Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to ...Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to enhance the photodegradation efficiency of photocatalysts for pollutants,being due that this strategy can effectively suppress the recombination of the photo-induced electron and hole.In this research,a novel double Z-scheme BN/C_(60)/g-C_(3)N_(4) heterojunction was successfully synthesized via one-step synthetic approach.Based on a series of experimental characterization,BN/C_(60)/g-C_(3)N_(4) is most likely formed via the interaction between N element of BN and g-C_(3)N_(4) with C_(60) under UV-light irradiation.The band structures of BN,C_(60),g-C_(3)N_(4) and the internal electric field among them suggest that BN/C_(60)/g-C_(3)N_(4) may has a direct double z-type band arrangement,which facilitates efficient charge transfer.The photodegradation rate of BN/C_(60)/g-C_(3)N_(4) for tetracycline reached 90.1%,which is 2.9 times higher than that observed with BN and 2.3 times higher than that of g-C_(3)N_(4).BN/C_(60)/g-C_(3)N_(4) exhibits remarkable photocatalytic performance across a wide pH range and in the influence of different anions.This study offers significant insights about how to design double z-scheme metal-free photocatalyst with high photodegradation efficiency for antibiotic.展开更多
It has been challenging for Fe(Ⅲ)regeneration in Fe-based photocatalysts for continuous peroxydisulfate(PDS)activation due to the lower ability to reduce Fe(Ⅲ).In this work,Fe-doped ultrathin VO_(2)(Fe-VO_(2))nanobe...It has been challenging for Fe(Ⅲ)regeneration in Fe-based photocatalysts for continuous peroxydisulfate(PDS)activation due to the lower ability to reduce Fe(Ⅲ).In this work,Fe-doped ultrathin VO_(2)(Fe-VO_(2))nanobelts were synthesized for purifying metronidazole(MNZ)via PDS activation.As an efficient Fentonlike catalyst for PDS activation,2 wt%Fe-doped VO_(2)can remove 98%of MNZ within 40 min and exhibits impressive recyclability.The synergistic effect of Fe-VO_(2)and Fe(Ⅲ)activated PDS boosted the photocatalytic performance.Moreover,SO_(4)•^(−),h+,O_(2)•^(−),^(1)O_(2),and•OH were the main reactive radicals.The effects of initial MNZ concentration,Fe-VO_(2),PDS dosage,and various anions/cations on MNZ removal by the Fe-VO_(2)/PDS/Vis system were studied.The intermediates of MNZ degradation and possible pathways were determined by density function theory(DFT)calculations and HPLC-MS.This study provided a sustainable technology using Fe-doped ultrathin VO_(2)nanobelts for photocatalytic PDS activation and decontamination of pharmaceutical wastewater.展开更多
Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composit...Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composite was evaluated using the degradation of rhodamine B(RhB)and tetracycline hydrochloride(TCH)under visible light.The results demonstrated that Ti_(3)C_(2)/BOC composite had higher photocatalytic activity than pure BOC.The optimum incorporation amount of Ti_(3)C_(2) was 2 wt%.The photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC at 10 min to 20 mg/L RhB was 97.6%,which was much higher than that of BOC(75.3%).Similarly,the photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC to 10 mg/L TCH at 30 min was 80.4%,which was higher than BOC(68.1%).In addition,the prepared 2 wt%-Ti_(3)C_(2)/BOC composite also maintained good stability even after four cycles.Electrochemical impedance spectroscopy(EIS),transient photocurrent response(IT)and ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)confirmed that the photoelectrochemical properties of 2 wt%-Ti_(3)C_(2)/BOC composite were significantly improved.On the basis of analyzing the action mechanism of photocatalyst,it was pointed out that·O_(2)^(-)and h~+were the main active substances in the photodegradation of RhB and TCH by 2 wt%-Ti_(3)C_(2)/BOC.展开更多
The edge-graphitized carbon nitride(C_(3)N_(4)-C g)was prepared by secondary pyrolysis to construct ZnO/C_(3)N_(4)-C g(ZCN)type-Ⅱheterojunction photocatalyst via a facile sonication dispersion method,which achieved∼...The edge-graphitized carbon nitride(C_(3)N_(4)-C g)was prepared by secondary pyrolysis to construct ZnO/C_(3)N_(4)-C g(ZCN)type-Ⅱheterojunction photocatalyst via a facile sonication dispersion method,which achieved∼7.04-fold and∼18.3-fold enhanced visible-light-driven photocatalytic performance for refrac-tory micropollutant removal and simultaneous hydrogen(H_(2))evolution respectively compared to con-ventional ZnO/g-C_(3)N_(4)Step-scheme heterojunction.The apparent quantum efficiency of the ZCN_(0.4)het-erojunction reaches 0.92%(λ=420 nm).Such excellent performance stems from that the edge-graphene moieties stitched onto the interface of heterojunction extend light absorption to the full visible spec-trum,meanwhile,the built-in electric field generated during Fermi level alignment accompanying fa-vorable band-bending structure provides an effective pathway for the rapid migration of photoinduced electrons via the edge graphene channel to improve interfacial charge separation efficiency.Interestingly,the midgap states introduced in ZCN heterojunction could temporarily retain photoexcited electrons to effectively inhibit the in situ carrier recombination for improved photocatalytic H_(2)evolution.Moreover,ZCN/peroxymonosulfate system exhibited excellent anti-interference performance against complex water bodies under visible illumination due to the synergistic effect between the co-existing anions and organic matter.Meanwhile,the eco-friendly nature of the ZCN/peroxymonosulfate system showed no biotoxicity of reaction filtrate on cell proliferation after treatment,which avoided secondary contamination.Consid-ering the outstanding performance in photocatalysis,the ZCN system exhibits broad potential for practical applications in water pollution control and green energy production.展开更多
La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy ...La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy dispersive X-ray,transmission electron microscopy,UV-vis diffuse reflectance spectroscopy and photo luminescence spectroscopy.The La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for ZnLC.Under simulated solar light irradiation,the ZnO doped with 3 at%La and 1 at%Ce(ZnLC1)degrades methylene blue(MB)more effectively than those of pure ZnO,La-doped ZnO(ZnL)and commercially available ZnO.The improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence spectra.Additionally,the photocatalytic experiments reveal that several parameters have their own impact on the MB degradation.Using a variety of radical scavengers,it is discovered that superoxide anion radical plays a crucial role in the degradation of MB.The ZnLC1 is also reused several times without noticeable decrease of photoactivity,indicating that it has a substantial potential for environmental remediation applications.展开更多
Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health ...Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still unclear.Here,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light sources.Xe lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 min.The xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and carbonyls.Among them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of xylenes.Moreover,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure risk.Therefore,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded xylenes.The findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.展开更多
Developing high-efficiency photocatalysts for tetracycline hydrochloride(TCH)degradation is of great sig-nificance to ecosystems and human beings.In this work,a two-step process of exfoliation and re-stacking was perf...Developing high-efficiency photocatalysts for tetracycline hydrochloride(TCH)degradation is of great sig-nificance to ecosystems and human beings.In this work,a two-step process of exfoliation and re-stacking was performed to prepare re-stacked HTiNbO_(5) nanosheets(R-HTNS)and then coupled with Ti_(3)C_(2) MXene to construct Ti_(3)C_(2) MXene/R-HTNS(MX/RTS)with a 2D/2D Schottky heterojunction.These 2D/2D het-erostructures between Ti_(3)C_(2) MXene and R-HTNS can produce an internal electric field and provide max-imum interface area for efficient charge transfer across the intimate interface.The photocatalytic perfor-mance of samples was evaluated by TCH degradation under simulated sunlight.The MX/RTS composites,with an optimal sample of 3-MX/RTS,show enhanced photocatalytic activity for TCH degradation com-pared with R-HTNS.The characterization results reveal that the introduction of Ti_(3)C_(2) MXene can signif-icantly increase specific surface area for providing more reactive sites and broaden the light absorption region.Besides,the incident light energy is absorbed by the Ti_(3)C_(2) MXene component in MX/RTS compos-ites to generate photothermal energy(heat),which facilitates the charge carrier separation and surface reaction kinetics.Thus,the enhanced TCH photodegradation activity for MX/RTS composites is due to the introduction of Ti_(3)C_(2) MXene,which possesses the synergistic effect of the increased specific surface area,improved light-harvesting capacity,2D/2D Schottky heterojunction,and photothermal energy effect.Additionally,the TCH photodegradation behavior is deliberated with a detailed discussion on various co-existing ions.During TCH photodegradation,the active radical species are determined for 3-MX/RTS.Ac-cording to the characterization results,the possible TCH photodegradation pathway and mechanism over 3-MX/RTS are explored.This work may offer a novel insight for constructing MXene-based heterostruc-tured photocatalysts with high efficiency.展开更多
Semiconductor heterojunction engineering and three-dimensional(3D)architecture con-struction have been considered highly desirable strategies to enhance photocatalytic perfor-mance.Herein,a BiOI/ZnO composite photocat...Semiconductor heterojunction engineering and three-dimensional(3D)architecture con-struction have been considered highly desirable strategies to enhance photocatalytic perfor-mance.Herein,a BiOI/ZnO composite photocatalyst with a 3D flower-like architecture was successfully prepared,whichwas stably immobilized on three-dimensional porous lignocel-lulosic biomass Juncus effusus(JE)fiber.The outstanding photocatalytic performance of the BiOI/ZnO-JE fiber was confirmed by the degradation of tetracycline hydrochloride(TC,90%),ciprofloxacin(CIP,79%),and norfloxacin(NOR,81%).The enhanced photocatalytic activities were mainly attributed to the synergistic absorption performance of the lignocellulosic JE and the effective transfer and separation of charges.Moreover,the hydroxyl(·OH)and super-oxide radicals(·O_(2)^(−))are themain reactive species in the photocatalytic process according to the analysis.This work may provide a novel perspective for constructing high-performance lignocellulosic-based photocatalytic materials.展开更多
We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is ...We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is better than that for methylene blue(MB)(28%)under irradiation.These levels are both better than DBC degradation performances for TC(68%)and MB(18%)under irradiation.Reactive species quenching experiments suggest that h and-O,are the main reactive species for NDBC photodegraded TC,while-OH and h*are the main reactive species for NDBC photodegraded MB.-OH is not observed during DBC photodegradation of MB.This is likely because N-doping increases valence-band(VB)energy from 1.55 eV in DBC to 2.04 eV in NDBC;the latter is strong enough to oxidize water to form-OH.Additionally,N-doping increases the DBC band gap of 2.29 to 2.62 eV in NDBC,resulting in a higher separation efficiency of photo-generated electrons-holes in NDBC than in DBC.AIl these factors give NDBC stronger photodegradation performance for TC and MB than DBC.High-performance liquid chromatography-mass spectrometry(HPLC-MS)characterization and toxicity evaluation with the quantitative structure-activity relationship(QSAR)method suggest that TC photodegradation intermediates produced by NDBC have less aromatic structure and are less toxic than those produced by DBC.We adopted a theoretical approach to clarify the relationship between the surface groups of NDBC and the photoactive species produced.Our results add to the understanding of the photochemical behavior of NDBC.展开更多
The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method ...The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.展开更多
Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH4F(mass fraction) separately. The results show that TiO2 nanotubes can be formed on Ti foil by both processes, whe...Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH4F(mass fraction) separately. The results show that TiO2 nanotubes can be formed on Ti foil by both processes, whereas TiO2 nanotubes can be formed on porous Ti only in the second process. The overhigh current density led to the failure of the formation nanotubes on porous Ti in 0.5%HF electrolyte. TiO2 nanotubes were characterized by SEM and XRD. TiO2 nanotubes on porous Ti were thinner than those on Ti foil. Anatase was formed when TiO2 nanotubes were annealed at 400 °C and fully turned into rutile at 700 °C. To obtain good photodegradation, the optimal heat treatment temperature of TiO2 nanotubes was 450 °C. The porosity of the substrates influenced photodegradation properties. TiO2 nanotubes on porous Ti with 60% porosity had the best photodegradation.展开更多
Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity ...Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity of the composites were evaluated by their ability to photodegrade methylene blue and dimethyl phthalate（DMP） under visible-light irradiation. Compared with pure V2O5 and MoO 3,the V2O5/MoO 3 composites showed enhanced visible-light photocatalytic activity because of a V 3d impurity energy level and the formation of heterostructures at the interface between V2O5 and MoO 3. The optimal molar ratio of V to Mo in the V2O5/MoO 3 composites was found to be around 1/2. Furthermore,high-performance liquid chromatographic monitoring revealed that phthalic acid was the main intermediate in the photocatalytic degradation process of DMP.展开更多
To advance the knowledge of the environmental fate of sulfamethoxazole （SMX）, we systematically investigated the effects of natural water constituents and synthetic substances （i.e., TiO2 nanoparticles （nTiO2） an...To advance the knowledge of the environmental fate of sulfamethoxazole （SMX）, we systematically investigated the effects of natural water constituents and synthetic substances （i.e., TiO2 nanoparticles （nTiO2） and Ti-doped ^-Bi203 （NTB）） on the photodegradation kinetics of SMX under xenon lamp irradiation. The photolysis of SMX in aqueous solution followed first-order kinetics. Our results showed that higher concentrations of SMX, fulvic acid, suspended sediments, NTB and higher pH value decreased the photodegradation rates of SMX, whereas H202 improved the SMX photodegradation. TiO2 nanoparticles had a dual effect on pbotodegradation due to their photocatalytic activity and photoabsorption of photons. No intermediates more toxic toward Vibrio fischeri than SMX were produced after direct photolysis and photocatalytic degradation for 3 hr. The photolysis of SMX involved three pathways： hydroxylation, cleavage of the sulfonamide bond, and fragmentation of the isoxazole ring. This study lays the groundwork for a better understanding of the environmental fate of SMX.展开更多
Benzotriazole UV stabilizers (BT-UVs) have attracted concems due to their ubiquitous occurrence in the aquatic environment,and their bioaccumulative and toxic properties.However,little is known about their aquatic env...Benzotriazole UV stabilizers (BT-UVs) have attracted concems due to their ubiquitous occurrence in the aquatic environment,and their bioaccumulative and toxic properties.However,little is known about their aquatic environmental degradation behavior.In this study,photodegradation of a representative of BT-UVs,2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P),was investigated under simulated sunlight irradiation.Results show that UV-P photodegrades slower under neutral conditions (neutral form) than under acidic or alkaline conditions (cationic and anionic forms).Indirect photodegradation is a dominant elimination pathway of UV-P in coastal seawaters.Dissolved organic matter (DOM) from seawaters accelerate the photodegradation rates mainly through excited triplet DOM (3DOM*),and the roles of singlet oxygen and hydroxyl radical are negligible in the matrixes.DOM from seawaters impacted by mariculture exhibits higher steady-state concentration of 3DOM*([3DOM*]) relative to those from pristine seawaters,leading to higher photosensitizing effects on the photodegradation.Halide ions inhibit the DOM-sensitized photodegradation of UV-P by decreasing [3DOM*].Photodegradation half-lives of UV-P are estimated to range from 24.38 to 49.66 hr in field water bodies of the Yellow River estuary.These results are of importance for assessing environmental fate and risk UV-P in coastal water bodies.展开更多
Photodegradation of Norfloxacin in aqueous solution containing algae under a medium pressure mercury lamp （15 W, λmax -365nm） was investigated. Results indicated that the photodegradation of Norfloxacin could be in...Photodegradation of Norfloxacin in aqueous solution containing algae under a medium pressure mercury lamp （15 W, λmax -365nm） was investigated. Results indicated that the photodegradation of Norfloxacin could be induced by the algae in the heterogeneous algaewater systems. The photodegradation rate of Norfloxacin increased with increasing algae concentration, and was greatly influenced by the temperature and pH of solution. Meanwhile, the cooperation action of algae and Fe（III）, and the ultrasound were beneficial to photodegradation of Norfloxacin. The degradation kinetics of Norfloxacin was found to follow the pseudo zero-order reaction in the suspension of algae. In addition, we discussed the photodegradation mechanism of Norfloxacin in the suspension of algae. This work will be helpful for understanding the photochemical degradation of antibiotics in aqueous environment in the presence of algae, for providing a new method to deal with antibiotics pollution.展开更多
In this study,a series of novel visible light driven n-CeO2/n-CdO heterojunction(CeO2/CdO)nanoco mposites we re successfully fabricated by simple ultrasonication method.Several characte rization tools including X-ray ...In this study,a series of novel visible light driven n-CeO2/n-CdO heterojunction(CeO2/CdO)nanoco mposites we re successfully fabricated by simple ultrasonication method.Several characte rization tools including X-ray diffraction(XRD),scanning electro n microscopy(SEM),transmission electron microscopy(TEM)and UV-vis diffuse reflectance spectroscopy(UV-DRS),etc.,were utilized to investigate the physicochemical properties of the catalyst and confirm the formation of heterojunction.Under visible light irradiations,the photocatalytic activities of the as-prepared CeO2/CdO nanocomposites were evaluated by degrading of Congo red(CR)and Rhodamine B(RhB)solutions.As a result,the CeO2/CdO(mass percentage ratio 1:3)nanocomposite displays remarkable performance for CR and RhB degradation.The enhancement in the photocatalytic performance of CeO2/CdO(1:3)nanocomposite can be attributed not only to the strong visible-light absorption region,separating the photogenerated electronhole pairs but also to the formation of n-n type heterojunction.The results also indicate that the CeO2/CdO(1:3)nanocomposite has good stabilization and high reusability.In addition,the mechanism is proposed for the coupled semiconductors and possible reasons for the enhancement of visible-light photocatalytic efficiency are also discussed.This work can provide a new gateway to fabricate visible photocatalysts and promising candidate catalysts for poisonous wastewater treatment in the near future.展开更多
To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows f...To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows first-order kinetics. The degradation intermediates were identified with gas chromatography-mass spectrometry. A plausible mechanism was discussed to explain the process. Several influences on degradation process were investigated and reported such as the effects of initial concentration of pyrethroids, total time of light irradiation, solvents, and light source, as well as the effect of a few substances that exist in the environment. This study could be a good reference for the degradation of pyrethroids in practical circumstances.展开更多
This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu（Ⅱ） alone could induce a photo Fenton-like reaction to enhance th...This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu（Ⅱ） alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical （.OH） was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu（Ⅱ）, the photodegradation was accelerated, in which singlet oxygen （102） replaced -OH acting as the prevailing species. A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.展开更多
Photodegradation of nonylphenol ethoxylates （NPloEO） was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate prod...Photodegradation of nonylphenol ethoxylates （NPloEO） was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate products including aldehydic compounds, carboxylic compounds and cyclohexanyl compounds were identified. Five main degradation routes involving the oxidation of the alkyl chain and ethoxylate unit, shortening of the alkyl chain and ethoxylate unit, hydrogenation of the benzene ring were proposed.展开更多
The sunlight photodegradation half-lives of 20 mg/L acetochlor were 151, 154 and 169 days in de-ionized water, river water and paddy water, respectively. When exposed to ultraviolet (UV) light, acetochlor in aqueous s...The sunlight photodegradation half-lives of 20 mg/L acetochlor were 151, 154 and 169 days in de-ionized water, river water and paddy water, respectively. When exposed to ultraviolet (UV) light, acetochlor in aqueous solution was rapidly degraded. The half-lives were 7.1, 10.1, and 11.5 min in de-ionized water, river water and paddy water, respectively. Photoproducts of acetochlor were identified by gas chromatography/mass spectrometry(GC/MS) and found at least twelve photoproducts resulted from dechlorination with subsequent hydroxylation and cyclization processes. The chemical structures of ten photoproducts were presumed on the basis of mass spectrum interpretation and literature data. Photoproducts are identified as 2-ethyl-6-methylaniline; N,N-diethylaniline; 4,8-dimethyl-2-oxo-1,2,3,4- tetrahydroquino-line; 2-oxo-N-(2-ethyl-6-methylphenyl)-N-(ethoxymethyl)acetamide; N-(ethoxymethyl)-2′-ethyl-6′-methylformanilide;1-hydroxyacetyl-2-ethoxyl-7-ethylind ole; 8-ethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 4,8-dimethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 2-hydroxy-2′-ethyl-6′-methyl-N-(ethoxymethyl)acetanilide and a compound related to acetochlor. The other two photoproducts were detected by GC/MS although their chemical structure was unknown.展开更多
基金supported by the Project of State Key Laboratory of Treatments and Recycling for Organic Effluents by the Adsorption in Petroleum and Chemical Industry,Soochow University(No.SDHY2207)the Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes,Ministry of Education,College of Environment,Hohai University(No.B230203006)A Project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Developing environmental-friendly non-metal photocatalysts for the efficient removal of antibiotics from environment is a significant challenge.The construction of heterojunction is regarded as a powerful strategy to enhance the photodegradation efficiency of photocatalysts for pollutants,being due that this strategy can effectively suppress the recombination of the photo-induced electron and hole.In this research,a novel double Z-scheme BN/C_(60)/g-C_(3)N_(4) heterojunction was successfully synthesized via one-step synthetic approach.Based on a series of experimental characterization,BN/C_(60)/g-C_(3)N_(4) is most likely formed via the interaction between N element of BN and g-C_(3)N_(4) with C_(60) under UV-light irradiation.The band structures of BN,C_(60),g-C_(3)N_(4) and the internal electric field among them suggest that BN/C_(60)/g-C_(3)N_(4) may has a direct double z-type band arrangement,which facilitates efficient charge transfer.The photodegradation rate of BN/C_(60)/g-C_(3)N_(4) for tetracycline reached 90.1%,which is 2.9 times higher than that observed with BN and 2.3 times higher than that of g-C_(3)N_(4).BN/C_(60)/g-C_(3)N_(4) exhibits remarkable photocatalytic performance across a wide pH range and in the influence of different anions.This study offers significant insights about how to design double z-scheme metal-free photocatalyst with high photodegradation efficiency for antibiotic.
基金the financial supports from the National Key Research and Development Program of China(Nos.2021YFB3500600,2021YFB3500605,2022YFB3504100)Key R&D Program of Jiangsu Province(No.BE2022142)+6 种基金Ministry of Education Chunhui plan international cooperation project(No.202200554)National Natural Science Foundation of China(No.grant 22208170)Natural Science Foundation of Inner Mongolia(No.2021BS02016)Jiangsu International Cooperation Project(No.BZ2021018)Nanjing Science and Technology Top Experts Gathering Plan,and Open Foundation of State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control(No.SEMPC2023004)Cooperation Foundation for the Chunhui Plan Program of Ministry of Education of China(No.202200554)Open Project Program of Key Laboratory of Opticelectric Sensing and Analytical Chemistry for Life Science(No.M2024-7),MOE。
文摘It has been challenging for Fe(Ⅲ)regeneration in Fe-based photocatalysts for continuous peroxydisulfate(PDS)activation due to the lower ability to reduce Fe(Ⅲ).In this work,Fe-doped ultrathin VO_(2)(Fe-VO_(2))nanobelts were synthesized for purifying metronidazole(MNZ)via PDS activation.As an efficient Fentonlike catalyst for PDS activation,2 wt%Fe-doped VO_(2)can remove 98%of MNZ within 40 min and exhibits impressive recyclability.The synergistic effect of Fe-VO_(2)and Fe(Ⅲ)activated PDS boosted the photocatalytic performance.Moreover,SO_(4)•^(−),h+,O_(2)•^(−),^(1)O_(2),and•OH were the main reactive radicals.The effects of initial MNZ concentration,Fe-VO_(2),PDS dosage,and various anions/cations on MNZ removal by the Fe-VO_(2)/PDS/Vis system were studied.The intermediates of MNZ degradation and possible pathways were determined by density function theory(DFT)calculations and HPLC-MS.This study provided a sustainable technology using Fe-doped ultrathin VO_(2)nanobelts for photocatalytic PDS activation and decontamination of pharmaceutical wastewater.
基金Funded by the National Natural Science Foundation of China(Nos.52102110 and 42272355)the China Postdoctoral Science Foundation(No.2023M732724)。
文摘Ti_(3)C_(2)/BiOCl composite was successfully synthesized by combining BiOCl(BOC)with an exposed(110)crystal plane and Ti_(3)C_(2) using a simple hydrothermal process.The photocatalytic performance of produced composite was evaluated using the degradation of rhodamine B(RhB)and tetracycline hydrochloride(TCH)under visible light.The results demonstrated that Ti_(3)C_(2)/BOC composite had higher photocatalytic activity than pure BOC.The optimum incorporation amount of Ti_(3)C_(2) was 2 wt%.The photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC at 10 min to 20 mg/L RhB was 97.6%,which was much higher than that of BOC(75.3%).Similarly,the photodegradation rate of 2 wt%-Ti_(3)C_(2)/BOC to 10 mg/L TCH at 30 min was 80.4%,which was higher than BOC(68.1%).In addition,the prepared 2 wt%-Ti_(3)C_(2)/BOC composite also maintained good stability even after four cycles.Electrochemical impedance spectroscopy(EIS),transient photocurrent response(IT)and ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)confirmed that the photoelectrochemical properties of 2 wt%-Ti_(3)C_(2)/BOC composite were significantly improved.On the basis of analyzing the action mechanism of photocatalyst,it was pointed out that·O_(2)^(-)and h~+were the main active substances in the photodegradation of RhB and TCH by 2 wt%-Ti_(3)C_(2)/BOC.
基金supported by the Natural Science Foundation of Shenzhen(No.GXWD20201230155427003-20200802110025006)the National Natural Science Foundation of China(Nos.52170157 and 52111530188)+3 种基金the Major Program of Jiangxi Provincial Depart-ment of Science and Technology(No.2022KSG01004)the Natural Science Foundation of Shenzhen(No.JCYJ20220531095408020)the Start-up Grant Harbin Institute of Technology(Shenzhen)(No.IA45001007)the Start-up Talent Grant at Harbin Institute of Technology(Shenzhen)(No.HA11409066).
文摘The edge-graphitized carbon nitride(C_(3)N_(4)-C g)was prepared by secondary pyrolysis to construct ZnO/C_(3)N_(4)-C g(ZCN)type-Ⅱheterojunction photocatalyst via a facile sonication dispersion method,which achieved∼7.04-fold and∼18.3-fold enhanced visible-light-driven photocatalytic performance for refrac-tory micropollutant removal and simultaneous hydrogen(H_(2))evolution respectively compared to con-ventional ZnO/g-C_(3)N_(4)Step-scheme heterojunction.The apparent quantum efficiency of the ZCN_(0.4)het-erojunction reaches 0.92%(λ=420 nm).Such excellent performance stems from that the edge-graphene moieties stitched onto the interface of heterojunction extend light absorption to the full visible spec-trum,meanwhile,the built-in electric field generated during Fermi level alignment accompanying fa-vorable band-bending structure provides an effective pathway for the rapid migration of photoinduced electrons via the edge graphene channel to improve interfacial charge separation efficiency.Interestingly,the midgap states introduced in ZCN heterojunction could temporarily retain photoexcited electrons to effectively inhibit the in situ carrier recombination for improved photocatalytic H_(2)evolution.Moreover,ZCN/peroxymonosulfate system exhibited excellent anti-interference performance against complex water bodies under visible illumination due to the synergistic effect between the co-existing anions and organic matter.Meanwhile,the eco-friendly nature of the ZCN/peroxymonosulfate system showed no biotoxicity of reaction filtrate on cell proliferation after treatment,which avoided secondary contamination.Consid-ering the outstanding performance in photocatalysis,the ZCN system exhibits broad potential for practical applications in water pollution control and green energy production.
文摘La,Ce co-doped ZnO nanorods(ZnLC)were synthesized through a one-step solvothermal route.The photocatalysts were characterized by X-ray diffraction,Raman spectroscopy,field-emission scanning electron microscopy,energy dispersive X-ray,transmission electron microscopy,UV-vis diffuse reflectance spectroscopy and photo luminescence spectroscopy.The La and Ce doping enhanced the visible light absorption ability of ZnLC and a red shift was detected for ZnLC.Under simulated solar light irradiation,the ZnO doped with 3 at%La and 1 at%Ce(ZnLC1)degrades methylene blue(MB)more effectively than those of pure ZnO,La-doped ZnO(ZnL)and commercially available ZnO.The improved photocatalytic performance of ZnLC1 can be attributed to the high charge separation efficiency as demonstrated by the photoluminescence spectra.Additionally,the photocatalytic experiments reveal that several parameters have their own impact on the MB degradation.Using a variety of radical scavengers,it is discovered that superoxide anion radical plays a crucial role in the degradation of MB.The ZnLC1 is also reused several times without noticeable decrease of photoactivity,indicating that it has a substantial potential for environmental remediation applications.
基金supported by the National Natural Science Foundation of China (Nos.42177354 and 21777032)the National Key R&D Program of China (No.2019YFC0214402)the Guangdong Basic and Applied Basic Research oundation (No.2019B151502064)。
文摘Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still unclear.Here,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light sources.Xe lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 min.The xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and carbonyls.Among them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of xylenes.Moreover,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure risk.Therefore,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded xylenes.The findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.
基金National Natural Science Foundation of China(Nos.51902282 and 12274361)Qinglan Project of Jiangsu of China,the Natural Science Foundation of Jiangsu Province(No.BK20211361)College Natural Science Research Project of Jiangsu Province(No.20KJA430004).
文摘Developing high-efficiency photocatalysts for tetracycline hydrochloride(TCH)degradation is of great sig-nificance to ecosystems and human beings.In this work,a two-step process of exfoliation and re-stacking was performed to prepare re-stacked HTiNbO_(5) nanosheets(R-HTNS)and then coupled with Ti_(3)C_(2) MXene to construct Ti_(3)C_(2) MXene/R-HTNS(MX/RTS)with a 2D/2D Schottky heterojunction.These 2D/2D het-erostructures between Ti_(3)C_(2) MXene and R-HTNS can produce an internal electric field and provide max-imum interface area for efficient charge transfer across the intimate interface.The photocatalytic perfor-mance of samples was evaluated by TCH degradation under simulated sunlight.The MX/RTS composites,with an optimal sample of 3-MX/RTS,show enhanced photocatalytic activity for TCH degradation com-pared with R-HTNS.The characterization results reveal that the introduction of Ti_(3)C_(2) MXene can signif-icantly increase specific surface area for providing more reactive sites and broaden the light absorption region.Besides,the incident light energy is absorbed by the Ti_(3)C_(2) MXene component in MX/RTS compos-ites to generate photothermal energy(heat),which facilitates the charge carrier separation and surface reaction kinetics.Thus,the enhanced TCH photodegradation activity for MX/RTS composites is due to the introduction of Ti_(3)C_(2) MXene,which possesses the synergistic effect of the increased specific surface area,improved light-harvesting capacity,2D/2D Schottky heterojunction,and photothermal energy effect.Additionally,the TCH photodegradation behavior is deliberated with a detailed discussion on various co-existing ions.During TCH photodegradation,the active radical species are determined for 3-MX/RTS.Ac-cording to the characterization results,the possible TCH photodegradation pathway and mechanism over 3-MX/RTS are explored.This work may offer a novel insight for constructing MXene-based heterostruc-tured photocatalysts with high efficiency.
基金supported by the Foundation of Science Re-search Program from the Hubei Provincial Department of Ed-ucation(No.Q20221711)the Program ofWuhan Research Center of Ecodyeing&Finishing and Functional Textile(No.EDFT2021002).
文摘Semiconductor heterojunction engineering and three-dimensional(3D)architecture con-struction have been considered highly desirable strategies to enhance photocatalytic perfor-mance.Herein,a BiOI/ZnO composite photocatalyst with a 3D flower-like architecture was successfully prepared,whichwas stably immobilized on three-dimensional porous lignocel-lulosic biomass Juncus effusus(JE)fiber.The outstanding photocatalytic performance of the BiOI/ZnO-JE fiber was confirmed by the degradation of tetracycline hydrochloride(TC,90%),ciprofloxacin(CIP,79%),and norfloxacin(NOR,81%).The enhanced photocatalytic activities were mainly attributed to the synergistic absorption performance of the lignocellulosic JE and the effective transfer and separation of charges.Moreover,the hydroxyl(·OH)and super-oxide radicals(·O_(2)^(−))are themain reactive species in the photocatalytic process according to the analysis.This work may provide a novel perspective for constructing high-performance lignocellulosic-based photocatalytic materials.
基金supported by the Project of the State Key Laboratory of Pollution Control and Resource Reuse Foundation,Nanjing University(No.PCRRF21012)。
文摘We investigated the influence mechanism of N-doping for dissolved black carbon(DBC)photodegradation of organic pollutants.The degradation performance of N-doped dissolved black carbon(NDBC)for tetracycline(TC)(71%)is better than that for methylene blue(MB)(28%)under irradiation.These levels are both better than DBC degradation performances for TC(68%)and MB(18%)under irradiation.Reactive species quenching experiments suggest that h and-O,are the main reactive species for NDBC photodegraded TC,while-OH and h*are the main reactive species for NDBC photodegraded MB.-OH is not observed during DBC photodegradation of MB.This is likely because N-doping increases valence-band(VB)energy from 1.55 eV in DBC to 2.04 eV in NDBC;the latter is strong enough to oxidize water to form-OH.Additionally,N-doping increases the DBC band gap of 2.29 to 2.62 eV in NDBC,resulting in a higher separation efficiency of photo-generated electrons-holes in NDBC than in DBC.AIl these factors give NDBC stronger photodegradation performance for TC and MB than DBC.High-performance liquid chromatography-mass spectrometry(HPLC-MS)characterization and toxicity evaluation with the quantitative structure-activity relationship(QSAR)method suggest that TC photodegradation intermediates produced by NDBC have less aromatic structure and are less toxic than those produced by DBC.We adopted a theoretical approach to clarify the relationship between the surface groups of NDBC and the photoactive species produced.Our results add to the understanding of the photochemical behavior of NDBC.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.21901018,21971024,22271021)the Natural Science Foundation and Education Department of Liaoning province(Nos.2022-MS-373,2021-MS-312,LJ2020008).
文摘The widespread application of phenolic substances in the field of food,medicine and industry,is harmful to the environment and human health.Therefore,it is very important to develop a con-venient and effective method to detect and degrade phenolic compounds.Herein,we report a new keggin-type polyoxometallate-based metal-organic complex self-assembled under solvothermal condition,{[Cu(dap)(3-PA)]4(SiW_(12)O_(40))(H_(2)O)_(2)}·2H_(2)O(1,dap=1,2-diaminopropane,3-HPA=3-pyridineacrylic acid).1 shows an interesting 1D ladder-like structure.As a bifunctional catalyst,1 can be employed as a colori-metric sensor toward phenol with the relatively low detection limit(LOD)of 0.36μmol/L(S/N=3)in the wide range(0.001-0.1 mmol/L).The title colorimetric sensor is applied to determine phenol in various water environment with good recoveries ranging from 95%-105%.In addition,1 also exhibits excellent photocatalytic degradation toward phenol under visible light with the highest removal efficiency at 96%for 100 min and wide pH universality.The selectivity,stability and reliability of the detection of 1 towards phenol,as well as the detection for 4-chlorophenol,o-cresol,4-nitrophenol and phloroglucinol were stud-ied.Furthermore,the photocatalytic reaction kinetics and the mechanisms of photodegradation of phenol were also investigated in detail.
基金Project(1254G024)supported by the Young Core Instructor Foundation from Heilongjiang Educational Committee,ChinaProject(2012RFQXS113)supported by Scientific and Technological Innovation Talents of Harbin,China
文摘Both Ti foil and porous Ti were anodized in 0.5%HF and in ethylene glycol electrolyte containing 0.5%NH4F(mass fraction) separately. The results show that TiO2 nanotubes can be formed on Ti foil by both processes, whereas TiO2 nanotubes can be formed on porous Ti only in the second process. The overhigh current density led to the failure of the formation nanotubes on porous Ti in 0.5%HF electrolyte. TiO2 nanotubes were characterized by SEM and XRD. TiO2 nanotubes on porous Ti were thinner than those on Ti foil. Anatase was formed when TiO2 nanotubes were annealed at 400 °C and fully turned into rutile at 700 °C. To obtain good photodegradation, the optimal heat treatment temperature of TiO2 nanotubes was 450 °C. The porosity of the substrates influenced photodegradation properties. TiO2 nanotubes on porous Ti with 60% porosity had the best photodegradation.
基金supported by the National Natural Science Foundation of China(2137312021471022)+5 种基金the Development of Science and Technology Plan of Jilin ProvinceChina(2010154920130102001JC)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT13022)of Chinathe Program of Jilin Provincial Education Department(20131302013146)~~
文摘Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity of the composites were evaluated by their ability to photodegrade methylene blue and dimethyl phthalate（DMP） under visible-light irradiation. Compared with pure V2O5 and MoO 3,the V2O5/MoO 3 composites showed enhanced visible-light photocatalytic activity because of a V 3d impurity energy level and the formation of heterostructures at the interface between V2O5 and MoO 3. The optimal molar ratio of V to Mo in the V2O5/MoO 3 composites was found to be around 1/2. Furthermore,high-performance liquid chromatographic monitoring revealed that phthalic acid was the main intermediate in the photocatalytic degradation process of DMP.
基金supported by the National Basic Research Program (973) of China (No. 2010CB429003)the National Natural Science Foundation of China (No.21077010)the Fok Ying-Tong Education Foundation,China (No. 121077)
文摘To advance the knowledge of the environmental fate of sulfamethoxazole （SMX）, we systematically investigated the effects of natural water constituents and synthetic substances （i.e., TiO2 nanoparticles （nTiO2） and Ti-doped ^-Bi203 （NTB）） on the photodegradation kinetics of SMX under xenon lamp irradiation. The photolysis of SMX in aqueous solution followed first-order kinetics. Our results showed that higher concentrations of SMX, fulvic acid, suspended sediments, NTB and higher pH value decreased the photodegradation rates of SMX, whereas H202 improved the SMX photodegradation. TiO2 nanoparticles had a dual effect on pbotodegradation due to their photocatalytic activity and photoabsorption of photons. No intermediates more toxic toward Vibrio fischeri than SMX were produced after direct photolysis and photocatalytic degradation for 3 hr. The photolysis of SMX involved three pathways： hydroxylation, cleavage of the sulfonamide bond, and fragmentation of the isoxazole ring. This study lays the groundwork for a better understanding of the environmental fate of SMX.
基金supported by the National Key R&D Program of China(No.2018YFC1801604)the National Natural Science Foundation of China(No.21661142001)
文摘Benzotriazole UV stabilizers (BT-UVs) have attracted concems due to their ubiquitous occurrence in the aquatic environment,and their bioaccumulative and toxic properties.However,little is known about their aquatic environmental degradation behavior.In this study,photodegradation of a representative of BT-UVs,2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P),was investigated under simulated sunlight irradiation.Results show that UV-P photodegrades slower under neutral conditions (neutral form) than under acidic or alkaline conditions (cationic and anionic forms).Indirect photodegradation is a dominant elimination pathway of UV-P in coastal seawaters.Dissolved organic matter (DOM) from seawaters accelerate the photodegradation rates mainly through excited triplet DOM (3DOM*),and the roles of singlet oxygen and hydroxyl radical are negligible in the matrixes.DOM from seawaters impacted by mariculture exhibits higher steady-state concentration of 3DOM*([3DOM*]) relative to those from pristine seawaters,leading to higher photosensitizing effects on the photodegradation.Halide ions inhibit the DOM-sensitized photodegradation of UV-P by decreasing [3DOM*].Photodegradation half-lives of UV-P are estimated to range from 24.38 to 49.66 hr in field water bodies of the Yellow River estuary.These results are of importance for assessing environmental fate and risk UV-P in coastal water bodies.
基金supported by A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) (No. 1105007001)
文摘Photodegradation of Norfloxacin in aqueous solution containing algae under a medium pressure mercury lamp （15 W, λmax -365nm） was investigated. Results indicated that the photodegradation of Norfloxacin could be induced by the algae in the heterogeneous algaewater systems. The photodegradation rate of Norfloxacin increased with increasing algae concentration, and was greatly influenced by the temperature and pH of solution. Meanwhile, the cooperation action of algae and Fe（III）, and the ultrasound were beneficial to photodegradation of Norfloxacin. The degradation kinetics of Norfloxacin was found to follow the pseudo zero-order reaction in the suspension of algae. In addition, we discussed the photodegradation mechanism of Norfloxacin in the suspension of algae. This work will be helpful for understanding the photochemical degradation of antibiotics in aqueous environment in the presence of algae, for providing a new method to deal with antibiotics pollution.
文摘In this study,a series of novel visible light driven n-CeO2/n-CdO heterojunction(CeO2/CdO)nanoco mposites we re successfully fabricated by simple ultrasonication method.Several characte rization tools including X-ray diffraction(XRD),scanning electro n microscopy(SEM),transmission electron microscopy(TEM)and UV-vis diffuse reflectance spectroscopy(UV-DRS),etc.,were utilized to investigate the physicochemical properties of the catalyst and confirm the formation of heterojunction.Under visible light irradiations,the photocatalytic activities of the as-prepared CeO2/CdO nanocomposites were evaluated by degrading of Congo red(CR)and Rhodamine B(RhB)solutions.As a result,the CeO2/CdO(mass percentage ratio 1:3)nanocomposite displays remarkable performance for CR and RhB degradation.The enhancement in the photocatalytic performance of CeO2/CdO(1:3)nanocomposite can be attributed not only to the strong visible-light absorption region,separating the photogenerated electronhole pairs but also to the formation of n-n type heterojunction.The results also indicate that the CeO2/CdO(1:3)nanocomposite has good stabilization and high reusability.In addition,the mechanism is proposed for the coupled semiconductors and possible reasons for the enhancement of visible-light photocatalytic efficiency are also discussed.This work can provide a new gateway to fabricate visible photocatalysts and promising candidate catalysts for poisonous wastewater treatment in the near future.
基金supported by the State Key Laboratory of Environmental Chemistry and Ecotoxicology of China(No. KF2008-08)the Education Department of Hebei(No. ZH200805)
文摘To understand the degradation and environmental fate of pyrethroids, the process of their photodegradation under simulated natural conditions was investigated. The results showed that the degradation process follows first-order kinetics. The degradation intermediates were identified with gas chromatography-mass spectrometry. A plausible mechanism was discussed to explain the process. Several influences on degradation process were investigated and reported such as the effects of initial concentration of pyrethroids, total time of light irradiation, solvents, and light source, as well as the effect of a few substances that exist in the environment. This study could be a good reference for the degradation of pyrethroids in practical circumstances.
基金supported by the National Basic Research Program (973) of China (No. 2007CB407302)the New Century Excellent Talent Program of the Ministry of Education of China (2010)the Fundamental Research Funds for the Central Universities of China (No.DUT11ZD108)
文摘This work was designed to explore the characteristics of photodegradation of herbicides in the copper-polluted water body. The results showed that Cu（Ⅱ） alone could induce a photo Fenton-like reaction to enhance the degradation of atrazine, in which hydroxyl radical （.OH） was a main active species. Humic acids restrained atrazine degradation, nevertheless, when introducing Cu（Ⅱ）, the photodegradation was accelerated, in which singlet oxygen （102） replaced -OH acting as the prevailing species. A feasible mechanism for the photochemical process was also proposed, which is helpful for better understanding the environmental photochemistry of atrazine in the copper-polluted water.
文摘Photodegradation of nonylphenol ethoxylates （NPloEO） was investigated in laboratory scale under UV irradiation. The intermediate photodegradation products were analyzed by LC-ESI-MS. Three kinds of intermediate products including aldehydic compounds, carboxylic compounds and cyclohexanyl compounds were identified. Five main degradation routes involving the oxidation of the alkyl chain and ethoxylate unit, shortening of the alkyl chain and ethoxylate unit, hydrogenation of the benzene ring were proposed.
文摘The sunlight photodegradation half-lives of 20 mg/L acetochlor were 151, 154 and 169 days in de-ionized water, river water and paddy water, respectively. When exposed to ultraviolet (UV) light, acetochlor in aqueous solution was rapidly degraded. The half-lives were 7.1, 10.1, and 11.5 min in de-ionized water, river water and paddy water, respectively. Photoproducts of acetochlor were identified by gas chromatography/mass spectrometry(GC/MS) and found at least twelve photoproducts resulted from dechlorination with subsequent hydroxylation and cyclization processes. The chemical structures of ten photoproducts were presumed on the basis of mass spectrum interpretation and literature data. Photoproducts are identified as 2-ethyl-6-methylaniline; N,N-diethylaniline; 4,8-dimethyl-2-oxo-1,2,3,4- tetrahydroquino-line; 2-oxo-N-(2-ethyl-6-methylphenyl)-N-(ethoxymethyl)acetamide; N-(ethoxymethyl)-2′-ethyl-6′-methylformanilide;1-hydroxyacetyl-2-ethoxyl-7-ethylind ole; 8-ethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 4,8-dimethyl-1-ethoxymethyl-2-oxo-1,2,3,4-tetrahydroquinoline; 2-hydroxy-2′-ethyl-6′-methyl-N-(ethoxymethyl)acetanilide and a compound related to acetochlor. The other two photoproducts were detected by GC/MS although their chemical structure was unknown.
