The efficient mineralization of phenol and its derivatives in wastewater remains a great challenge.In this study,the bimetallic CuCeO_(2)-BTC was screened from a series of MOFs-derived MCeO_(2)-BTC(M=La,Cu,Co,Fe,and M...The efficient mineralization of phenol and its derivatives in wastewater remains a great challenge.In this study,the bimetallic CuCeO_(2)-BTC was screened from a series of MOFs-derived MCeO_(2)-BTC(M=La,Cu,Co,Fe,and Mn)catalysts,and the influence of the Cu/Ce ratio on phenol removal by catalytic ozonation was carefully examined.The results indicate that Cu_(2)Ce_(1)O_(y)-BTC was the best among the Cu_(x)Ce_(1)O_(y)-BTC(x=0,1,2,and 3)catalysts,with a phenol mineralization efficiency reaching close to 100%within 200 min,approximately 30.1%higher than CeO_(2)-BTC/O_(3)and 70.3%higher than O_(3)alone.The order of mineralization efficiency of phenol was Cu_(2)Ce_(1)O_(y)-BTC>Cu_(3)Ce_(1)O_(y)-BTC>Cu_(1)Ce_(1)O_(y)-BTC>CeO_(2)-BTC.CeO_(2)-BTC exhibited a broccoli-like morphology,and Cu_(x)Ce_(1)O_(y)-BTC(x=1,2,and 3)exhibited an urchin-like morphology.Compared with Cu_(x)Ce_(1)O_(y)-BTC(x=0,1,and 3),Cu_(2)Ce_(1)O_(y)-BTC exhibited a larger specific surface area and pore volume.This characteristic contributed to the availability of more active sites for phenol degradation.The redox ability was greatly enhanced as well.Besides,the surface of Cu_(2)Ce_(1)O_(y)-BTC exhibited a higher concentration of Ce^(3+)species and hydroxyl groups,which facilitated the dissociation of ozone and the generation of active radicals.Based on the results of radical quenching experiments and the intermediates detected by LC-MS,a potential mechanism for phenol degradation in the Cu_(2)Ce_(1)O_(y)-BTC/O_(3)system was postulated.This study offers novel perspectives on the advancement of MOFs-derived catalysts for achieving the complete mineralization of phenol in wastewater through catalytic ozonation.展开更多
In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidati...In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidation methods such as ozonation system are used to manage MnS_(2)O_(6)in the leaching solution,replacing conventional methods.To ascertain the conversion rate and kinetics of MnS_(2)O_(6)during the ozonation process,we explored the factors influencing its removal rate,including ozone dosage,manganese dithionate concentration,sulfuric acid concentration,and reaction temperature.Batch experiments were conducted to determine the reaction rate constant of ozone(k)and activation energy(Ea)obtained from intermittent experimental data fitting,revealing a least-squares exponential conversion relationship between k and the MnS_(2)O_(6)removal amount,wherein an increase in the aforementioned factors led to an enhanced MnS_(2)O_(6)conversion rate,exceeding 99.3%.The formation mechanism of the ozone products proposed during the experiment was summarized and proposed as follows:1)Mn^(2+)was directly oxidized to MnO_(2),and 2)SO_(4)2−was obtained by the catalytic oxidation of S_(2)O_(6)^(2−)with HO•from O3 decomposition.According to the kinetics analysis,the pre-exponential factor and total activation energy of the ozonation kinetics equation were 1.0×10^(23) s^(−1) and 177.28 kJ/mol,respectively.Overall,the present study demonstrates that O_(3) as an oxidizing agent can effectively facilitate MnS_(2)O_(6)disproportionation while preventing the release of the secondary pollutant,SO_(2)gas.展开更多
This study aims to identify the highly non-specific toxic by-products during ozonation of three cresols in wastewater.In ozonated effluents,biotoxicity increased along with increasing reaction time,followed by a gradu...This study aims to identify the highly non-specific toxic by-products during ozonation of three cresols in wastewater.In ozonated effluents,biotoxicity increased along with increasing reaction time,followed by a gradual decrease.The peak biotoxicity for ozonated o-cresol(o-C),m-cresol(m-C),and p-cresol(p-C)was estimated to be 17.4,14.8 and 5.5 times higher than that of untreated wastewater,respectively.A redox-directed approach with high-resolution mass spectrometry detection and toxicity prediction revealed that monomeric para-benzoquinones(p-BQs),hydroxylated p-BQs,and dimeric p-BQs in ozonated cresols were the primary contributors to the increased toxicity.Calculations based on density functional theory indicated formation pathways of p-BQs byproducts,e.g.,the formation of 2-methyl-p-benzoquinone was likely induced by ozone molecules rather than hydroxyl radicals in ozonated o-C and m-C,and the formation of p-BQs during ozonation of p-C was attributed to the oxidation of methyl group to carboxyl group and subsequent decarboxylation initiated by hydroxyl radicals.Electron paramagnetic resonance and spin density calculation showed that the presence of carbon-centered cresoxyl radicals was responsible for dimeric p-BQs formation.Collectively,these results underscore significant contribution of non-halogenated p-BQs to non-specific toxicity increase in ozonated effluents.展开更多
Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer d...Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer dynamics.Herein,we employed in-situ DRIFTS and Raman spectroscopy to elucidate the distinct adsorption and activation behaviors of ozone(O_(3))on the{001}and{110}crystal facets of Bi_(2)O_(2)CO_(3)(BOC)nanosheets.BOC-{001}demonstrates superior photocatalytic ozonation performance,with 85%phenol mineralization and excellent durability,significantly outperforming the 53%mineralization rate of BOC-{110}.This enhanced activity is attributed to non-dissociative ozone adsorption and favorable adsorption energy over{001}facet,which facilitate the one-electron O_(3) reduction pathway.Furthermore,crystal facet engineering strengthens the built-in electric field,promoting exciton dissociation and the generation of localized charge carriers.The synergistic effects of optimized electron availability and ozone adsorption significantly boost the production of reactive oxygen species.These findings provide a deeper understanding of the critical roles of O_(3) adsorption and electron transfer in radical generation,which could provide some guidance for the strategic development of highly effective photocatalytic ozonation catalysts.展开更多
Nowadays,it is still a challenge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle the long-living indoor air pollution.Herein,δ-MnO_(2)is successfully synthesized by a f...Nowadays,it is still a challenge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle the long-living indoor air pollution.Herein,δ-MnO_(2)is successfully synthesized by a facile ozonation strategy,where Mn^(2+)is oxidized by ozone(O_(3))bubble in an alkaline solution.It presents one of the best catalytic properties with a low 100%conversion temperature of 85℃for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr).As a comparison,more than 6 times far longer oxidation time is needed if O3 is replaced by O_(2).Characterizations show that ozonation process generates a different intermediate of tetragonalβ-HMnO_(2),which would favor the quick transformation into the final productδ-MnO_(2),as compared with the relatively more thermodynamically stable monoclinicγ-HMnO_(2)in the O_(2)process.Finally,HCHO is found to be decomposed into CO_(2)via formate,dioxymethylene and carbonate species as identified by room temperature insitu diffuse reflectance infrared fourier transform spectroscopy.All these results show great potency of this facile ozonation routine for the highly activeδ-MnO_(2)synthesis in order to remove the HCHO contamination.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
Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and ...Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and high energy consumption.Therefore,there is an urgent need to develop efficient supported catalysts that can enhancemass transfer and performance.However,the reaction mechanism of the support on ozone mass transfer remains unclear,which hinders the development of catalytic ozonation applications.In this study,lava rocks(LR)-supported catalysts,specifically CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR,were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity,stability,and high OUE.Addition of CuMn_(2)O_(4)@LR or MnO_(2)–Co_(3)O_(4)@LR increased IBP removal efficiency from 85%to 91%or 88%,and reduced energy consumption from 2.86 to 2.14 kWh/m^(3)or 2.60 kWh/m^(3),respectively.This improvement was attributed to LRsupported catalysts enhancing mass transfer and promoting O3 decomposition to generate•OH and•O_(2)^(−),leading to IBP degradation.Furthermore,this study investigated the effects of ozone dose,supporter sizes,and catalyst components on ozone-liquid mass transfer.The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer.Larger-sized LR(kLa=0.172 min^(−1))exhibited better mass transfer compared to smaller-sized supports.Based on these findings,it was concluded that both CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater,and LR showed good credibility as a catalyst supporter.Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.展开更多
The performance of supported catalysts is significantly affected by the dispersion degree of the active components on the support.In this study,citric acid(CA)was used as a modifier to prepare Al_(2)O_(3)supported Mn-...The performance of supported catalysts is significantly affected by the dispersion degree of the active components on the support.In this study,citric acid(CA)was used as a modifier to prepare Al_(2)O_(3)supported Mn-Ce oxides(Mn-Ce/CA-Al_(2)O_(3))by the impregnation-calcination method.The characterization results showed that adding citric acid enhanced the dispersion of Mn-Ce oxides on the support,rendering Mn-Ce/CA-Al_(2)O_(3)with a larger specific surface area and abundant surface hydroxyl groups,thereby providing more reaction sites for catalytic ozonation.The Mn-Ce/CA-Al_(2)O_(3)exhibited excellent catalytic ozonation performance in degrading Reactive Black 5(RB5)dye.It achieved nearly complete decolorization of RB5 within 60 min,with a COD removal efficiency of 60%,which was superior to the sole ozonation(30%).Furthermore,the Mn-Ce/CA-Al_(2)O_(3)system demonstrated significant degradation of RB5 over a wide pH range of 3e11.Based on the XPS and EPR analysis results,a preliminary mechanism of catalytic ozonation over the Mn-Ce/CA-Al_(2)O_(3)was proposed.The redox cycle of Mn^(3+)/Mn^(4+)and Ce^(3+)/Ce^(4+)effectively accelerated the electron transfer process,thus promoting the generation of reactive oxygen species(ROS)and improving the degradation of RB5.Meanwhile,the Mn-Ce/CA-Al_(2)O_(3)exhibited superior catalytic stability and effective treatment capabilities for real dye wastewater.展开更多
Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains ch...Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains challenging for 2D catalytic ozonation membranes to efficiently degrade micropollutants due to low mass-transfer efficiency and poor catalytic activity.Herein,Fe/Mn bimetallic metal-organic framework(MOF)intercalated lamellar MnO_(2) membranes with fast and robust ozone-catalyzed mass-transfer channels were developed on the surface of the hollow fiber ceramic membrane(HFCM)to obtain 2D Fe/Mn-MOF@MnO_(2)-HFCM for efficiently degrading micropollutants in wastewater.The intercalation of Fe/Mn-MOF expanded the interlayer spacing of the MnO_(2) membrane,thereby providing abundant transport channels for rapid passage of water.More notably,the Fe/Mn-MOF provided enriched reactive sites as well as high electron transfer efficiency based on the redox cycling between Mn^(3+)/Mn^(4+) and Fe^(2+)/Fe^(3+),ensuring the effective catalytic oxidative degradation of micropollutants including tetracycline hydrochloride(TCH),methylene blue,and methyl blue.Moreover,the carboxyl groups on the MOF formed covalent bonds(-COO-)with the hydroxyl groups in MnO_(2) between layers,which increased the interaction between MnO_(2) nanosheets to form stable interlayer channels.Specifically,the optimal composite membrane achieved a high removal rate of TCH micropollutant(93.4%),high water treatment capacity(282 L·m^(-2)·h^(-1)·MPa^(-1)),and excellent longterm stability(1200 min).This study provides a simple and easily scalable strategy to construct fast,efficient,and stable 2D catalytic mass-transfer channels for the efficient treatment of micropollutants in wastewater.展开更多
Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by adva...Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by advanced oxidation processes(AOPs).In this study,ZnO—TiO_(2)nanocomposites were prepared by solgel method,and coated on the disk of SDR by impregnation-pull-drying-calcination method.The performance of catalyst was characterized by X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,photoluminescence and ultraviolet—visible diffuse reflectance spectroscopy.Photocatalytic ozonation in SDR was used to remove phenol,and various factors on degradation effect were studied in detail.The results showed that the rate of degradation and mineralization reached 100%and 83.4%under UV light irradiation after 50 min,compared with photocatalysis and ozonation,the removal rate increased by 69.3%and 34.7%,and mineralization rate increased by 56.7%and 62.9%,which indicated that the coupling of photocatalysis and ozonation had a synergistic effect.The radical capture experiments demonstrated that the active species such as photogenerated holes(h^(+)),hydroxyl radicals(·OH),superoxide radical(·O_(2)-)were responsible for phenol degradation,and·OH played a leading role in the degradation process,while h+and·O_(2)^(-)played a non-leading role.展开更多
As a strong oxidizing agent,ozone is used in some water treatment facilities for disinfection,taste and odor control,and removal of organic micropollutants.Phenylalanine(Phe)was used as the target amino acid to compre...As a strong oxidizing agent,ozone is used in some water treatment facilities for disinfection,taste and odor control,and removal of organic micropollutants.Phenylalanine(Phe)was used as the target amino acid to comprehensively investigate variability of disinfection byproducts(DBPs)formation during chlorine disinfection and residual chlorine conditions subsequent to ozonation.The results showed that subsequent to ozonation,the typical regulated and unregulated DBPs formation potential(DBPsFP),including trichloromethane(TCM),dichloroacetonitrile(DCAN),chloral hydrate(CH),dichloroacetic acid(DCAA),trichloroacetic acid(TCAA),and trichloroacetamide(TCAcAm)increased substantially,by 2.4,3.3,5.6,1.2,2.5,and 6.0 times,respectively,compared with only chlorination.Ozonation also significantly increased the DBPs yield under a 2 day simulated residual chlorine condition that mimicked the water distribution system.DBPs formations followed pseudo first order kinetics.The formation rates of DBPs in the first 6 hr were higher for TCM(0.214 hr^(−1)),DCAN(0.244 hr^(−1)),CH(0.105 hr^(−1)),TCAcAm(0.234 hr^(−1)),DCAA(0.375 hr^(−1))and TCAA(0.190 hr^(−1))than thereafter.The peak DBPsFP of TCM,DCAN,CH,TCAcAm,DCAA,and TCAA were obtained when that ozonation time was set at 5–15 min.Ozonation times>30 min increased the mineralization of Phe and decreased the formation of DBPs upon chlorination.Increasing bromine ion(Br^(−1))concentration increased production of bromine-DBPs and decreased chlorine-DBPs formation by 59.3%–92.2%.Higher ozone dosages and slight alkaline favored to reduce DBP formation and cytotoxicity.The ozonation conditions should be optimized for all application purposes including DBPs reduction.展开更多
Agriculture has a close relationship with nature,but it can also be the source of negative and permanent environmental effects.The use of pesticides in modern agriculture is a common practice,but their side effects on...Agriculture has a close relationship with nature,but it can also be the source of negative and permanent environmental effects.The use of pesticides in modern agriculture is a common practice,but their side effects on the environment cannot be disregarded.In this study,we evaluated a combination of solarization and ozonation techniques for the elimination of six amide pesticides(boscalid,chlorantraniliprole,cyflufenamid,fluopyram,napropamide,and propyzamide)in soil.Initial experiments were performed with four different soils to assess the efficiency of this methodology at different soil temperatures and ozone dosages under laboratory conditions,and then a greenhouse pot experiment was conducted under controlled conditions during summer.Fifty days after the onset of the experiments,higher degradation percentages of amide pesticides were observed in ozonized soils than in other treated soils,particularly when ozone was applied at 10 cm soil depth.The results show that the utilization of ozonation,along with solarization,represents a valid method for degrading residues of the studied pesticides and suggest that this combined technology may be a promising tool for remediating pesticide-polluted soils.展开更多
Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and d...Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.展开更多
To convert the non biodegradable sodium lignin sulfonate into biodegradable substances, the sodium lignin sulfonate in the water was ozonized and the pH value, dissolved organic carbon(DOC), ultraviolet absorbency at...To convert the non biodegradable sodium lignin sulfonate into biodegradable substances, the sodium lignin sulfonate in the water was ozonized and the pH value, dissolved organic carbon(DOC), ultraviolet absorbency at λ =254 nm(UVA) and the biodegradability of the ozonation effluent were measured. The non biodegradable sodium lignin sulfonate can be partly converted into biodegradable substances by ozonation (about 38 76%). In the ozonation process, there is little DOC decrease, but much UVA decrease and obvious pH drop.展开更多
A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbo...A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbon process （GAC） were evaluated based on the following parameters： CODMn, UV254, total organic carbon （TOC）, assimilable organic carbon （AOC） and biodegradable dissolved organic carbon （BDOC）. In this test, the average removal rates of CODMn, UV254 and TOC in O3-BAC were 18.2%, 9.0% and 10.2% higher on （AOC） than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17, 45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2 8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.展开更多
The degradation mechanism of Cationic Red X-GRL was investigated when the intermediates, the nitrate ion and the pH were analyzed in the ozonation. The degradation of the Cationic Red X-GRL includes the de-auxochrome...The degradation mechanism of Cationic Red X-GRL was investigated when the intermediates, the nitrate ion and the pH were analyzed in the ozonation. The degradation of the Cationic Red X-GRL includes the de-auxochrome stage, the decolour stage, and the decomposition of fragment stage. During the degradation process, among the six nitrogen atoms of Cationic Red X-GRL, one is transferred into a nitrate ion, one becomes the form of an amine compound, and the rest four are transformed into two molecules of nitrogen. In the course of the ozonation of Cationic Red X-GRL, the direct attack of ozone is the main decolour effect.展开更多
A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continu...A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min 1,respectively.The phenolic treatment results in seven cases were compared：（a）O3 only,（b）fresh granular activated carbon（GAC）,（c） 1st reused GAC,（d）2nd reused GAC,（e）fresh GAC enhanced with O3,（f）1st reused GAC enhanced with O3,and （g）2nd reused GAC enhanced with O3.The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time.The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result.The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone.Fresh GAC could adsorb phenol better than reused GAC.All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics.Finally,a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3.The calculated results agree reasonably well with the experimental results.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
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
A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon （Cu/AC） that was prepared by an incipient wetness impregnation method at low temperature and te...A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon （Cu/AC） that was prepared by an incipient wetness impregnation method at low temperature and tested as a catalyst in the ozonation of phenol and oxalic acid. Cu/AC was characterized using XRD, BET and SEM techniques. Compared with ozonation alone, the presence of Cu/AC in the ozonation processes significantly improves the degradation of phenol or oxalic acid. With the introduction of the hydroxyl radical scavenger, i.e., turt-butanol alcohol （t-BuOH）, the degradation efficiency of both phenol and oxalic acid in the Cu/AC catalyzed ozonation process decreases by 22% at 30 min. This indicates that Cu/AC accelerates ozone decomposition into certain concentration of hydroxyl radicals. The amount of Cu（II ） produced during the reaction of Cu/AC-catalyzed ozonation of phenol or oxalic acid is very small, which shows that the two processes are both heterogeneous catalytic ozonation reactions.展开更多
基金supported by the National Natural Science Foundation of China(No.22206013).
文摘The efficient mineralization of phenol and its derivatives in wastewater remains a great challenge.In this study,the bimetallic CuCeO_(2)-BTC was screened from a series of MOFs-derived MCeO_(2)-BTC(M=La,Cu,Co,Fe,and Mn)catalysts,and the influence of the Cu/Ce ratio on phenol removal by catalytic ozonation was carefully examined.The results indicate that Cu_(2)Ce_(1)O_(y)-BTC was the best among the Cu_(x)Ce_(1)O_(y)-BTC(x=0,1,2,and 3)catalysts,with a phenol mineralization efficiency reaching close to 100%within 200 min,approximately 30.1%higher than CeO_(2)-BTC/O_(3)and 70.3%higher than O_(3)alone.The order of mineralization efficiency of phenol was Cu_(2)Ce_(1)O_(y)-BTC>Cu_(3)Ce_(1)O_(y)-BTC>Cu_(1)Ce_(1)O_(y)-BTC>CeO_(2)-BTC.CeO_(2)-BTC exhibited a broccoli-like morphology,and Cu_(x)Ce_(1)O_(y)-BTC(x=1,2,and 3)exhibited an urchin-like morphology.Compared with Cu_(x)Ce_(1)O_(y)-BTC(x=0,1,and 3),Cu_(2)Ce_(1)O_(y)-BTC exhibited a larger specific surface area and pore volume.This characteristic contributed to the availability of more active sites for phenol degradation.The redox ability was greatly enhanced as well.Besides,the surface of Cu_(2)Ce_(1)O_(y)-BTC exhibited a higher concentration of Ce^(3+)species and hydroxyl groups,which facilitated the dissociation of ozone and the generation of active radicals.Based on the results of radical quenching experiments and the intermediates detected by LC-MS,a potential mechanism for phenol degradation in the Cu_(2)Ce_(1)O_(y)-BTC/O_(3)system was postulated.This study offers novel perspectives on the advancement of MOFs-derived catalysts for achieving the complete mineralization of phenol in wastewater through catalytic ozonation.
基金Project(2022M710619)supported by the Postdoctoral Science Foundation of ChinaProjects(2020YFH0213,2020YFG0039)supported by the Sichuan Science and Technology Program,China+1 种基金Projects(XJ2024001501,KCXTD2023-4)supported by the Basic Scientific Foundation and Innovation Team Funds of China West Normal UniversityProject(CSPC202403)supported by the Open Project Program of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province,China。
文摘In response to the fact that the presence of manganese dithionate(MnS_(2)O_(6))leads to a series of adverse impacts,especially lower purity of manganese sulfate(MnSO_(4))and disruption of its recovery,advanced oxidation methods such as ozonation system are used to manage MnS_(2)O_(6)in the leaching solution,replacing conventional methods.To ascertain the conversion rate and kinetics of MnS_(2)O_(6)during the ozonation process,we explored the factors influencing its removal rate,including ozone dosage,manganese dithionate concentration,sulfuric acid concentration,and reaction temperature.Batch experiments were conducted to determine the reaction rate constant of ozone(k)and activation energy(Ea)obtained from intermittent experimental data fitting,revealing a least-squares exponential conversion relationship between k and the MnS_(2)O_(6)removal amount,wherein an increase in the aforementioned factors led to an enhanced MnS_(2)O_(6)conversion rate,exceeding 99.3%.The formation mechanism of the ozone products proposed during the experiment was summarized and proposed as follows:1)Mn^(2+)was directly oxidized to MnO_(2),and 2)SO_(4)2−was obtained by the catalytic oxidation of S_(2)O_(6)^(2−)with HO•from O3 decomposition.According to the kinetics analysis,the pre-exponential factor and total activation energy of the ozonation kinetics equation were 1.0×10^(23) s^(−1) and 177.28 kJ/mol,respectively.Overall,the present study demonstrates that O_(3) as an oxidizing agent can effectively facilitate MnS_(2)O_(6)disproportionation while preventing the release of the secondary pollutant,SO_(2)gas.
基金supported by the National Natural Science Foundation of China(Nos.52270073 and 51708292)。
文摘This study aims to identify the highly non-specific toxic by-products during ozonation of three cresols in wastewater.In ozonated effluents,biotoxicity increased along with increasing reaction time,followed by a gradual decrease.The peak biotoxicity for ozonated o-cresol(o-C),m-cresol(m-C),and p-cresol(p-C)was estimated to be 17.4,14.8 and 5.5 times higher than that of untreated wastewater,respectively.A redox-directed approach with high-resolution mass spectrometry detection and toxicity prediction revealed that monomeric para-benzoquinones(p-BQs),hydroxylated p-BQs,and dimeric p-BQs in ozonated cresols were the primary contributors to the increased toxicity.Calculations based on density functional theory indicated formation pathways of p-BQs byproducts,e.g.,the formation of 2-methyl-p-benzoquinone was likely induced by ozone molecules rather than hydroxyl radicals in ozonated o-C and m-C,and the formation of p-BQs during ozonation of p-C was attributed to the oxidation of methyl group to carboxyl group and subsequent decarboxylation initiated by hydroxyl radicals.Electron paramagnetic resonance and spin density calculation showed that the presence of carbon-centered cresoxyl radicals was responsible for dimeric p-BQs formation.Collectively,these results underscore significant contribution of non-halogenated p-BQs to non-specific toxicity increase in ozonated effluents.
文摘Photocatalytic ozonation holds promise for advanced water purification,yet its development has been hindered by a limited understanding of ozone activation mechanisms and its related photogenerated electron transfer dynamics.Herein,we employed in-situ DRIFTS and Raman spectroscopy to elucidate the distinct adsorption and activation behaviors of ozone(O_(3))on the{001}and{110}crystal facets of Bi_(2)O_(2)CO_(3)(BOC)nanosheets.BOC-{001}demonstrates superior photocatalytic ozonation performance,with 85%phenol mineralization and excellent durability,significantly outperforming the 53%mineralization rate of BOC-{110}.This enhanced activity is attributed to non-dissociative ozone adsorption and favorable adsorption energy over{001}facet,which facilitate the one-electron O_(3) reduction pathway.Furthermore,crystal facet engineering strengthens the built-in electric field,promoting exciton dissociation and the generation of localized charge carriers.The synergistic effects of optimized electron availability and ozone adsorption significantly boost the production of reactive oxygen species.These findings provide a deeper understanding of the critical roles of O_(3) adsorption and electron transfer in radical generation,which could provide some guidance for the strategic development of highly effective photocatalytic ozonation catalysts.
基金supported by the National Key Research and Development Program of China(No.2016YFC0207100).
文摘Nowadays,it is still a challenge to prepared high efficiency and low cost formaldehyde(HCHO)removal catalysts in order to tackle the long-living indoor air pollution.Herein,δ-MnO_(2)is successfully synthesized by a facile ozonation strategy,where Mn^(2+)is oxidized by ozone(O_(3))bubble in an alkaline solution.It presents one of the best catalytic properties with a low 100%conversion temperature of 85℃for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr).As a comparison,more than 6 times far longer oxidation time is needed if O3 is replaced by O_(2).Characterizations show that ozonation process generates a different intermediate of tetragonalβ-HMnO_(2),which would favor the quick transformation into the final productδ-MnO_(2),as compared with the relatively more thermodynamically stable monoclinicγ-HMnO_(2)in the O_(2)process.Finally,HCHO is found to be decomposed into CO_(2)via formate,dioxymethylene and carbonate species as identified by room temperature insitu diffuse reflectance infrared fourier transform spectroscopy.All these results show great potency of this facile ozonation routine for the highly activeδ-MnO_(2)synthesis in order to remove the HCHO contamination.
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 Key Research and Development Program of China(No.2021YFE0100800)the National Natural Science Foundation of China(Nos.22076012,52100002,52200035,and 51878047)+4 种基金the Beijing Forestry University Outstanding Young Talent Cultivation Project(No.2019JQ03008)the Yangtze River Joint Research Phase II Program(Nos.2022-LHYJ-02-0510-02,and 2022-LHYJ-02-0502-02-06)the Open Project of State Key Laboratory of Urban Water Resources and Environment(No.HC202328)the Fundamental Research Funds for the Central Universities(No.BLX202153)the China Postdoctoral Science Foundation(No.2021M700448).
文摘Catalytic ozonation is an effective wastewater purification process.However,the low ozone mass transfer in packed bubble columns leads to low ozone utilization efficiency(OUE),poor organic degradation performance,and high energy consumption.Therefore,there is an urgent need to develop efficient supported catalysts that can enhancemass transfer and performance.However,the reaction mechanism of the support on ozone mass transfer remains unclear,which hinders the development of catalytic ozonation applications.In this study,lava rocks(LR)-supported catalysts,specifically CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR,were proposed for catalytic ozonation of IBP degradation due to their superior catalytic activity,stability,and high OUE.Addition of CuMn_(2)O_(4)@LR or MnO_(2)–Co_(3)O_(4)@LR increased IBP removal efficiency from 85%to 91%or 88%,and reduced energy consumption from 2.86 to 2.14 kWh/m^(3)or 2.60 kWh/m^(3),respectively.This improvement was attributed to LRsupported catalysts enhancing mass transfer and promoting O3 decomposition to generate•OH and•O_(2)^(−),leading to IBP degradation.Furthermore,this study investigated the effects of ozone dose,supporter sizes,and catalyst components on ozone-liquid mass transfer.The results revealed that the size of the supporter influenced stacked porosity and consequently affected ozone mass transfer.Larger-sized LR(kLa=0.172 min^(−1))exhibited better mass transfer compared to smaller-sized supports.Based on these findings,it was concluded that both CuMn_(2)O_(4)@LR and MnO_(2)–Co_(3)O_(4)@LR are potential catalysts for catalytic ozonation in residual IBP degradation of pharmaceutical wastewater,and LR showed good credibility as a catalyst supporter.Understanding the effects of supporters and active components on ozone mass transfer provides a fundamental principle for designing supported catalysts in catalytic ozonation applications.
基金supported by the National Key Research and Development Program(2023YFC3207003)the National Natural Science Foundation of China(51878448).
文摘The performance of supported catalysts is significantly affected by the dispersion degree of the active components on the support.In this study,citric acid(CA)was used as a modifier to prepare Al_(2)O_(3)supported Mn-Ce oxides(Mn-Ce/CA-Al_(2)O_(3))by the impregnation-calcination method.The characterization results showed that adding citric acid enhanced the dispersion of Mn-Ce oxides on the support,rendering Mn-Ce/CA-Al_(2)O_(3)with a larger specific surface area and abundant surface hydroxyl groups,thereby providing more reaction sites for catalytic ozonation.The Mn-Ce/CA-Al_(2)O_(3)exhibited excellent catalytic ozonation performance in degrading Reactive Black 5(RB5)dye.It achieved nearly complete decolorization of RB5 within 60 min,with a COD removal efficiency of 60%,which was superior to the sole ozonation(30%).Furthermore,the Mn-Ce/CA-Al_(2)O_(3)system demonstrated significant degradation of RB5 over a wide pH range of 3e11.Based on the XPS and EPR analysis results,a preliminary mechanism of catalytic ozonation over the Mn-Ce/CA-Al_(2)O_(3)was proposed.The redox cycle of Mn^(3+)/Mn^(4+)and Ce^(3+)/Ce^(4+)effectively accelerated the electron transfer process,thus promoting the generation of reactive oxygen species(ROS)and improving the degradation of RB5.Meanwhile,the Mn-Ce/CA-Al_(2)O_(3)exhibited superior catalytic stability and effective treatment capabilities for real dye wastewater.
基金supported by the National Key Research and Development Program(2021YFB3801303)the National Natural Science Foundation of China(22408161,21921006)+1 种基金the Key Research and Development Program of Jiangsu Provincial Department of Science and Technology(BE2022033-3)the State Key Laboratory of Materials-Oriented Chemical Engineering(SKL-MCE-22A03).
文摘Two-dimensional(2D)catalytic ozonation membranes are promising for the treatment of micropollutants in wastewater due to simultaneous ozone-catalyzed degradation and membrane filtration processes.However,it remains challenging for 2D catalytic ozonation membranes to efficiently degrade micropollutants due to low mass-transfer efficiency and poor catalytic activity.Herein,Fe/Mn bimetallic metal-organic framework(MOF)intercalated lamellar MnO_(2) membranes with fast and robust ozone-catalyzed mass-transfer channels were developed on the surface of the hollow fiber ceramic membrane(HFCM)to obtain 2D Fe/Mn-MOF@MnO_(2)-HFCM for efficiently degrading micropollutants in wastewater.The intercalation of Fe/Mn-MOF expanded the interlayer spacing of the MnO_(2) membrane,thereby providing abundant transport channels for rapid passage of water.More notably,the Fe/Mn-MOF provided enriched reactive sites as well as high electron transfer efficiency based on the redox cycling between Mn^(3+)/Mn^(4+) and Fe^(2+)/Fe^(3+),ensuring the effective catalytic oxidative degradation of micropollutants including tetracycline hydrochloride(TCH),methylene blue,and methyl blue.Moreover,the carboxyl groups on the MOF formed covalent bonds(-COO-)with the hydroxyl groups in MnO_(2) between layers,which increased the interaction between MnO_(2) nanosheets to form stable interlayer channels.Specifically,the optimal composite membrane achieved a high removal rate of TCH micropollutant(93.4%),high water treatment capacity(282 L·m^(-2)·h^(-1)·MPa^(-1)),and excellent longterm stability(1200 min).This study provides a simple and easily scalable strategy to construct fast,efficient,and stable 2D catalytic mass-transfer channels for the efficient treatment of micropollutants in wastewater.
基金supported by the National Natural Science Foundation of China(22208328)Fundamental Research Program of Shanxi Province(20210302124618,202203021212134)。
文摘Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by advanced oxidation processes(AOPs).In this study,ZnO—TiO_(2)nanocomposites were prepared by solgel method,and coated on the disk of SDR by impregnation-pull-drying-calcination method.The performance of catalyst was characterized by X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,photoluminescence and ultraviolet—visible diffuse reflectance spectroscopy.Photocatalytic ozonation in SDR was used to remove phenol,and various factors on degradation effect were studied in detail.The results showed that the rate of degradation and mineralization reached 100%and 83.4%under UV light irradiation after 50 min,compared with photocatalysis and ozonation,the removal rate increased by 69.3%and 34.7%,and mineralization rate increased by 56.7%and 62.9%,which indicated that the coupling of photocatalysis and ozonation had a synergistic effect.The radical capture experiments demonstrated that the active species such as photogenerated holes(h^(+)),hydroxyl radicals(·OH),superoxide radical(·O_(2)-)were responsible for phenol degradation,and·OH played a leading role in the degradation process,while h+and·O_(2)^(-)played a non-leading role.
基金This research is supported by the National Natural Science Foundation of China(No.51678527)the Natural Science Foundation of Zhejiang Province of China(No.LY19E080019)+1 种基金the Xinmiao Talent Program of Zhejiang Province(No.2022R403C093)Engineering Research Center of Ministry of Education for Renewable Energy Infrastructure Construction Technology.
文摘As a strong oxidizing agent,ozone is used in some water treatment facilities for disinfection,taste and odor control,and removal of organic micropollutants.Phenylalanine(Phe)was used as the target amino acid to comprehensively investigate variability of disinfection byproducts(DBPs)formation during chlorine disinfection and residual chlorine conditions subsequent to ozonation.The results showed that subsequent to ozonation,the typical regulated and unregulated DBPs formation potential(DBPsFP),including trichloromethane(TCM),dichloroacetonitrile(DCAN),chloral hydrate(CH),dichloroacetic acid(DCAA),trichloroacetic acid(TCAA),and trichloroacetamide(TCAcAm)increased substantially,by 2.4,3.3,5.6,1.2,2.5,and 6.0 times,respectively,compared with only chlorination.Ozonation also significantly increased the DBPs yield under a 2 day simulated residual chlorine condition that mimicked the water distribution system.DBPs formations followed pseudo first order kinetics.The formation rates of DBPs in the first 6 hr were higher for TCM(0.214 hr^(−1)),DCAN(0.244 hr^(−1)),CH(0.105 hr^(−1)),TCAcAm(0.234 hr^(−1)),DCAA(0.375 hr^(−1))and TCAA(0.190 hr^(−1))than thereafter.The peak DBPsFP of TCM,DCAN,CH,TCAcAm,DCAA,and TCAA were obtained when that ozonation time was set at 5–15 min.Ozonation times>30 min increased the mineralization of Phe and decreased the formation of DBPs upon chlorination.Increasing bromine ion(Br^(−1))concentration increased production of bromine-DBPs and decreased chlorine-DBPs formation by 59.3%–92.2%.Higher ozone dosages and slight alkaline favored to reduce DBP formation and cytotoxicity.The ozonation conditions should be optimized for all application purposes including DBPs reduction.
基金supported by the European Commission through the LIFE+Program(No.LIFE-AgRemSO3il 17 ENV/ES/000203)。
文摘Agriculture has a close relationship with nature,but it can also be the source of negative and permanent environmental effects.The use of pesticides in modern agriculture is a common practice,but their side effects on the environment cannot be disregarded.In this study,we evaluated a combination of solarization and ozonation techniques for the elimination of six amide pesticides(boscalid,chlorantraniliprole,cyflufenamid,fluopyram,napropamide,and propyzamide)in soil.Initial experiments were performed with four different soils to assess the efficiency of this methodology at different soil temperatures and ozone dosages under laboratory conditions,and then a greenhouse pot experiment was conducted under controlled conditions during summer.Fifty days after the onset of the experiments,higher degradation percentages of amide pesticides were observed in ozonized soils than in other treated soils,particularly when ozone was applied at 10 cm soil depth.The results show that the utilization of ozonation,along with solarization,represents a valid method for degrading residues of the studied pesticides and suggest that this combined technology may be a promising tool for remediating pesticide-polluted soils.
文摘Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.
文摘To convert the non biodegradable sodium lignin sulfonate into biodegradable substances, the sodium lignin sulfonate in the water was ozonized and the pH value, dissolved organic carbon(DOC), ultraviolet absorbency at λ =254 nm(UVA) and the biodegradability of the ozonation effluent were measured. The non biodegradable sodium lignin sulfonate can be partly converted into biodegradable substances by ozonation (about 38 76%). In the ozonation process, there is little DOC decrease, but much UVA decrease and obvious pH drop.
文摘A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbon process （GAC） were evaluated based on the following parameters： CODMn, UV254, total organic carbon （TOC）, assimilable organic carbon （AOC） and biodegradable dissolved organic carbon （BDOC）. In this test, the average removal rates of CODMn, UV254 and TOC in O3-BAC were 18.2%, 9.0% and 10.2% higher on （AOC） than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17, 45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2 8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.
文摘The degradation mechanism of Cationic Red X-GRL was investigated when the intermediates, the nitrate ion and the pH were analyzed in the ozonation. The degradation of the Cationic Red X-GRL includes the de-auxochrome stage, the decolour stage, and the decomposition of fragment stage. During the degradation process, among the six nitrogen atoms of Cationic Red X-GRL, one is transferred into a nitrate ion, one becomes the form of an amine compound, and the rest four are transformed into two molecules of nitrogen. In the course of the ozonation of Cationic Red X-GRL, the direct attack of ozone is the main decolour effect.
基金Supported by the National Nanotechnology Center(NANOTEC)(601003)the National Science and Technology Development Agency(NSTDA)
文摘A three phase fluidized bed reactor was used to investigate the combined effect of adsorption and oxidation for phenolic wastewater treatment.Aqueous solutions containing 10 mg·L 1of phenol and ozone were continuously fed co-currently as upward flow into the reactor at constant flow rate of 2 and 1 L·min 1,respectively.The phenolic treatment results in seven cases were compared：（a）O3 only,（b）fresh granular activated carbon（GAC）,（c） 1st reused GAC,（d）2nd reused GAC,（e）fresh GAC enhanced with O3,（f）1st reused GAC enhanced with O3,and （g）2nd reused GAC enhanced with O3.The phenolic wastewater was re-circulated through the reactor and its concentration was measured with respect to time.The experimental results revealed that the phenolic degradation using GAC enhanced with O3 provided the best result.The effect of adsorption by activated carbon was stronger than the effect of oxidation by ozone.Fresh GAC could adsorb phenol better than reused GAC.All cases of adsorption on GAC followed the Langmuir isotherm and displayed pseudo second order adsorption kinetics.Finally,a differential equation for the fluidized bed reactor model was used to describe the phenol concentration with respect to time for GAC enhanced with O3.The calculated results agree reasonably well with the experimental results.
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 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Project(40973074) supported by the National Natural Science Foundation of China
文摘A novel heterogeneous catalytic ozonation process in water treatment was studied, with a copper-loaded activated carbon （Cu/AC） that was prepared by an incipient wetness impregnation method at low temperature and tested as a catalyst in the ozonation of phenol and oxalic acid. Cu/AC was characterized using XRD, BET and SEM techniques. Compared with ozonation alone, the presence of Cu/AC in the ozonation processes significantly improves the degradation of phenol or oxalic acid. With the introduction of the hydroxyl radical scavenger, i.e., turt-butanol alcohol （t-BuOH）, the degradation efficiency of both phenol and oxalic acid in the Cu/AC catalyzed ozonation process decreases by 22% at 30 min. This indicates that Cu/AC accelerates ozone decomposition into certain concentration of hydroxyl radicals. The amount of Cu（II ） produced during the reaction of Cu/AC-catalyzed ozonation of phenol or oxalic acid is very small, which shows that the two processes are both heterogeneous catalytic ozonation reactions.
