明显降低诺氟沙星的去除率,间接证明了该反应遵循自由基机理。     

硅铁合金催化臭氧氧化水中布洛芬

近几年,在各地的饮用水中不断检测到微量布洛芬,其环境毒性引起了广泛关注。选用工业硅铁作为催化剂,催化臭氧氧化去除水中的布洛芬,并通过单因素试验,确定了反应体系的最佳条件。结果表明,在硅铁的作用下,催化臭氧氧化可以明显提高布洛芬的去除率。在硅铁投加量为1 g/L、水溶液初始pH值为8、臭氧浓度9.0 mg/L、布洛芬初始浓度为10 mg/L时,经过80 min,水样总有机碳(TOC)的去除率可达75.5%,较单独臭氧氧化提高了38.0%。将碳酸氢钠作为自由基抑制剂加入反应体系,可明显降低TOC的去除率,间接证明了催化臭氧氧化布洛芬的反应遵循自由基机理。     

高铁酸盐和臭氧氧化法降解水中双酚A的研究

通过烧杯试验,对比研究了不同因素对高铁酸盐和臭氧氧化降解双酚A的影响,并对试验过程中的生物毒性进行了对比分析。试验结果表明:针对质量浓度为1 mg/L的双酚A模拟废水,在高铁酸盐和臭氧的投加量分别为5.0和1.20 mg/L的条件下,高铁酸盐降解双酚A的能力更强,去除率达到91.6%,而臭氧氧化法仅为80.9%;同时,高铁酸盐法具有更广的pH值(3~11)和温度(10~50℃)适应性。不同的干扰离子对氧化体系的影响不同,HCO3-对2个氧化体系均具有一定的促进作用;Fe3+的存在具有催化作用,有利于臭氧氧化降解双酚A,但是不利于高铁酸盐的稳定性从而不利于双酚A的脱除。2种方法处理后水的生物毒性均随反应时间的延长呈先升高后降低的趋势,相对而言,高铁酸盐法对处理后水的毒性控制效果更佳。     

镍铁层状双金属氢氧化物催化臭氧去除双酚A的试验

采用共沉淀的方法合成镍铁层状双金属氢氧化物,通过X射线衍射(XRD)研究不同镍铁金属摩尔比例对镍铁层状双金属氢氧化物晶型的影响;设计单因素试验,研究催化剂投加量、pH、臭氧浓度、镍铁金属摩尔比例等因素对双酚A(BPA)去除效果的影响;探讨催化臭氧氧化去除BPA的反应机理。XRD图显示当镍铁金属摩尔比为3∶1时,镍铁层状双金属氢氧化物的结晶度最好。试验结果表明:在BPA初始浓度为10 mg/L、pH值为8.2、臭氧浓度为9.0 mg/L、催化剂投加量为0.3 g/L、镍铁金属摩尔比例为3∶1的条件下,含BPA废水的总有机碳(TOC)去除率高达89%。通过羟基自由基抑制剂反应试验,观察到TOC和BPA的去除率均有所降低,说明催化臭氧反应过程中存在羟基自由基氧化作用。     

CuCe氧化物催化剂的制备及CWPO降解双酚A废水研究

为解决Fenton法存在活性组分流失及通常在pH 2～3条件下运行的局限性，采用柠檬酸络合法制备了CuCe氧化物催化剂，建立了双酚A非均相催化湿式过氧化氢氧化（CWPO）反应体系。考察了焙烧温度、Cu/Ce摩尔比、H₂O₂用量、双酚A初始浓度和pH对催化剂物化结构和CWPO性能的影响。并分析了可能的降解路径。结果表明：催化剂具有良好的高温稳定性和pH适应性，在pH 1.6～7.9范围内对双酚A都具有较高的降解性能，不需要调节pH。在焙烧温度450℃、Cu/Ce摩尔比1.0、催化剂用量1 g·L^-1、H₂O₂用量196 mmol·L^-1、BPA浓度152 mg·L^-1、pH 6.6、反应温度75℃、反应95 min后，BPA和TOC去除率分别为91.8%和84.5%,Cu²⁺析出浓度为19.3 mg·L^-1。推测了双酚A可能的降解路径。     

磁力搅拌/臭氧法降解对氨基苯酚模拟废水的研究

采用磁力搅拌/臭氧法降解含对氨基苯酚模拟废水,研究了影响对氨基苯酚模拟废水降解的各因素,考察了反应液初始浓度、初始p H、臭氧投量、反应温度、常见无机离子等因素对臭氧氧化降解对氨基苯酚反应速率的影响。结果表明,在25℃、p H=4.52、初始质量浓度为100 mg/L、臭氧投加量为50 L/h,反应30 min时,对氨基酚的去除率达95.2%,盐的存在不同程度地降低了臭氧降解效果。     

Ozonation of a mixture of dialkylphthalates in aqueous solution

Ozonation of dimethyl phthalate, diethyl phthalate and dipropyl phthalate was carried out to evaluate the potential of ozonation for phthalate removal from water. Phthalates with longer alkyl chains, which are often more resistant to biodegradation were found to be more degradable than those with shorter alkyl chains. The degradation of phthalates by ozonation follows the pseudo‐first‐order kinetic model. The rate of phthalates degradation increased exponentially with increasing temperature in the range studied (20 to 50 °C) and in proportion with applied ozone dosages. The rate of phthalates degradation was found to increase with increasing pH of the solution from 2.6 to 11.0, and decreased exponentially with increasing initial concentrations of the phthalates. Degradation of phthalates via ozonation was found to develop dominantly through direct reaction with hydroxyl radicals. Copyright © 2010 Society of Chemical Industry     

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).     

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。     

Catalytic decomposition of ozone and para-Chlorobenzoic acid (pCBA) in the presence of nanosized ZnO

This research forwards the evaluating of the efficiency of nanosized ZnO in the application of the catalytic ozonation, determines the reaction kinetics of ozone with the nanosized ZnO, and delineates the characteristics of the decomposition of para-Chlorobenzoic acid (pCBA) and ozone in catalytic ozonation using the nanosized ZnO particles. It was found that the nanosized ZnO enhanced the degradation of ozone and the catalytic ozonation on the surface of the nanosized ZnO significantly enhanced the degradation of pCBA. In catalytic reactions the degradation of pCBA followed two-stage kinetics, initial rapid removal phase (Phase I) and a slower decomposition phase (Phase II). The total degradation rate of pCBA was well matched with the initial removal of pCBA in Phase I. The R_ct values representing the ratio of hydroxyl radicals [OH] and ozone [O₃] were found to increase with an increased concentration of the nanosized ZnO indicating the enhanced transformation of ozone into OH.     

Ozonation of chloronitrobenzenes in aqueous solution: kinetics and mechanism

BACKGROUND: Chloronitrobenzenes (ClNBs) are a family of toxic and bio‐resistant organic compounds. Ozone treatment is specifically suitable for partial or complete oxidation of non‐biodegradable components. However, few studies on the decomposition of ClNBs by ozone are available, and kinetics and mechanisms of ClNBs ozonation have not been thoroughly investigated. The kinetics and mechanism of ozonation degradation of ClNBs in aqueous solution were investigated, and the contribution of both molecular ozone and hydroxyl radicals was also evaluated. RESULTS: The results demonstrated that the decomposition of ClNBs was a pseudo‐first‐order reaction with respect to the pollutant concentration and the overall rate constant increased with an increase in pH. It declined, however, with an increase in pollutant and radical scavenger concentration. Furthermore, TOC removal rate was significantly lower than that of ClNBs, but the same order o‐ClNB < m‐ClNB < p‐ClNB was followed. Ozonation could not reduce TOC significantly, p‐chlorophenol, p‐nitrophenol, 2‐chloro‐5‐nitrophenol and 5‐chloro‐2‐nitrophenol were detected as primary degradation intermediates in ozonation of p‐ClNB. Rate constants of the direct reaction between ozone and ClNBs at 25 °C had been found to be lower than 1 M^?1S^?1. More than 95% of ClNBs removal was due to hydroxyl radical oxidation at pH ≥ 7. CONCLUSION: Advanced oxidation processes may be the preferred choice for the elimination of ClNBs from the environment. Copyright © 2008 Society of Chemical Industry     

氯代硝基苯类废水臭氧化动力学和机理

采用半连续臭氧化工艺处理氯代硝基苯类废水,对氯代硝基苯（ClNBs）臭氧化过程反应动力学、臭氧分子与自由基氧化反应的贡献、过程降解机理等方面进行了研究。结果表明,ClNBs降解遵循准一级反应动力学,降解速率顺序为o-CNB相似文献   

DECOMPOSITION OF 4-NITROPHENOL BY OZONATION IN A HOLLOW FIBER MEMBRANE REACTOR

The effect of initial pH, liquid flow rate, gas flow rate, and gaseous ozone concentration on the ozonation of 4-nitrophenol in a membrane reactor was investigated. The results showed that the disappearance of 4-nitrophenol increased with the increase of liquid flow rate, gas flow rate, and gaseous ozone concentration. The rise of the initial pH value led to an increase in 4-nitrophenol removal rate, but the increase became negligible after initial pH exceeded 9.5. The highest removal efficiency of 4-nitrophenol achieved was 94% after 100 min reaction when gaseous ozone concentration was 0.51 mmol L^?1, gas flow rate was 57 mL min^?1, liquid recirculation rate was 72 mL min^?1, and initial pH was 10.3. The membrane reaction system could be modeled based on the lumped kinetics of 4-nitrophenol removal, and the corresponding rate constant of 4-nitrophenol removal was determined from the model.     

2，4-二氯苯氧乙酸臭氧化过程中过氧化氢的生成

引言2,4-二氯苯氧乙酸(2,4-D,又名2,4-滴)是一种广泛使用的除草剂[1],应用历史较长,是我国主要的除草剂品种之一,用量也比较大。2,4-D属于苯氧羧酸类除草剂的一种,可有效去除阔叶杂草,目前仍广泛用于农作物除草和草坪养护[2]。2,4-D的水溶性较高,挥发性较低,在自然界中难以生物     

Ozone treatment of textile effluents and dyes: effect of applied ozone dose,pH and dye concentration

The ozonation of wastewater supplied from a treatment plant (Samples A and B) and dye‐bath effluent (Sample C) from a dyeing and finishing mill and acid dye solutions in a semi‐batch reactor has been examined to explore the impact of ozone dose, pH, and initial dye concentration. Results revealed that the apparent rate constants were raised with increases in applied ozone dose and pH, and decreases in initial dye concentration. While the color removal efficiencies of both wastewater Samples A and C for 15 min ozonation at high ozone dosage were 95 and 97%, respectively, these were 81 and 87%, respectively at low ozone dosage. The chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal efficiencies at several ozone dose applications for a 15 min ozonation time were in the ranges of 15–46% and 10–20%, respectively for Sample A and 15–33% and 9–19% respectively for Sample C. Ozone consumption per unit color, COD and DOC removal at any time was found to be almost the same while the applied ozone dose was different. Ozonation could improve the BOD₅ (biological oxygen demand) COD ratio of Sample A by 1.6 times with 300 mg dm^?3 ozone consumption. Ozonation of acid dyes was a pseudo‐first order reaction with respect to dye. Increases in dye concentration increased specific ozone consumption. Specific ozone consumption for Acid Red 183 (AR‐183) dye solution with a concentration of 50 mg dm^?3 rose from 0.32 to 0.72 mg‐O₃ per mg dye decomposed as the dye concentration was increased to 500 mg dm^?3. © 2002 Society of Chemical Industry