The Experts below are selected from a list of 14295 Experts worldwide ranked by ideXlab platform
Qian Zhao - One of the best experts on this subject based on the ideXlab platform.
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advanced treatment of biologically pretreated coal gasification wastewater by a novel integration of heterogeneous catalytic Ozonation and biological process
Bioresource Technology, 2014Co-Authors: Haifeng Zhuang, Qian ZhaoAbstract:Abstract Advanced treatment of biologically pretreated coal gasification wastewater (CGW) was investigated employing heterogeneous catalytic Ozonation integrated with anoxic moving bed biofilm reactor (ANMBBR) and biological aerated filter (BAF) process. The results indicated that catalytic Ozonation with the prepared catalyst (i.e. MnOx/SBAC, sewage sludge was converted into sludge based activated carbon (SBAC) which loaded manganese oxides) significantly enhanced performance of pollutants removal by generated hydroxyl radicals. The effluent of catalytic Ozonation process was more biodegradable and less toxic than that in Ozonation alone. Meanwhile, ANMBBR–BAF showed efficient capacity of pollutants removal in treatment of the effluent of catalytic Ozonation at a shorter reaction time, allowing the discharge limits to be met. Therefore, the integrated process with efficient, economical and sustainable advantages was suitable for advanced treatment of real biologically pretreated CGW.
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heterogeneous catalytic Ozonation of biologically pretreated lurgi coal gasification wastewater using sewage sludge based activated carbon supported manganese and ferric oxides as catalysts
Bioresource Technology, 2014Co-Authors: Haifeng Zhuang, Qian ZhaoAbstract:Abstract Sewage sludge of biological wastewater treatment plant was converted into sewage sludge based activated carbon (SBAC) with ZnCl 2 as activation agent, which supported manganese and ferric oxides as catalysts (including SBAC) to improve the performance of Ozonation of real biologically pretreated Lurgi coal gasification wastewater. The results indicated catalytic Ozonation with the prepared catalysts significantly enhanced performance of pollutants removal and the treated wastewater was more biodegradable and less toxic than that in Ozonation alone. On the basis of positive effect of higher pH and significant inhibition of radical scavengers in catalytic Ozonation, it was deduced that the enhancement of catalytic activity was responsible for generating hydroxyl radicals and the possible reaction pathway was proposed. Moreover, the prepared catalysts showed superior stability and most of toxic and refractory compounds were eliminated at successive catalytic Ozonation runs. Thus, the process with economical, efficient and sustainable advantages was beneficial to engineering application.
A Kettrup - One of the best experts on this subject based on the ideXlab platform.
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Ozonation of an azo dye c i remazol black 5 and toxicological assessment of its oxidation products
Chemosphere, 2003Co-Authors: Chunxia Wang, Ayfer Yediler, Doris Lienert, Zijian Wang, A KettrupAbstract:The effect of Ozonation (20.5 mg 1(-1)) on the degradation processes of an azo dye, Remazol Black 5 (RB5; Cl) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD5/28), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that Ozonation is a highly effective way to remove the colour of a corresponding dye solution. However, a considerable organic load still remained as indicated by high COD and TOC residues. The COD, TOC reductions were about 40% and 25% for 6 h Ozonation of 2 g 1(-1) RB5 aqueous solution. During the Ozonation process the rapid decrease of pH and the sharp increase of conductivity indicated the formation of acidic by-products and small fragments and ions which were identified by high performance ion chromatography. The BOD28 data revealed that first by-products after partial Ozonation (10-150 min) of RB5 were more biodegradable than the parent compound and Ozonation can enhance the biodegradability of azo dyes. During the first 150 min of total 360 min of oxidation, the formation of first by-products with high toxic potential took place as it could be confirmed by two acute toxicity-screening tests, the bioluminescence test (Vibrio fischerii) and the neutral red cytotoxicity assay (rat hepatoma cells). The significant enhancement of microbial biodegradability after long-term Ozonation could also be seen as a decrease of toxic intermediates in correlation with the Ozonation time as indicated in BOD28 biological degradation test results. (C) 2003 Elsevier Science Ltd. All rights reserved.
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Ozonation of an azo dye c i remazol black 5 and toxicological assessment of its oxidation products
Chemosphere, 2003Co-Authors: Chunxia Wang, Ayfer Yediler, Doris Lienert, Zijian Wang, A KettrupAbstract:The effect of Ozonation (20.5 mg 1(-1)) on the degradation processes of an azo dye, Remazol Black 5 (RB5; Cl) was studied. Conventional parameters such as chemical oxygen demand (COD), total organic carbon (TOC), pH, conductivity, colour removal, biodegradability (BOD5/28), and toxic potential of the dye and its degradation products were monitored during the process. The results obtained indicated that Ozonation is a highly effective way to remove the colour of a corresponding dye solution. However, a considerable organic load still remained as indicated by high COD and TOC residues. The COD, TOC reductions were about 40% and 25% for 6 h Ozonation of 2 g 1(-1) RB5 aqueous solution. During the Ozonation process the rapid decrease of pH and the sharp increase of conductivity indicated the formation of acidic by-products and small fragments and ions which were identified by high performance ion chromatography. The BOD28 data revealed that first by-products after partial Ozonation (10-150 min) of RB5 were more biodegradable than the parent compound and Ozonation can enhance the biodegradability of azo dyes. During the first 150 min of total 360 min of oxidation, the formation of first by-products with high toxic potential took place as it could be confirmed by two acute toxicity-screening tests, the bioluminescence test (Vibrio fischerii) and the neutral red cytotoxicity assay (rat hepatoma cells). The significant enhancement of microbial biodegradability after long-term Ozonation could also be seen as a decrease of toxic intermediates in correlation with the Ozonation time as indicated in BOD28 biological degradation test results. (C) 2003 Elsevier Science Ltd. All rights reserved.
Rafael R Solis - One of the best experts on this subject based on the ideXlab platform.
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clopyralid degradation using solar photocatalytic ozone process with olive stone activated carbon
Journal of environmental chemical engineering, 2019Co-Authors: Zouhour Rajah, Rafael R Solis, Javier F Rivas, Monia Guiza, Nidhal Becheikh, Abdelmottaleb OuederniAbstract:Abstract Clopyralid degradation in ultrapure water was investigated by homogeneous Ozonation (O3), catalytic Ozonation with Olive Stone Activated Carbon (O3/OSAC), under simulated sunlight radiation by photolytic Ozonation (O3/Daylight) and photocatalytic Ozonation (O3/OSAC/Daylight). The OSAC was characterized by several analytical techniques, such as Nitrogen adsorption desorption at 77 K, Scanning Electron Microscopy (SEM-EDX), determination of pHpzc and X-ray Photoelectron Spectroscopy (XPS). This herbicide exhibited a rapid oxidation rate in the simultaneous presence of ozone, activated carbon and simulated sunlight. The combined process led to a complete removal of clopyralid in less than 30 min. Solar-photocatalytic Ozonation was the most efficient process both in terms of clopyralid elimination rate and mineralization. Clopyralid degradation mainly occurs through hydroxyl radical in those systems involving ozone. For comparison purposes, the different processes can be modelled by simple first-order kinetics in clopyralid concentration (rate constants khomo = 0.0159 min−1, homogeneous Ozonation; kO3/Daylight = 0.0410 min−1, kO3/OSAC = 0.0705 min−1, kO3/OSAC/Daylight = 0.1433 min−1). 90% of Total Organic Carbon (TOC) removal after 3 h was reached in photocatalytic Ozonation (O3/OSAC/Daylight) and photolytic Ozonation (O3/Daylight) compared to about 70% using O3/OSAC. Single Ozonation just led to 20% TOC reduction under similar operating conditions. Furthermore, small oxygenated organic and inorganic by-products were analyzed by ionic chromatography. As a rule of thumb, TOC removal led to the formation of low weight carboxylic acids, taking place the release of chlorides and nitrates. Finally, toxicity evolution during O3, O3/OSAC, O3/Daylight and O3/OSAC/Daylight were monitored considering phytotoxicity trials of Lactuca Sativa germination. Phytotoxicity assays indicate almost total detoxification after the photocatalytic Ozonation treatment.
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photocatalytic Ozonation of clopyralid picloram and triclopyr kinetics toxicity and influence of operational parameters
Journal of Chemical Technology & Biotechnology, 2016Co-Authors: Rafael R Solis, Olga Gimeno, Javier F Rivas, Jose Luis PerezboteAbstract:BACKGROUND Photolysis, photocatalysis, Ozonation and photocatalytic Ozonation in the presence of titania have been applied to the elimination of three pyridine carboxylic acids herbicides (clopyralid, picloram and triclopyr) in water. RESULTS Photocatalytic Ozonation led to the best results in terms of herbicide elimination rate and mineralization. The herbicides were relatively recalcitrant to direct Ozonation (rate constants: 20 M−1 min−1 for clopyralid and triclopyr, and 105 M−1 min−1 in the case of picloram). Herbicides degradation proceeds by hydroxyl radicals attack (rate constants: 0.73, 3.80 and 1.73 × 109 M−1 s−1 for clopyralid, picloram and triclopyr, respectively). Monitoring of chloride and nitrates suggests dechlorination as the primary stage in the process. Further ring opening led to the accumulation of nitrates and the appearance of some low weight carboxylic acids. Toxicity decreased at the end of the process. CONCLUSION Tested herbicides slowly react with ozone. Photocatalytic Ozonation shows different degrees of synergism, leading to 80% mineralization in less than 1 h. Small amounts of TiO2 (i.e. 0.005 g L−1) maintains the efficiency of the photocatalytic Ozonation. Quantitative free chloride and nitrates rapidly appear in the O3/UVA/TiO2 system. First intermediates in the photocatalytic Ozonation of clopyralid show higher toxicity than the parent compound. © 2014 Society of Chemical Industry
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Ozonation, photocatalysis and photocatalytic Ozonation of diuron. Intermediates identification
Chemical Engineering Journal, 2016Co-Authors: Rafael R Solis, F. Javier Rivas, Ana B. Martínez-piernas, Ana AgüeraAbstract:Abstract Aqueous 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron) has been oxidized by Ozonation, photocatalysis and photocatalytic Ozonation. Diuron degradation takes place via radical pathway through hydroxyl radicals in those systems involving ozone. Diuron elimination in photocatalytic Ozonation is not enhanced if compared to single Ozonation; however, TOC removal was significantly improved. Specifically, 80% TOC removal in 2 h was reached in photocatalytic Ozonation while single Ozonation just led to 25% TOC reduction. Photocatalysis required 9 h to reach 25% TOC reduction. Ten transformation by-products generated during the application of the three technologies were tentatively identified by liquid chromatography–quadrupole time-of-flight mass spectrometry (LC–QTOF–MS/MS). Single Ozonation and photocatalytic Ozonation led to the formation and complete elimination of all by-products. Low weight carboxylic acids evolution suggests that high TOC removal in photocatalytic Ozonation is linked to its capacity to oxidize small oxygenated compounds and release of inorganic chloride and nitrate. Toxicity evolution to Vibrio fischeri in photocatalytic Ozonation displayed an increase in inhibition at the initial stages (>90% of inhibition), followed by a decrease of this parameter as the reaction progressed. The final treated sample shows a lower toxicity than the initial one (55% vs 20%).
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Photocatalytic Ozonation of clopyralid, picloram and triclopyr. Kinetics, toxicity and influence of operational parameters
Journal of Chemical Technology & Biotechnology, 2014Co-Authors: Rafael R Solis, Olga Gimeno, F. Javier Rivas, José Luis Pérez-boteAbstract:BACKGROUND Photolysis, photocatalysis, Ozonation and photocatalytic Ozonation in the presence of titania have been applied to the elimination of three pyridine carboxylic acids herbicides (clopyralid, picloram and triclopyr) in water. RESULTS Photocatalytic Ozonation led to the best results in terms of herbicide elimination rate and mineralization. The herbicides were relatively recalcitrant to direct Ozonation (rate constants: 20 M−1 min−1 for clopyralid and triclopyr, and 105 M−1 min−1 in the case of picloram). Herbicides degradation proceeds by hydroxyl radicals attack (rate constants: 0.73, 3.80 and 1.73 × 109 M−1 s−1 for clopyralid, picloram and triclopyr, respectively). Monitoring of chloride and nitrates suggests dechlorination as the primary stage in the process. Further ring opening led to the accumulation of nitrates and the appearance of some low weight carboxylic acids. Toxicity decreased at the end of the process. CONCLUSION Tested herbicides slowly react with ozone. Photocatalytic Ozonation shows different degrees of synergism, leading to 80% mineralization in less than 1 h. Small amounts of TiO2 (i.e. 0.005 g L−1) maintains the efficiency of the photocatalytic Ozonation. Quantitative free chloride and nitrates rapidly appear in the O3/UVA/TiO2 system. First intermediates in the photocatalytic Ozonation of clopyralid show higher toxicity than the parent compound. © 2014 Society of Chemical Industry
Zhonglin Chen - One of the best experts on this subject based on the ideXlab platform.
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catalytic Ozonation benefit from the enhancement of electron transfer by the coupling of g c3n4 and lacoo3 discussion on catalyst fabrication and electron transfer pathway
Applied Catalysis B-environmental, 2019Co-Authors: Yuting Zhang, Zilong Song, Chao Liu, Yujin Long, Jiawei Zou, Longyan Liu, Zhonglin ChenAbstract:Abstract In this study, the novel design approach of catalyst in catalytic Ozonation was proposed to enhance electron transfer in catalytic Ozonation, achieving a better performance on micro-pollutants degradation and bromate elimination. The combination of perovskite oxide (LaCoO3, LCO) and graphitic carbon nitride (g-C3N4, CN) was studied to overcome some significant drawbacks of catalytic Ozonation with metal oxides catalysts, such as the rate-limiting step between Men+ and Me(n+m)+. Additionally, the in-depth analysis of electron transfer pathway in CN/LCO catalytic Ozonation was provided, which provided new insight into the design of highly efficient catalysts for facilitating micro-pollutants degradation and bromate inhibition. CN/LCO was successfully prepared and connected by the formation of -C-O-Co linkages, which exhibited a high activity in the catalytic Ozonation for the synchronous degradation of benzotriazole (BZA) and elimination of bromate. Interestingly, being different with the general mechanism of catalytic Ozonation, nitrogen vacancies and -C-O-Co bonds were the main active sites in CN/LCO rather than the surface hydroxyl group. With the largest amount of -C-O-Co and more nitrogen defects, CN/LCO exhibited a fast charge transfer along the in-plane direction. Additionally, the fast reduction of Co3+ to Co2+ was found to be initialized by O2•− and single electrons in catalytic Ozonation, which resulted in more formation of H2O2 and good inhibition efficiency of bromate. This study not only present the good catalytic Ozonation ability for refractory organic micro-pollutants and elimination of bromate using CN/LCO, but also provided insight into electron transfer pathway in the interlayers of CN/LCO, which will be significant for the design of catalyst and to promote charge transfer in catalytic Ozonation.
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synchronously degradation benzotriazole and elimination bromate by perovskite oxides catalytic Ozonation performance and reaction mechanism
Separation and Purification Technology, 2018Co-Authors: Yuting Zhang, Fei Qi, Bingbing Xu, Qingwei Li, Zhonglin ChenAbstract:Abstract Ozonation showed a good capacity on micro-emerging pollutants degradation from water or wastewater treatment, but its leading to the formation of toxic bromate. Bromate inhibition in catalytic Ozonation treatment remained an important challenge. In this study, a novel catalytic Ozonation was promoted using perovskite oxide as catalyst, showing good performance on synchronously degradation benzotriazole (BZA) and elimination bromate. LaCoO3 exhibited significant catalytic activity for BZA degradation, with complete degradation achieved at 15 min, and about 71% BrO3− inhibition, compared with single Ozonation. LaFeO3 showed no catalytic activity for BZA degradation but inhibited the generation of BrO3− by 73%. Further investigation involving reactive oxygen species, important intermediates, the structure and surface chemical properties of the catalysts showed that H2O2 act an important effect but various in different Ozonation systems. The combination of the surface hydroxyl groups on LaFeO3 with H2O2 to form [Fe-H2O2]s was found to occur in LaFeO3 catalytic Ozonation, resulting the reduction of BrO3−. The production of ROS in LaCoO3 catalytic system and the cyclic of Co3+/Co2+ accelerated the BZA degradation efficiency and inhibition of BrO3−. A novel BrO3− elimination pathway was proposed, as an important contribution for the application of catalytic Ozonation.
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enhanced Ozonation of dichloroacetic acid in aqueous solution using nanometer zno powders
Journal of Environmental Sciences-china, 2010Co-Authors: Xu Zhai, Zhonglin Chen, Shuqing Zhao, He Wang, Lei YangAbstract:Nanometer zinc oxide (ZnO) powders were used as a catalyst to enhance the Ozonation for the degradation of dichloroacetic acid (DCAA) in aqueous solution. The batch experiments were carried out to investigate the effects of key factors such as catalyst dosage, ozone dosage, solution pH and tert-butyl alcohol (t-BuOH) on the degradation efficiency of DCAA. Density functional theory (DFT) was adopted to explore the mechanism of generating hydroxyl radical (*OH) on the ZnO surface. The results showed that adsorption and Ozonation processes were not effective for DCAA removal, and the addition of ZnO catalyst improved the degradation efficiency of DCAA during Ozonation, which caused an increase of 22.8% for DCAA decomposition compared to the case of Ozonation alone after 25 min. Under the same experimental conditions, the DCAA decomposition was enhanced by increasing catalyst dosage from 100 to 500 mg/L and ozone dosage from 0.83 to 3.2 mg/L. The catalytic Ozonation process is more pronounced than the Ozonation process alone at pH 3.93, 6.88, and 10. With increasing the concentration of t-BuOH from 10 to 200 mg/L, the degradation of DCAA was significantly inhibited in the process of catalytic Ozonation, indicating that ZnO catalytic Ozonation followed *OH reaction mechanism. Based on the experimental results and DFT analysis, it is deduced that the generation of *OH on the ZnO surface is ascribed to the adsorption of molecule ozone followed by the interaction of adsorbed ozone with active sites of the catalyst surface. It is also concluded that ZnO may be an effective catalyst for DCAA removal, which could promote the formation of *OH derived from the catalytic decomposition of ozone.
Fengqiang Sun - One of the best experts on this subject based on the ideXlab platform.
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catalytic Ozonation of p chlorobenzoic acid by activated carbon and nickel supported activated carbon prepared from petroleum coke
Journal of Hazardous Materials, 2009Co-Authors: Qiuyun Zhang, Lili Tang, Fengqiang SunAbstract:The aim of this research was to investigate catalytic activity of petroleum coke, activated carbon (AC) prepared from this material, Ni supported catalyst on activated carbon (Ni/AC) in the Ozonation of aqueous phase p-chlorobenzoic acid (p-CBA). Activated carbon and Ni/AC catalyst were characterized by XRD and SEM. The presence of petroleum coke did not improve the degradation of p-CBA compared to Ozonation alone, but it was advantageous for p-CBA mineralization (total organic carbon, TOC, reduction), indicating the generation of highly oxidant species (*OH) in the medium. The presence of either activated carbon or Ni/AC considerably improves TOC removal during p-CBA Ozonation. Ni/AC catalyst shows the better catalytic activity and stability based on five repeated tests during p-CBA Ozonation. During the Ozonation (50 mg/h ozone flow rate) of a 10 mg/L p-CBA (pH 4.31), it can be more mineralized in the presence of Ni/AC catalyst (5.0 g/L), TOC removal rate is over 60% in 60 min, 43% using activated carbon as catalyst, only 30% with Ozonation alone.
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catalytic Ozonation of p chlorobenzoic acid by activated carbon and nickel supported activated carbon prepared from petroleum coke
Journal of Hazardous Materials, 2009Co-Authors: Qiuyun Zhang, Lili Tang, Fengqiang SunAbstract:The aim of this research was to investigate catalytic activity of petroleum coke, activated carbon (AC) prepared from this material, Ni supported catalyst on activated carbon (Ni/AC) in the Ozonation of aqueous phase p-chlorobenzoic acid (p-CBA). Activated carbon and Ni/AC catalyst were characterized by XRD and SEM. The presence of petroleum coke did not improve the degradation of p-CBA compared to Ozonation alone, but it was advantageous for p-CBA mineralization (total organic carbon, TOC, reduction), indicating the generation of highly oxidant species ( • OH) in the medium. The presence of either activated carbon or Ni/AC considerably improves TOC removal during p-CBA Ozonation. Ni/AC catalyst shows the better catalytic activity and stability based on five repeated tests during p-CBA Ozonation. During the Ozonation (50 mg/h ozone flow rate) of a 10 mg/L p-CBA (pH 4.31), it can be more mineralized in the presence of Ni/AC catalyst (5.0 g/L), TOC removal rate is over 60% in 60 min, 43% using activated carbon as catalyst, only 30% with Ozonation alone. © 2008 Elsevier B.V. All rights reserved.
