Catalytic technologies have been paid increasing attention in refractory pollutants abatement due to its practical and potential values in water purification. As effective and efficient approaches for water purificati...Catalytic technologies have been paid increasing attention in refractory pollutants abatement due to its practical and potential values in water purification. As effective and efficient approaches for water purification, Fenton's reagent, ozonation, electrochemical and photocatalytic methods have been widely studied and applied in different aspects and have been reviewed by several articles. In recent years, some novel catalytic processes based on above processes have been developed for enhancing the efficiency of removing the organics from water. This review emphasized on the recent development of heterogeneous catalytic ozonation, electrocatalysis in respect of novel electrodes and electro-Fenton method, photoelectrocatalysis process and photoelectron-Fenton in water purification. It was also an attempt to propose general ideas about mechanism and principle enhancing the catalytic efficiency for the degradation and the mineralization of organics in water.展开更多
The degradation of nitrobenzene by ceramic-honeycomb catalyzed ozonation was investigated. The results showed that the presence of ceramic honeycombs significantly increased the oxidation rate of nitrobenzene by ozone...The degradation of nitrobenzene by ceramic-honeycomb catalyzed ozonation was investigated. The results showed that the presence of ceramic honeycombs significantly increased the oxidation rate of nitrobenzene by ozone compared to the case of ozone oxidation alone. In this paper, the effects of various factors on the catalytic oxidation were investigated, such as the amount of catalysts, the ozone dosage, the temperature, the pH value and the presence of tert-butanol. With the addition of tert-butanol the removal of nitrobenzene decreased sharply, which appeared to support that, the degradation of nitrobenzene by ozonation followed a radical type mechanism. The EPR experiments verified that higher nitrobenzene removal rate was attributed to more OH radicals generated in the catalyzed ozonation than ozonation alone.展开更多
Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental ...Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental results indicate that Cu/Al2O3 has a very effective catalytic activity during the ozonation of organic pollutants in water. The optimum conditions for preparing Cu/Al2O3 were systematically investigated with the orthogonal testing method. Furthermore, the results also show that the surface properties of catalyst are not compulsory for effective oxidation.展开更多
This paper describes the potential of heterogeneous catalytic ozonization of sulfo-salicylic acid (SSal). It was found that catalytic ozonization in the presence of Mn-Zr-O (a modified manganese dioxide supported on ...This paper describes the potential of heterogeneous catalytic ozonization of sulfo-salicylic acid (SSal). It was found that catalytic ozonization in the presence of Mn-Zr-O (a modified manganese dioxide supported on silica gel) had significantly enhanced the removal rate (72%) of total organic carbon (TOC) compared with that of ozonization alone (19%). The efficient removal rate of TOC was probably due to increasing the adsorption ability of catalyst and accelerating decomposition of ozone to produce more powerful oxidants than ozone. .展开更多
Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)wa...Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)was pretreated with 10%H_(2)SO_(4)by single factor optimization to increase specific surface area and pore volume obviously.The catalytic ozonation performance of ACF loaded with Au,Ag,Pt and Pd noble metals on ethyl acetate was investigated and Pd/ACF was selected as the optimal catalyst which had certain stability.Pd is uniformly distributed on the surface of ACF,and Palladium mainly exists in the form of Pd0 with a amount of Pd+2.The specific surface area of the catalysts gradually decreases as the loading increases.The activation energy of ethyl acetate calculated by Arrhenius equation is 113 kJ mol 1.With 1%Pd loading and the concentration ratio of ozone to ethyl acetate is 3:1,catalytic ozonation performance is maximized and the conversion rate of ethyl acetate reached to 60%in 3050℃Cat 15,00030,000 h^1.展开更多
CuO particles were attempted to fill in the channel of multi-walled carbon nanotubes (MWCNTs) as novel catalytic materials CuO@MWCNTs used for ozonation of humic acids (HA) in aqueous solution.Catalyst samples were ch...CuO particles were attempted to fill in the channel of multi-walled carbon nanotubes (MWCNTs) as novel catalytic materials CuO@MWCNTs used for ozonation of humic acids (HA) in aqueous solution.Catalyst samples were characterized by transmission electron microscopy (TEM),X-ray diffraction (XRD),thermogravimetric analysis (TG) and X-ray photoelectron spectroscopy (XPS).The removal efficiency of HA was promoted in the presence of CuO@MWCNTs compared with that of Al2O3-supported CuO catalyst (CuO/Al2O3) and CuO-coating MWCNTs catalyst (CuO/MWCNTs).The strong synergetic effect in the confinement environment on CuO nanoparticles can attribute to the locally higher pressure due to the lower potential energy of reactants in the channels.Strong interaction happened between the catalyst and reactants,which promoted the decomposition of ozone and the generation of OH.The results of experimental and theoretical investigation confirmed that CuO@MWCNTs promotes the initiation and generation of OH,hence accelerating the degradation of organic pollutants.展开更多
To improve the sludge conditioning efficiency without increasing the ozone dose,an in-situ sludge reduction process based on Mn^(2+)-catalytic ozonation conditioning was proposed.Using ozone conditioning alone as a co...To improve the sludge conditioning efficiency without increasing the ozone dose,an in-situ sludge reduction process based on Mn^(2+)-catalytic ozonation conditioning was proposed.Using ozone conditioning alone as a control,a lab-scale sequencing batch reactor coupled with ozonated sludge recycle was evaluated for its operating performance at an ozone dose of 75 mg O_(3)/g VSS and 1.5 mmol/L Mn^(2+)addition.The results showed a 39.4%reduction in MLSS and an observed sludge yield of 0.236 kg MLSS/kg COD for the O_(3)+Mn^(2+)group compared to the O_(3)group (15.3%and 0.292 kg MLSS/kg COD),accompanied by better COD,NH_(4)^(+)-N,TN and TP removal,improved effluent SS and limited impact on excess sludge properties.Subsequently,activity tests,BIOLOG ECO microplates and 16S rRNA sequencing were applied to elucidate the changing mechanisms of Mn^(2+)-catalytic ozonation related to microbial action:(1) Dehydrogenase activity reached a higher peak.(2) Microbial utilization of total carbon sources had an elevated effect,up to approximately 18%,and metabolic levels of six carbon sources were also increased,especially for sugars and amino acids most pronounced.(3) The abundance of Defluviicoccus under the phylum Proteobacteria was enhanced to 12.0%and dominated in the sludge,they had strong hydrolytic activity and metabolic capacity.Denitrifying bacteria of the genus Ferruginibacter also showed an abundance of 7.6%,they contributed to the solubilization and reduction of sludge biomass.These results could guide researchers to further reduce ozonation conditioning costs,improve sludge management and provide theoretical support.展开更多
In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K...In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.展开更多
Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The exper...Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance (EPR) experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.展开更多
MnxCe1- xO2(x: 0.3–0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde(HCHO). At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite str...MnxCe1- xO2(x: 0.3–0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde(HCHO). At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of Ce O2 to form a solid solution. The catalytic activity was best at x = 0.5, at which the temperature of 100% removal rate is the lowest(270°C). The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5 wt.% Cu Oxinto Mn0.5Ce0.5O2. With ozone catalytic oxidation, HCHO(61 ppm) in gas stream was completely oxidized by adding 506 ppm O3 over Mn0.5Ce0.5O2 catalyst with a GHSV(gas hourly space velocity) of 10,000 hr-1at 25°C. The effect of the molar ratio of O3 to HCHO was also investigated. As O3/HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O3/HCHO ratio of 8, the mineralization efficiency of HCHO to CO2 was 86.1%. At 25°C, the p-type oxide semiconductor(Mn0.5Ce0.5O2) exhibited an excellent ozone decomposition efficiency of 99.2%,which significantly exceeded that of n-type oxide semiconductors such as Ti O2, which had a low ozone decomposition efficiency(9.81%). At a GHSV of 10,000 hr-1, [O3]/[HCHO] = 3 and temperature of 25°C, a high HCHO removal efficiency(≥ 81.2%) was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal.展开更多
Treatment of drilling wastewater from a sulfonated drilling mud system in the Shengli Oilfield, East China, was studied. The wastewater was deeply treated by a chemical coagulationcentrifugal separation-ozone catalyti...Treatment of drilling wastewater from a sulfonated drilling mud system in the Shengli Oilfield, East China, was studied. The wastewater was deeply treated by a chemical coagulationcentrifugal separation-ozone catalytic oxidation combined process. The factors (i.e. pH value, chemical dosage, reaction time, etc.) influencing the treatment effect were investigated, and pH = 7 was determined as optimal for the coagulation; polymeric aluminum chloride (PAC) was selected as the optimal coagulant with a dosage of 18 g/L; cationic polyacrylamide (CPAM) with molecular weight of 8 million was selected as the optimal coagulant aid with an optimum dosage of 8 mg/L; and the optimal condition of catalytic ozonation was found to be a pH of 12 and an oxidation time of 40 min. The results showed that the combined treatment process was effective. The oil content and suspended solids content of the effluent reached the first class discharge standard according to China's standard GB 8978-1996 (Integrated Wastewater Discharge Standard) and the chemical oxygen demand (COD) decreased to 195 mg/L from 2.34×10^4 mg/L after coagulation process and ozone oxidation at pH = 12 for 40 min.展开更多
Novel Mn–Fe–Mg-and Mn–Fe–Ce-loaded alumina(Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3) were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters(PRW-ROC). Hi...Novel Mn–Fe–Mg-and Mn–Fe–Ce-loaded alumina(Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3) were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters(PRW-ROC). Highly dispersed 100–300-nm deposits of composite multivalent metal oxides of Mn(Mn^2+), Mn^3+,and Mn^4+, Fe(Fe^2+)and Fe^3+ and Mg(Mg^2+), or Ce(Ce^4+) were achieved on Al2O3 supports. The developed Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 exhibited higher catalytic activity during the ozonation of PRW-ROC than Mn–Fe/Al2O3, Mn/Al2O-3, Fe/Al2O3, and Al2O3. Chemical oxygen demand removal by Mn–Fe–Mg/Al2O3-or Mn–Fe–Ce/Al2O3-catalyzed ozonation increased by 23.9% and23.2%, respectively, in comparison with single ozonation.Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 notably promoted áOH generation and áOH-mediated oxidation. This study demonstrated the potential use of composite metal oxide-loaded Al2O3 in advanced treatment of bio-recalcitrant wastewaters.展开更多
With the continuous development of nanomaterials in recent years,the application of nanocatalysts in catalytic ozone oxidation has attracted more and more researchers’attention due to their excellent catalytic proper...With the continuous development of nanomaterials in recent years,the application of nanocatalysts in catalytic ozone oxidation has attracted more and more researchers’attention due to their excellent catalytic properties.In this review,we systematically summarized the current research status of nanocatalysts mainly involving material categories,mechanisms and catalytic efficiency.Based on summary and analysis,we found most of the reported nanocatalysts were in the stage of laboratory research,which was caused by the nanocatalysts defects such as easy aggregation,difficult separation,and easy leakage.These defects might result in severe resource waste,economic loss and potentially adverse effects imposed on the ecosystem and human health.Aiming at solving these defects,we further analyzed the reasons and the existing reports,and revealed that coupling nano-catalyst and membrane,supported nanocatalysts and magnetic nanocatalysts had promising potential in solving these problems and promoting the actual application of nanocatalysts in wastewater treatment.Furthermore,the advantages,shortages and our perspectives of these methods are summarized and discussed.展开更多
As one of the most promising and practical advanced oxidation processes(AOPs),the catalytic ozonation is triggered by the active components of catalyst,which are usually derived from metals or metal oxides.To avoid th...As one of the most promising and practical advanced oxidation processes(AOPs),the catalytic ozonation is triggered by the active components of catalyst,which are usually derived from metals or metal oxides.To avoid the metal pollution from catalyst,here the amorphous boron(A-boron)is used as a metalfree catalyst for catalytic ozonation to produce free radicals for effective degradation of atrazine(ATZ),the world-widely used herbicide and also a widespread pollutant in environment.A-boron exhibits an outstanding performance for catalytic ozonation to remove ATZ from water.As A-boron is introduced into ozonation,the degradation efficiency in 10 min is promoted to 97.1%,much higher than that of 15.1%under ozonation.The mechanism is that the B-B bonds and internal suboxide B in A-boron serve as the main active sites to donate electrons to accelerate ozone decomposition to produce reactive oxygen species(ROS),including·O_(2)^(-)and^(1)O_(2),and further enhance ATZ degradation via ROS reactions.Moreover,the A-boron is still highly active with a degradation efficiency of ATZ over 95%in 10 min even after four successive cycles.This work shows A-boron could be an alternative for the active components of metal or metal oxide in catalytic ozonation.展开更多
The improvement of catalysts’stability under harsh reaction conditions is vital for their practical applica-bility.Herein,iron carbide(Fe_(3)C)nanoparticles were encapsulated in graphitic carbon in situ and a carbon ...The improvement of catalysts’stability under harsh reaction conditions is vital for their practical applica-bility.Herein,iron carbide(Fe_(3)C)nanoparticles were encapsulated in graphitic carbon in situ and a carbon ball served as the carrier.The synthesized Fe_(3)C@C/C was first utilized to treat an m-cresol wastewater containing Si via catalytic ozonation.Compared with the commercial Fe/Al_(2)O_(3)catalyst,the resistance to Si of the Fe_(3)C@C/C was improved 22.68 times,while the TOC removal rate increased by a factor of 2.9,and it remained stable during 10 cycles and 12000 min of continuous reaction,which further demon-strated its potential for diverse applications.The catalyst exhibits improved resistance to Si because of the dual protection from the carbon-encapsulated structure and carbon carrier.Density functional theory calculations show that the encapsulation of Fe_(3)C using carbon significantly increases the resistance to adsorption of Si on its active sites.In addition,the activation of O_(3)is unimpeded on the Fe_(3)C adsorption sites by the protection from C,thus the generation of reactive oxygen species(ROS)by ozone is largely promoted.The mechanism associated with the resistance of the Fe_(3)C@C/C catalyst to Si and its elevated activity are also elucidated.展开更多
Catalytic ozonation is regarded as a promising technology in the advanced treatment of refractory organic wastewater.Packed-bed reactors are widely used in practical applications due to simple structures,installation ...Catalytic ozonation is regarded as a promising technology in the advanced treatment of refractory organic wastewater.Packed-bed reactors are widely used in practical applications due to simple structures,installation and operation.However,mass transfer of packed-bed reactors is relatively restrained and amplified deviations usually occurred in scale-up application.Herein,a multi-scale packed-bed model of catalytic ozonation was established to guide pilot tests.First,a laboratory-scale test was conducted to obtain kinetic parameters needed for modeling.Then,a multi-scale packed-bed model was developed to research the effects of water distribution structure,catalyst particle size,and hydraulic retention time(HRT)on catalytic ozonation.It was found that the performance of packed bed reactor was increased with evenly distributed water inlet,HRT of 60 min,and catalyst diameter of about 3-7 mm.Last,an optimized reactor was manufactured and a pilot-scale test was conducted to treat kitchen wastewater using catalytic ozonation process.In the pilot-scale test with an ozone dosage of 50 mg/L and HRT of 60 min,the packed-bed reactor filled with catalysts I was able to reduce chemical oxygen demand(COD)from 117 to 59 mg/L.The performance of the catalytic ozonation process in the packed-bed reactor for the advanced treatment of actual kitchen wastewater was investigated via both multi-scale simulation and pilot-scale tests in this study,which provided a practical method for optimizing the reactors of treating refractory organic wastewater.展开更多
Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe(NO3)3.9H2O and Co(NO3)2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophen...Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe(NO3)3.9H2O and Co(NO3)2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophenoxy)propionic acid (2,4-DP), nitrobenzene and oxalic acid. The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant, and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism. The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance. In the catalytic ozonation of 2,4-DP, the apparent reaction rate constants (k) were determined to be 1.456 × 10^-2 min-1 for ozonation alone and 4.740 × 10^-2 min^-1 for O3/Fe3O4-CoO/Al2O3. And O3/Fe3O4-CoO/Al2O3 had a larger Rot (6.614 × 10^-9) calculated by the relative method than O3 did (1.800 x 10-9), showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical. Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid. The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.展开更多
The catalytic ozonation treatment of secondary biochemical effluent for papermaking wastewater by Ag-doped nickel ferrite was investigated.Ag-doped catalysts prepared by sol-gel method were characterized,illustrating ...The catalytic ozonation treatment of secondary biochemical effluent for papermaking wastewater by Ag-doped nickel ferrite was investigated.Ag-doped catalysts prepared by sol-gel method were characterized,illustrating that Ag entirely entered the crystalline of Ni Fe2O4 and changed the surface properties.The addition of catalyst enhanced the removal efficiency of chemical oxygen demand and total organic carbon.The results of gas chromatography-mass spectrometer,ultraviolet light absorbance at 254 nm and threedimensional fluorescence excitation-emission matrix suggested that aromatic compounds were efficiently degraded and toxic substances,such as dibutyl phthalate.In addition,the radical scavenging experiments confirmed the hydroxyl radicals acted as the main reactive oxygen species and the surface properties of catalysts played an important role in the reaction.Overall,this work validated potential applications of Ag-doped Ni Fe2O4 catalyzed ozonation process of biologically recalcitrant wastewater.展开更多
The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral res...The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral resources. The effective use of these secondary resources is becoming an important and urgent problem for all environmental protection staff. Manganese-catalyzed ozonation for the pre-oxidation of cyanided tailings was studied and the effects of Mn2+dosage, initial sulfuric acid concentration, ozone volume flow, temperature and agitation speed on pretreatment were examined. The optimum reaction conditions were observed to be: ore pulp density 2.5%, agitation speed 700 r/min,temperature 60°C, Mn2+dosage 40 g/L, ozone volume flow 80 L/hr, initial sulfuric acid concentration 1 mol/L, and reaction time 6 hr. Under these conditions, the leaching rate of Fe and weight loss could reach 94.85% and 48.89% respectively. The leaching process of cyanided tailings by Mn2+/O3 was analyzed, and it was found that the leaching of pyrite depends on synergetic oxidation by high-valent manganese and O3, in which the former played an important part.展开更多
Fe304 was supported on mesoporous A12O3 or SiO2 (50 wt.%) using an incipient wetness impregnation method, and Fe304/A12O3 exhibited higher catalytic efficiency for the degradation of 2,4-dichlorophenoxyace- tic acid...Fe304 was supported on mesoporous A12O3 or SiO2 (50 wt.%) using an incipient wetness impregnation method, and Fe304/A12O3 exhibited higher catalytic efficiency for the degradation of 2,4-dichlorophenoxyace- tic acid andpara-chlorobenzoic acid aqueous solution with ozone. The effect and morphology of supported Fe304 on catalytic ozonation performance were investigated based on the characterization results of X-ray diffraction, X-ray photoelectron spectroscopy, BET analysis and Fourier transform infrared spectroscopy. The results indicated that the physical and chemical properties of the catalyst supports especially their Lewis acid sites had a significant influence on the catalytic activity. In comparison with SiO2, more Lewis acid sites existed on the surface of A12O3, resulting in higher catalytic ozonation activity. During the reaction process, no significant Fe ions release was observed. Moreover, Fe304/A12O3 exhibited stable structure and activity after successive cyclic experiments. The results indicated that the catalyst is a promising ozonation catalyst with magnetic separation in drinking water treatment.展开更多
文摘Catalytic technologies have been paid increasing attention in refractory pollutants abatement due to its practical and potential values in water purification. As effective and efficient approaches for water purification, Fenton's reagent, ozonation, electrochemical and photocatalytic methods have been widely studied and applied in different aspects and have been reviewed by several articles. In recent years, some novel catalytic processes based on above processes have been developed for enhancing the efficiency of removing the organics from water. This review emphasized on the recent development of heterogeneous catalytic ozonation, electrocatalysis in respect of novel electrodes and electro-Fenton method, photoelectrocatalysis process and photoelectron-Fenton in water purification. It was also an attempt to propose general ideas about mechanism and principle enhancing the catalytic efficiency for the degradation and the mineralization of organics in water.
基金The National Natural Science Foundation of China(No.50378028)
文摘The degradation of nitrobenzene by ceramic-honeycomb catalyzed ozonation was investigated. The results showed that the presence of ceramic honeycombs significantly increased the oxidation rate of nitrobenzene by ozone compared to the case of ozone oxidation alone. In this paper, the effects of various factors on the catalytic oxidation were investigated, such as the amount of catalysts, the ozone dosage, the temperature, the pH value and the presence of tert-butanol. With the addition of tert-butanol the removal of nitrobenzene decreased sharply, which appeared to support that, the degradation of nitrobenzene by ozonation followed a radical type mechanism. The EPR experiments verified that higher nitrobenzene removal rate was attributed to more OH radicals generated in the catalyzed ozonation than ozonation alone.
基金Supported by the National Natural Science Foundation of China(No20476019)
文摘Different series of transition metal catalysts supported on Al2O3 were prepared by the impregnation method. The catalytic activity was measured in a batch reactor with ozone as the oxidizing reagent. The experimental results indicate that Cu/Al2O3 has a very effective catalytic activity during the ozonation of organic pollutants in water. The optimum conditions for preparing Cu/Al2O3 were systematically investigated with the orthogonal testing method. Furthermore, the results also show that the surface properties of catalyst are not compulsory for effective oxidation.
基金The project was supported by the National Natural Science Foundation of China(No.29877024)
文摘This paper describes the potential of heterogeneous catalytic ozonization of sulfo-salicylic acid (SSal). It was found that catalytic ozonization in the presence of Mn-Zr-O (a modified manganese dioxide supported on silica gel) had significantly enhanced the removal rate (72%) of total organic carbon (TOC) compared with that of ozonization alone (19%). The efficient removal rate of TOC was probably due to increasing the adsorption ability of catalyst and accelerating decomposition of ozone to produce more powerful oxidants than ozone. .
基金the National Key R&D Program of the Ministry of Science and Technology,China(Grant No.2018YFC0705304)and the Key Scientific and Technological Support Projects,Tianjin City,China(Grant No.19YFZCSF01090).
文摘Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)was pretreated with 10%H_(2)SO_(4)by single factor optimization to increase specific surface area and pore volume obviously.The catalytic ozonation performance of ACF loaded with Au,Ag,Pt and Pd noble metals on ethyl acetate was investigated and Pd/ACF was selected as the optimal catalyst which had certain stability.Pd is uniformly distributed on the surface of ACF,and Palladium mainly exists in the form of Pd0 with a amount of Pd+2.The specific surface area of the catalysts gradually decreases as the loading increases.The activation energy of ethyl acetate calculated by Arrhenius equation is 113 kJ mol 1.With 1%Pd loading and the concentration ratio of ozone to ethyl acetate is 3:1,catalytic ozonation performance is maximized and the conversion rate of ethyl acetate reached to 60%in 3050℃Cat 15,00030,000 h^1.
基金Sponsored by the State Key Lab of Urban Water Resource and Environment (Grant No.ESK200801)
文摘CuO particles were attempted to fill in the channel of multi-walled carbon nanotubes (MWCNTs) as novel catalytic materials CuO@MWCNTs used for ozonation of humic acids (HA) in aqueous solution.Catalyst samples were characterized by transmission electron microscopy (TEM),X-ray diffraction (XRD),thermogravimetric analysis (TG) and X-ray photoelectron spectroscopy (XPS).The removal efficiency of HA was promoted in the presence of CuO@MWCNTs compared with that of Al2O3-supported CuO catalyst (CuO/Al2O3) and CuO-coating MWCNTs catalyst (CuO/MWCNTs).The strong synergetic effect in the confinement environment on CuO nanoparticles can attribute to the locally higher pressure due to the lower potential energy of reactants in the channels.Strong interaction happened between the catalyst and reactants,which promoted the decomposition of ozone and the generation of OH.The results of experimental and theoretical investigation confirmed that CuO@MWCNTs promotes the initiation and generation of OH,hence accelerating the degradation of organic pollutants.
基金supported by the National Natural Science Foundation of China (Nos. 52192684 and 52270136)the National Key Research and Development Project (No. 2020YFC1908704)China Three Gorges Corporation (No. 202003166)。
文摘To improve the sludge conditioning efficiency without increasing the ozone dose,an in-situ sludge reduction process based on Mn^(2+)-catalytic ozonation conditioning was proposed.Using ozone conditioning alone as a control,a lab-scale sequencing batch reactor coupled with ozonated sludge recycle was evaluated for its operating performance at an ozone dose of 75 mg O_(3)/g VSS and 1.5 mmol/L Mn^(2+)addition.The results showed a 39.4%reduction in MLSS and an observed sludge yield of 0.236 kg MLSS/kg COD for the O_(3)+Mn^(2+)group compared to the O_(3)group (15.3%and 0.292 kg MLSS/kg COD),accompanied by better COD,NH_(4)^(+)-N,TN and TP removal,improved effluent SS and limited impact on excess sludge properties.Subsequently,activity tests,BIOLOG ECO microplates and 16S rRNA sequencing were applied to elucidate the changing mechanisms of Mn^(2+)-catalytic ozonation related to microbial action:(1) Dehydrogenase activity reached a higher peak.(2) Microbial utilization of total carbon sources had an elevated effect,up to approximately 18%,and metabolic levels of six carbon sources were also increased,especially for sugars and amino acids most pronounced.(3) The abundance of Defluviicoccus under the phylum Proteobacteria was enhanced to 12.0%and dominated in the sludge,they had strong hydrolytic activity and metabolic capacity.Denitrifying bacteria of the genus Ferruginibacter also showed an abundance of 7.6%,they contributed to the solubilization and reduction of sludge biomass.These results could guide researchers to further reduce ozonation conditioning costs,improve sludge management and provide theoretical support.
基金supported by the National Natural Science Foundation of China (No.51878394)the Introduction and Cultivation Plan for Young Innovative Talents of Colleges and Universities by the Education Department of Shandong Province。
文摘In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.
基金The National Natural Science Foundation of China (No. 50378028)
文摘Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance (EPR) experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.
文摘MnxCe1- xO2(x: 0.3–0.9) prepared by Pechini method was used as a catalyst for the thermal catalytic oxidation of formaldehyde(HCHO). At x = 0.3 and 0.5, most of the manganese was incorporated in the fluorite structure of Ce O2 to form a solid solution. The catalytic activity was best at x = 0.5, at which the temperature of 100% removal rate is the lowest(270°C). The temperature for 100% removal of HCHO oxidation is reduced by approximately 40°C by loading 5 wt.% Cu Oxinto Mn0.5Ce0.5O2. With ozone catalytic oxidation, HCHO(61 ppm) in gas stream was completely oxidized by adding 506 ppm O3 over Mn0.5Ce0.5O2 catalyst with a GHSV(gas hourly space velocity) of 10,000 hr-1at 25°C. The effect of the molar ratio of O3 to HCHO was also investigated. As O3/HCHO ratio was increased from 3 to 8, the removal efficiency of HCHO was increased from 83.3% to 100%. With O3/HCHO ratio of 8, the mineralization efficiency of HCHO to CO2 was 86.1%. At 25°C, the p-type oxide semiconductor(Mn0.5Ce0.5O2) exhibited an excellent ozone decomposition efficiency of 99.2%,which significantly exceeded that of n-type oxide semiconductors such as Ti O2, which had a low ozone decomposition efficiency(9.81%). At a GHSV of 10,000 hr-1, [O3]/[HCHO] = 3 and temperature of 25°C, a high HCHO removal efficiency(≥ 81.2%) was maintained throughout the durability test of 80 hr, indicating the long-term stability of the catalyst for HCHO removal.
基金National High Technology Research and Development Program of China(No. 2013AA064301)National Natural Science Foundation of China (No. 51274210)
文摘Treatment of drilling wastewater from a sulfonated drilling mud system in the Shengli Oilfield, East China, was studied. The wastewater was deeply treated by a chemical coagulationcentrifugal separation-ozone catalytic oxidation combined process. The factors (i.e. pH value, chemical dosage, reaction time, etc.) influencing the treatment effect were investigated, and pH = 7 was determined as optimal for the coagulation; polymeric aluminum chloride (PAC) was selected as the optimal coagulant with a dosage of 18 g/L; cationic polyacrylamide (CPAM) with molecular weight of 8 million was selected as the optimal coagulant aid with an optimum dosage of 8 mg/L; and the optimal condition of catalytic ozonation was found to be a pH of 12 and an oxidation time of 40 min. The results showed that the combined treatment process was effective. The oil content and suspended solids content of the effluent reached the first class discharge standard according to China's standard GB 8978-1996 (Integrated Wastewater Discharge Standard) and the chemical oxygen demand (COD) decreased to 195 mg/L from 2.34×10^4 mg/L after coagulation process and ozone oxidation at pH = 12 for 40 min.
基金supported in part by the National Science and Technology Major Project of China (No. 2016ZX05040-003)
文摘Novel Mn–Fe–Mg-and Mn–Fe–Ce-loaded alumina(Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3) were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters(PRW-ROC). Highly dispersed 100–300-nm deposits of composite multivalent metal oxides of Mn(Mn^2+), Mn^3+,and Mn^4+, Fe(Fe^2+)and Fe^3+ and Mg(Mg^2+), or Ce(Ce^4+) were achieved on Al2O3 supports. The developed Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 exhibited higher catalytic activity during the ozonation of PRW-ROC than Mn–Fe/Al2O3, Mn/Al2O-3, Fe/Al2O3, and Al2O3. Chemical oxygen demand removal by Mn–Fe–Mg/Al2O3-or Mn–Fe–Ce/Al2O3-catalyzed ozonation increased by 23.9% and23.2%, respectively, in comparison with single ozonation.Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 notably promoted áOH generation and áOH-mediated oxidation. This study demonstrated the potential use of composite metal oxide-loaded Al2O3 in advanced treatment of bio-recalcitrant wastewaters.
基金financially supported by the China special Science and Technology project on treatment and control of water pollution(No.2017ZX07402002)
文摘With the continuous development of nanomaterials in recent years,the application of nanocatalysts in catalytic ozone oxidation has attracted more and more researchers’attention due to their excellent catalytic properties.In this review,we systematically summarized the current research status of nanocatalysts mainly involving material categories,mechanisms and catalytic efficiency.Based on summary and analysis,we found most of the reported nanocatalysts were in the stage of laboratory research,which was caused by the nanocatalysts defects such as easy aggregation,difficult separation,and easy leakage.These defects might result in severe resource waste,economic loss and potentially adverse effects imposed on the ecosystem and human health.Aiming at solving these defects,we further analyzed the reasons and the existing reports,and revealed that coupling nano-catalyst and membrane,supported nanocatalysts and magnetic nanocatalysts had promising potential in solving these problems and promoting the actual application of nanocatalysts in wastewater treatment.Furthermore,the advantages,shortages and our perspectives of these methods are summarized and discussed.
基金Financial support is provided by the Key Research and Development Program of Zhejiang Province(No.2021C03179)the National Key Research and Development Program of China(No.2019YFC0408802)。
文摘As one of the most promising and practical advanced oxidation processes(AOPs),the catalytic ozonation is triggered by the active components of catalyst,which are usually derived from metals or metal oxides.To avoid the metal pollution from catalyst,here the amorphous boron(A-boron)is used as a metalfree catalyst for catalytic ozonation to produce free radicals for effective degradation of atrazine(ATZ),the world-widely used herbicide and also a widespread pollutant in environment.A-boron exhibits an outstanding performance for catalytic ozonation to remove ATZ from water.As A-boron is introduced into ozonation,the degradation efficiency in 10 min is promoted to 97.1%,much higher than that of 15.1%under ozonation.The mechanism is that the B-B bonds and internal suboxide B in A-boron serve as the main active sites to donate electrons to accelerate ozone decomposition to produce reactive oxygen species(ROS),including·O_(2)^(-)and^(1)O_(2),and further enhance ATZ degradation via ROS reactions.Moreover,the A-boron is still highly active with a degradation efficiency of ATZ over 95%in 10 min even after four successive cycles.This work shows A-boron could be an alternative for the active components of metal or metal oxide in catalytic ozonation.
基金This work was financially supported by the Youth Innovation Promotion Association CAS(No.2020190)the National Natural Science Foundation of China(No.52100072)+1 种基金the Scientific Research Common Program of Beijing Municipal,Commission of Education(No.KM202010017006)the Beijing Natural Science Foundation(No.8214056).
文摘The improvement of catalysts’stability under harsh reaction conditions is vital for their practical applica-bility.Herein,iron carbide(Fe_(3)C)nanoparticles were encapsulated in graphitic carbon in situ and a carbon ball served as the carrier.The synthesized Fe_(3)C@C/C was first utilized to treat an m-cresol wastewater containing Si via catalytic ozonation.Compared with the commercial Fe/Al_(2)O_(3)catalyst,the resistance to Si of the Fe_(3)C@C/C was improved 22.68 times,while the TOC removal rate increased by a factor of 2.9,and it remained stable during 10 cycles and 12000 min of continuous reaction,which further demon-strated its potential for diverse applications.The catalyst exhibits improved resistance to Si because of the dual protection from the carbon-encapsulated structure and carbon carrier.Density functional theory calculations show that the encapsulation of Fe_(3)C using carbon significantly increases the resistance to adsorption of Si on its active sites.In addition,the activation of O_(3)is unimpeded on the Fe_(3)C adsorption sites by the protection from C,thus the generation of reactive oxygen species(ROS)by ozone is largely promoted.The mechanism associated with the resistance of the Fe_(3)C@C/C catalyst to Si and its elevated activity are also elucidated.
基金supported by the“Explorer 100”cluster system of Tsinghua HPC Platform.
文摘Catalytic ozonation is regarded as a promising technology in the advanced treatment of refractory organic wastewater.Packed-bed reactors are widely used in practical applications due to simple structures,installation and operation.However,mass transfer of packed-bed reactors is relatively restrained and amplified deviations usually occurred in scale-up application.Herein,a multi-scale packed-bed model of catalytic ozonation was established to guide pilot tests.First,a laboratory-scale test was conducted to obtain kinetic parameters needed for modeling.Then,a multi-scale packed-bed model was developed to research the effects of water distribution structure,catalyst particle size,and hydraulic retention time(HRT)on catalytic ozonation.It was found that the performance of packed bed reactor was increased with evenly distributed water inlet,HRT of 60 min,and catalyst diameter of about 3-7 mm.Last,an optimized reactor was manufactured and a pilot-scale test was conducted to treat kitchen wastewater using catalytic ozonation process.In the pilot-scale test with an ozone dosage of 50 mg/L and HRT of 60 min,the packed-bed reactor filled with catalysts I was able to reduce chemical oxygen demand(COD)from 117 to 59 mg/L.The performance of the catalytic ozonation process in the packed-bed reactor for the advanced treatment of actual kitchen wastewater was investigated via both multi-scale simulation and pilot-scale tests in this study,which provided a practical method for optimizing the reactors of treating refractory organic wastewater.
基金supported by the National Natural Science Foundation of China(No.50578146,20876151)the National Science Foundation of Zhejiang Province,China(No.Y5080178)
文摘Fe3O4-CoO/Al2O3 catalyst was prepared by incipient wetness impregnation using Fe(NO3)3.9H2O and Co(NO3)2.6H2O as the precursors, and its catalytic performance was investigated in ozonation of 2-(2,4-dichlorophenoxy)propionic acid (2,4-DP), nitrobenzene and oxalic acid. The experimental results indicated that Fe3O4-CoO/Al2O3 catalyst enabled an interesting improvement of ozonation efficiency during the degradation of each organic pollutant, and the Fe3O4-CoO/Al2O3 catalytic ozonation system followed a radical-type mechanism. The kinetics of ozonation alone and Fe3O4-CoO/Al2O3 catalytic ozonation of three organic pollutants in aqueous solution were discussed under the mere consideration of direct ozone reaction and OH radical reaction to well investigate its performance. In the catalytic ozonation of 2,4-DP, the apparent reaction rate constants (k) were determined to be 1.456 × 10^-2 min-1 for ozonation alone and 4.740 × 10^-2 min^-1 for O3/Fe3O4-CoO/Al2O3. And O3/Fe3O4-CoO/Al2O3 had a larger Rot (6.614 × 10^-9) calculated by the relative method than O3 did (1.800 x 10-9), showing O3/Fe3O4-CoO/Al2O3 generated more hydroxyl radical. Similar results were also obtained in the catalytic ozonation of nitrobenzene and oxalic acid. The above results demonstrated that the catalytic performance of Fe3O4-CoO/Al2O3 in ozonation of studied organic substance was universal to a certain degree.
基金supported by National Key R&D Program of China(No.2018YFC0406300)the operation for central university of Hohai University(No.2013/B18020148)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘The catalytic ozonation treatment of secondary biochemical effluent for papermaking wastewater by Ag-doped nickel ferrite was investigated.Ag-doped catalysts prepared by sol-gel method were characterized,illustrating that Ag entirely entered the crystalline of Ni Fe2O4 and changed the surface properties.The addition of catalyst enhanced the removal efficiency of chemical oxygen demand and total organic carbon.The results of gas chromatography-mass spectrometer,ultraviolet light absorbance at 254 nm and threedimensional fluorescence excitation-emission matrix suggested that aromatic compounds were efficiently degraded and toxic substances,such as dibutyl phthalate.In addition,the radical scavenging experiments confirmed the hydroxyl radicals acted as the main reactive oxygen species and the surface properties of catalysts played an important role in the reaction.Overall,this work validated potential applications of Ag-doped Ni Fe2O4 catalyzed ozonation process of biologically recalcitrant wastewater.
基金supported by the Innovation Foundation of Donghua University for Doctoral Candidates (No. BC201132)the Shanghai Leading Academic Discipline Project (No. B604)
文摘The increasing amount of cyanided tailings produced as a by-product has gained significant attention in recent years because of the rapid development of the gold industry and extensive exploitation of gold mineral resources. The effective use of these secondary resources is becoming an important and urgent problem for all environmental protection staff. Manganese-catalyzed ozonation for the pre-oxidation of cyanided tailings was studied and the effects of Mn2+dosage, initial sulfuric acid concentration, ozone volume flow, temperature and agitation speed on pretreatment were examined. The optimum reaction conditions were observed to be: ore pulp density 2.5%, agitation speed 700 r/min,temperature 60°C, Mn2+dosage 40 g/L, ozone volume flow 80 L/hr, initial sulfuric acid concentration 1 mol/L, and reaction time 6 hr. Under these conditions, the leaching rate of Fe and weight loss could reach 94.85% and 48.89% respectively. The leaching process of cyanided tailings by Mn2+/O3 was analyzed, and it was found that the leaching of pyrite depends on synergetic oxidation by high-valent manganese and O3, in which the former played an important part.
文摘Fe304 was supported on mesoporous A12O3 or SiO2 (50 wt.%) using an incipient wetness impregnation method, and Fe304/A12O3 exhibited higher catalytic efficiency for the degradation of 2,4-dichlorophenoxyace- tic acid andpara-chlorobenzoic acid aqueous solution with ozone. The effect and morphology of supported Fe304 on catalytic ozonation performance were investigated based on the characterization results of X-ray diffraction, X-ray photoelectron spectroscopy, BET analysis and Fourier transform infrared spectroscopy. The results indicated that the physical and chemical properties of the catalyst supports especially their Lewis acid sites had a significant influence on the catalytic activity. In comparison with SiO2, more Lewis acid sites existed on the surface of A12O3, resulting in higher catalytic ozonation activity. During the reaction process, no significant Fe ions release was observed. Moreover, Fe304/A12O3 exhibited stable structure and activity after successive cyclic experiments. The results indicated that the catalyst is a promising ozonation catalyst with magnetic separation in drinking water treatment.