The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemica...The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemical composition of Fe_(3)O_(4) crystals was achieved under the microwave shock method with the same effect as that of calcination treatment.Fe_(3)O_(4) catalyst for the removal of the dye Rhodamine B (Rh B) from polluted wastewater under microwave (MW),H_(2)O_(2) system.The results showed that Fe_(3)O_(4) nanomicrospheres prepared by microwave shock exhibited superior catalytic activity under the conditions of 500 W,0.4 mol/L H_(2)O_(2) and10 mg/L Rh B,and the removal rate of Rh B reached 98.5%after 10 min.The Fe_(3)O_(4) catalysts also exhibited good stability and degradation efficiency.Electron paramagnetic resonance experiments confirmed that·OH plays a major role in the rapid degradation of Rh B.Under microwave action,the catalyst produces electron-hole pairs,in which the holes react with OH-produced by water ionisation to form·OH,and the microwave-treated Fe_(3)O_(4) produces more active species.Fe^(3+)and Fe^(2+)serve as microwave catalytic activity centers and Fenton catalytic activity centers,respectively.This research demonstrates that optimizing the Fe^(2+)/Fe^(3+) ratio significantly enhances the degradation efficiency of Rh B.This study presents novel views regarding the mechanism of microwave synergistic catalyst-induced Fenton.展开更多
A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform inf...A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FIIR)spectra,scanning electron microscope(SEM),X-ray photoelectron spectra(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).The SEM analyses indicate that the introduction of CS promotes the formation of a unique flower-like structure in BiOBr,which not only optimizes the efficiency of light capture but also increases the specific surface area of BiOBr.The bandgap of the composite was narrower compared with the pure BiOBr.The CS/BiOBr composites exhibited higher photocatalytic activity than pure CS and BiOBr under visible light irradiation,and a higher first-order reaction rate constant(k)of 0.0437 min-1 than BiOBr(0.0146 min^(-1)),and exhibited excellent stability and reusability during the cyclic run.The enhanced photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes.Superoxide radicals and holes were the major active species.展开更多
Zirconia nanotube array films(ZNAF)prepared by anodic oxidation method were used as immobilization materials for acridine orange(AO),rhodamine B(RB)and AO-RB systems.A comparative study on their fluorescence emission ...Zirconia nanotube array films(ZNAF)prepared by anodic oxidation method were used as immobilization materials for acridine orange(AO),rhodamine B(RB)and AO-RB systems.A comparative study on their fluorescence emission intensity,fluorescence resonance energy transfer(FRET)and fluorescence detection of nitrite in aqueous solutions and on immobilization films with ZNAF as carriers was carried out.Results demonstrate that the solution pH values and immobilization on ZNAF have a great influence on the per-formance of these fluorescent molecules.Compared with aqueous solutions,the fluorescence emission in-tensity of AO and RB is considerably increased by immobilization,which is 8.0 and 4.2 times higher than the original,respectively.The energy transfer efficiency(E)of the AO-RB system increases from 40.9%to 84.8%by loading it on ZNAF.Moreover,after immobilization onto ZNAF,the fluorescence detection performance of nitrite is also significantly improved.The limit of detection decreases from 0.95 ng/mL to 0.22 ng/mL and the sensitivity increases from 939.18 to 15,031.68 mL/μg through loading AO onto ZNAF.展开更多
Up to now,“Turn-on”fluorescence sensor exhibits promising potential toward the detection of heavy metal ions,anions,drugs,organic dyes,DNA,pesticides,and other amino acids due to their simple,quick detection,and hig...Up to now,“Turn-on”fluorescence sensor exhibits promising potential toward the detection of heavy metal ions,anions,drugs,organic dyes,DNA,pesticides,and other amino acids due to their simple,quick detection,and high sensitivity and selectivity.Herein,a novel fluorescence method of detecting Cr^(3+)in an aqueous solution was described based on the fluorescence resonance energy transfer between rhodamine B(Rh B)and gold nanoparticles(Au NPs).The fluorescence of Rh B solution could be obviously quenched(“off”state)with the presence of citrate-stabilized Au NPs.However,upon addition of Cr^(3+)to Au NPs@Rh B system,the fluorescence of Au NPs was recovered owing to the strong interaction between Cr^(3+)and the specific groups on the surface of citrate-stabilized Au NPs,which will lead to the aggregation of Au NPs(“on”state).At this point,the color of the reaction solution turned to black.Under optimal conditions,the limit of detection(LOD)for Cr^(3+)was 0.95 n M(signal-to-noise ratio,S/N=3)with a linear range of 0.164 n M to 3.270μM.Furthermore,the proposed method exhibits excellent performances,such as rapid analysis,high sensitivity,extraordinary selectivity,easy preparation,switch-on fluorescence response,and non-time consuming.展开更多
Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction ...Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction is constructed by hybridizing a 3D flower like Schiff-based covalent organic framework(COF)with a porous structure g-C_(3)N_(4),and a comprehensive strategy is proposed to achieve efficient H_(2)O_(2)pro-duction yield coupling highly Rhodamine B(RhB)degradation rate.The charge carrier transfer mechanism is validated by an in-situ X-ray photoelectron spectroscopy,the density functional theory calculation,and a femtosecond transient absorption spectroscopy.Interestingly,the COF/g-C_(3)N_(4)S-scheme heterojunction exhibits better charge separation efficiency compared to bare COF and pure g-C_(3)N_(4),resulting in ameliora-tive photocatalytic activity.In addition,RhB is employed to consume photogenerated holes.Remarkably,2307μmol g^(-1)h^(-1)H_(2)O_(2)achieved over 10%-COF/g-C_(3)N_(4)composite in RhB solution and O_(2)atmosphere,and 100%-RhB degradation rate obtained at 45 min.This work improves a facile strategy to ameliorate SchiffCOF-based S-scheme heterojunction for efficient H_(2)O_(2)production with full hole-electron utilization ability.展开更多
A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,high-resolution ...A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,high-resolution transmission electron microscopy（HRTEM）,X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal（h-WO3） and monoclinic（m-WO3） crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase（m-WO3）/hexagonal phase（h-WO3） junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.展开更多
Rhodamine is one class of most popular dyes used in fluorescence imaging due to the outstanding photoproperties including high brightness and photostability. In recent years, replacement the xanthene oxygen with other...Rhodamine is one class of most popular dyes used in fluorescence imaging due to the outstanding photoproperties including high brightness and photostability. In recent years, replacement the xanthene oxygen with other elements, especially silicon, has attracted great attentions in the development of new rhodamine derivatives. This review summarized the structures and photophysical properties of heteroatom-substituted rhodamines. We hope this review can help to understand the structure-property relationships of rhodamine dyes and then elucidate the way to create derivatives with improved photoproperties.展开更多
Polarization variable-angle synchronous fluorescence spectrometry was proposed to determine samples in turbid solution. A mixture of fluorescein, rhodamine 6G and rhodamine B was used to evaluate the technique. The ba...Polarization variable-angle synchronous fluorescence spectrometry was proposed to determine samples in turbid solution. A mixture of fluorescein, rhodamine 6G and rhodamine B was used to evaluate the technique. The background caused by scattering light was decreased remarkably. The limits of detection were 0.6 ng/ml for fluorescein, 2.3 ng/ml for rhodamine 6G and 4.1 ng/ml for rhodamine B, respectively.展开更多
In acid medium, rhodamine B（RhB）, rhodamine S（RhS）, rhodamine 6G（RhG） and butyl rhodamine B（b-RhB） have a fluorescence peak at 580, 549, 553 and 580nm, respectively. BrO^-3 oxidizes excess I^- into I^-3 Rhodam...In acid medium, rhodamine B（RhB）, rhodamine S（RhS）, rhodamine 6G（RhG） and butyl rhodamine B（b-RhB） have a fluorescence peak at 580, 549, 553 and 580nm, respectively. BrO^-3 oxidizes excess I^- into I^-3 Rhodamine dyes combine I^-3 to form ion association nanoparticles, resulting in fluorescence quenching at 580, 549, 553 and 580 rim, respectively. The fluorescence quenching intensity is proportional to the concentration of BrO^-3 in the range of 0.020 4 - 0.710 μg/mL for RhB, 0.025 - 0. 512μg/mL for RhS, 0.025 - 0.260 μg/mL for RhG, 0.025 - 1.28μg/mL for b-RhB, respectively. In the four systems, RhB system has good stability and high sensitivity. Thus, a simple, sensitive fluorescence method was proposed for the determination of BrO^-3 in commercial bread additives and flours, with satisfactory results. The results of the fluorescence spectra and scan electron microscopy show that the formation of about 60 ran （RhB - I^-3） n association nanoparticles and the interface between the nanoparticles and solution are main factors that cause the fluorescence quenching.展开更多
We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rathe...We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.展开更多
The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray...The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM)and Brunauer-Emmett-Teller(BET).In the process of microwave-enhanced photocatalysis(MPC),RhB(30 mg/L)was almost completely decoloured in 10 min,and the mineralization efficiency was 96.0%in 20 min.The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25.Additionally,according to gas chromatography/mass spectrometry(GC/MS)and liquid chromatography/mass spectrometry(LC/MS)identification,the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates(N,N-diethyl-N'-ethyl-rhodamine(DER)),oxalic acid,malonic acid,snccinic acid,and phthalic acid,maleic acid,3-nitrobenzoic acid,and so on.The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure,and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.展开更多
Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate...Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char （APTC） for Rhodamine B （RhB）. Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.展开更多
A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffracti...A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD)results showed that the PbO2 coating was composed of anα-PbO2 inner layer and aβ-PbO2 outer layer.Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h.Rhodamine B(RhB)was employed as a model pollutant to analyze the electrocatalytic activity of the electrode.The effects of initial RhB concentration,current density,initial pH,temperature,and chloride ion concentration on the electrochemical oxidation were investigated in detail.Inductively coupled plasma atomic emission spectroscopy(ICP-AES)results suggested that the concentration of leached Pb^2+in the electrolyte during the electrocatalytic oxidation process can be neglected.Finally,the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC-MS).The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution.展开更多
Two novel rhodamine-based fluorescence enhanced molecular probes （RA1 and RA2） were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2＋. The recog...Two novel rhodamine-based fluorescence enhanced molecular probes （RA1 and RA2） were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2＋. The recognizing behaviors were investigated both experimentally and computationally. They exhibited high selectivity and sensitivity for Hg^2＋ over other commonly coexistent metal ions in CH3CN/H2O （1：1, V/V） solution. Test shows that hydroxy benzene of rich electron was beneficial to the chelate of Hg^2＋ with sensors. The detection limit was measured to be at least 0.14 p.mol/L. After addition of Hg^2＋, the color changed from colourless to pink, which was easily and hydrogel sensor. detected by the naked eye in both solution展开更多
Microporous titanium dioxide films were prepared by the sol-gel methods on glass substrates, using tetrabutyl titanate as source material. In order to absorb the visible light and increase the photocatalytic activitie...Microporous titanium dioxide films were prepared by the sol-gel methods on glass substrates, using tetrabutyl titanate as source material. In order to absorb the visible light and increase the photocatalytic activities, different concentrations of neodymium ions (Nd/Ti molar ratio was 0.5%, 0.7%, 0.9%, and 1.1% respectively) were added into the sol. X-ray diffraction (XRD), X-ray photoelectron spectros-copy (XPS), and atom force microscopy (AFM) were applied to characterize the modified films. A kind of typical textile industry pollutant (Rhodamine B) was used to evaluate the photocatalytic activities of the films under visible light. The results showed that the activities of the films were improved by doping Nd ions into the sol.展开更多
基金supported by Beijing Natural Science Foundation(No.2232062)the Fundamental Research Funds for the Central Universities (No.2652022006)。
文摘The Fenton method is an effective technology for the removal of organic materials from wastewater.In this work,an induced catalyst Fe_(3)O_(4) was synthesized by a hydrothermal method,and the modulation of the chemical composition of Fe_(3)O_(4) crystals was achieved under the microwave shock method with the same effect as that of calcination treatment.Fe_(3)O_(4) catalyst for the removal of the dye Rhodamine B (Rh B) from polluted wastewater under microwave (MW),H_(2)O_(2) system.The results showed that Fe_(3)O_(4) nanomicrospheres prepared by microwave shock exhibited superior catalytic activity under the conditions of 500 W,0.4 mol/L H_(2)O_(2) and10 mg/L Rh B,and the removal rate of Rh B reached 98.5%after 10 min.The Fe_(3)O_(4) catalysts also exhibited good stability and degradation efficiency.Electron paramagnetic resonance experiments confirmed that·OH plays a major role in the rapid degradation of Rh B.Under microwave action,the catalyst produces electron-hole pairs,in which the holes react with OH-produced by water ionisation to form·OH,and the microwave-treated Fe_(3)O_(4) produces more active species.Fe^(3+)and Fe^(2+)serve as microwave catalytic activity centers and Fenton catalytic activity centers,respectively.This research demonstrates that optimizing the Fe^(2+)/Fe^(3+) ratio significantly enhances the degradation efficiency of Rh B.This study presents novel views regarding the mechanism of microwave synergistic catalyst-induced Fenton.
文摘A flower-like BiOBr photocatalyst(CS/BiOBr)was prepared by using the carbon material derived from corn straw(CS)as the carrier.The prepared composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FIIR)spectra,scanning electron microscope(SEM),X-ray photoelectron spectra(XPS),and UV-Vis diffuse reflectance spectra(UV-Vis DRS).The SEM analyses indicate that the introduction of CS promotes the formation of a unique flower-like structure in BiOBr,which not only optimizes the efficiency of light capture but also increases the specific surface area of BiOBr.The bandgap of the composite was narrower compared with the pure BiOBr.The CS/BiOBr composites exhibited higher photocatalytic activity than pure CS and BiOBr under visible light irradiation,and a higher first-order reaction rate constant(k)of 0.0437 min-1 than BiOBr(0.0146 min^(-1)),and exhibited excellent stability and reusability during the cyclic run.The enhanced photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes.Superoxide radicals and holes were the major active species.
基金supported by the National Natural Science Foundation of China(No.51972095).
文摘Zirconia nanotube array films(ZNAF)prepared by anodic oxidation method were used as immobilization materials for acridine orange(AO),rhodamine B(RB)and AO-RB systems.A comparative study on their fluorescence emission intensity,fluorescence resonance energy transfer(FRET)and fluorescence detection of nitrite in aqueous solutions and on immobilization films with ZNAF as carriers was carried out.Results demonstrate that the solution pH values and immobilization on ZNAF have a great influence on the per-formance of these fluorescent molecules.Compared with aqueous solutions,the fluorescence emission in-tensity of AO and RB is considerably increased by immobilization,which is 8.0 and 4.2 times higher than the original,respectively.The energy transfer efficiency(E)of the AO-RB system increases from 40.9%to 84.8%by loading it on ZNAF.Moreover,after immobilization onto ZNAF,the fluorescence detection performance of nitrite is also significantly improved.The limit of detection decreases from 0.95 ng/mL to 0.22 ng/mL and the sensitivity increases from 939.18 to 15,031.68 mL/μg through loading AO onto ZNAF.
基金supported by the Natural Science Foundation of Qinghai Province in China(No.2019-ZJ-944Q)the University-level Planning Project of Qinghai Minzu University of Qinghai Province in China(Nos.2022GH11 and 2022GH13)。
文摘Up to now,“Turn-on”fluorescence sensor exhibits promising potential toward the detection of heavy metal ions,anions,drugs,organic dyes,DNA,pesticides,and other amino acids due to their simple,quick detection,and high sensitivity and selectivity.Herein,a novel fluorescence method of detecting Cr^(3+)in an aqueous solution was described based on the fluorescence resonance energy transfer between rhodamine B(Rh B)and gold nanoparticles(Au NPs).The fluorescence of Rh B solution could be obviously quenched(“off”state)with the presence of citrate-stabilized Au NPs.However,upon addition of Cr^(3+)to Au NPs@Rh B system,the fluorescence of Au NPs was recovered owing to the strong interaction between Cr^(3+)and the specific groups on the surface of citrate-stabilized Au NPs,which will lead to the aggregation of Au NPs(“on”state).At this point,the color of the reaction solution turned to black.Under optimal conditions,the limit of detection(LOD)for Cr^(3+)was 0.95 n M(signal-to-noise ratio,S/N=3)with a linear range of 0.164 n M to 3.270μM.Furthermore,the proposed method exhibits excellent performances,such as rapid analysis,high sensitivity,extraordinary selectivity,easy preparation,switch-on fluorescence response,and non-time consuming.
基金supported by the National Natural Science Foundation of China(Nos.22409128,22378103,and 52202376)the China Postdoctoral Science Foundation(No.2022TQ0316).
文摘Cooperative coupling of photocatalytic hydrogen peroxide production with organic pollutants degradation has an expansive perspective in energy storage and environmental conservation.Herein,an S-scheme het-erojunction is constructed by hybridizing a 3D flower like Schiff-based covalent organic framework(COF)with a porous structure g-C_(3)N_(4),and a comprehensive strategy is proposed to achieve efficient H_(2)O_(2)pro-duction yield coupling highly Rhodamine B(RhB)degradation rate.The charge carrier transfer mechanism is validated by an in-situ X-ray photoelectron spectroscopy,the density functional theory calculation,and a femtosecond transient absorption spectroscopy.Interestingly,the COF/g-C_(3)N_(4)S-scheme heterojunction exhibits better charge separation efficiency compared to bare COF and pure g-C_(3)N_(4),resulting in ameliora-tive photocatalytic activity.In addition,RhB is employed to consume photogenerated holes.Remarkably,2307μmol g^(-1)h^(-1)H_(2)O_(2)achieved over 10%-COF/g-C_(3)N_(4)composite in RhB solution and O_(2)atmosphere,and 100%-RhB degradation rate obtained at 45 min.This work improves a facile strategy to ameliorate SchiffCOF-based S-scheme heterojunction for efficient H_(2)O_(2)production with full hole-electron utilization ability.
基金supported by the National Natural Science Foundation of China (21573101)the Liaoning Provincial Natural Science Foundation(2014020107)+2 种基金the Program for Liaoning Excellent Talents in University (LJQ2014041)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry ([2013]1792)the Opening Project of Key Laboratory of Photochemical Conversion and Optoelectronic Materials, TIPC, CAS,the Opening Project of State Key Laboratory of Catalysis, DICP, CAS (N-09-06)~~
文摘A series of WO3 samples with different crystalline phases were prepared by the thermal decomposition method from ammonium tungstate hydrate.X-ray diffraction（XRD）,scanning electron microscopy（SEM）,high-resolution transmission electron microscopy（HRTEM）,X-ray photoelectron spectroscopy,and N2 adsorption-desorption were used to characterize the crystalline phase,morphology,particle size,chemical composition,and surface area of the WO3 samples.The formation of hexagonal（h-WO3） and monoclinic（m-WO3） crystal structures of WO3 at different temperatures or different times was confirmed by XRD.m-WO3 is formed at 600 ℃,while m-WO3 starts to transform into h-WO3 at 800℃.However,h-WO3,which forms at 800℃,may transform into m-WO3 by increasing the calcination temperature to 1000℃.SEM results indicate that m-WO3 particles exhibit a bulky shape with heavy aggregates,while h-WO3 particles exhibit a rod-like shape.Moreover,m-WO3 crystals are sporadically patched on the surface of the h-WO3 rod-like particles,resulting in the exposure of both m-WO3 and h-WO3 on the surface.It is observed that the monoclinic phase（m-WO3）/hexagonal phase（h-WO3） junction was fabricated by tuning the calcination temperature and calcination time.The relative ratios between m-WO3 and h-WO3 in the phase junction can readily be tailored by control of the calcination time.The photocatalytic activities of WO3 with different crystalline phases were evaluated by the photocatalytic degradation of rhodamine B as a model pollutant.A higher photocatalytic activity was observed in the WO3 sample with the m-WO3/h-WO3junction as compared with the sample with only m-WO3.The improvement of photocatalytic activity can be attributed to the reduction of the electron-hole recombination rate owing to the formation of the phase junction,whose presence has been confirmed by HRTEM and photoluminescence spectra.
基金financially supported by the National Natural Science Foundation China (No. 21878286)DICP (Nos. DMTO201603, TMSR201601)
文摘Rhodamine is one class of most popular dyes used in fluorescence imaging due to the outstanding photoproperties including high brightness and photostability. In recent years, replacement the xanthene oxygen with other elements, especially silicon, has attracted great attentions in the development of new rhodamine derivatives. This review summarized the structures and photophysical properties of heteroatom-substituted rhodamines. We hope this review can help to understand the structure-property relationships of rhodamine dyes and then elucidate the way to create derivatives with improved photoproperties.
文摘Polarization variable-angle synchronous fluorescence spectrometry was proposed to determine samples in turbid solution. A mixture of fluorescein, rhodamine 6G and rhodamine B was used to evaluate the technique. The background caused by scattering light was decreased remarkably. The limits of detection were 0.6 ng/ml for fluorescein, 2.3 ng/ml for rhodamine 6G and 4.1 ng/ml for rhodamine B, respectively.
基金supported by the National Natural Science Foundation of China(21003033,21203047)Guangxi Natural Science Foundation,China(2014GXNSFAA118019)+1 种基金Research Foundation of Education Bureau of Guangxi,China(ZD2014127)Doctor's Scientific Research Foundation of Hezhou University,China(HZUBS201401)~~
文摘In acid medium, rhodamine B（RhB）, rhodamine S（RhS）, rhodamine 6G（RhG） and butyl rhodamine B（b-RhB） have a fluorescence peak at 580, 549, 553 and 580nm, respectively. BrO^-3 oxidizes excess I^- into I^-3 Rhodamine dyes combine I^-3 to form ion association nanoparticles, resulting in fluorescence quenching at 580, 549, 553 and 580 rim, respectively. The fluorescence quenching intensity is proportional to the concentration of BrO^-3 in the range of 0.020 4 - 0.710 μg/mL for RhB, 0.025 - 0. 512μg/mL for RhS, 0.025 - 0.260 μg/mL for RhG, 0.025 - 1.28μg/mL for b-RhB, respectively. In the four systems, RhB system has good stability and high sensitivity. Thus, a simple, sensitive fluorescence method was proposed for the determination of BrO^-3 in commercial bread additives and flours, with satisfactory results. The results of the fluorescence spectra and scan electron microscopy show that the formation of about 60 ran （RhB - I^-3） n association nanoparticles and the interface between the nanoparticles and solution are main factors that cause the fluorescence quenching.
基金This work was supported by the National Basic Research Program of China （No.2010CB923300）, the National Natural Science Foundation of China （No.91127042 and No.21173205）, the Chinese Academy of Sciences （No.XDB01020000）, the FR- FCUC （No.WK2340000012）, the USTC-NSRL Joint Funds （No.KY2340000021）, and the National Under- graduate Innovative Training Program of Ministry of Education （No.201210358064）.
文摘We investigate the fluorescence quenching of Rhodamine 6G （R6G）, a well known laser dye with a high fluorescence quantum yield, by as-synthesized graphene oxide （GO） in aqueous solution, which is found to be rather efficient. By means of steady-state and time-resolved fluorescence spectroscopy combined with detailed analysis about the linear absorption vari- ation for this R6G-GO system, the pertinent quenching mechanism has been elucidated to be a combination of dynamic and static quenching. Possible ground-state complexes be- tween R6G and GO during the static quenching have also been suggested. Furthermore, the direction of photoindueed electron transfer between R6G and GO has been discussed.
基金supported by the National Natural Science Foundation of China(No.20707009)the Jiangsu Province Social Development Foundation(No.BS2007051)+1 种基金the Opening Foundation(WTWER0713)of Engineering Research Center for Water Treatment and Water Remediation of the Ministry of Education of Chinathe State Key Laboratory of Pollution Control and Resource Reuse Opening Foundation(No.PCRRCF07003).
文摘The photocatalytic degradation of Rhodamine B(RhB)was carried out using TiO_(2)supported on activated carbon(TiO_(2)-AC)under microwave irradiation.Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction(XRD),transmission electron microscopy(TEM)and Brunauer-Emmett-Teller(BET).In the process of microwave-enhanced photocatalysis(MPC),RhB(30 mg/L)was almost completely decoloured in 10 min,and the mineralization efficiency was 96.0%in 20 min.The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25.Additionally,according to gas chromatography/mass spectrometry(GC/MS)and liquid chromatography/mass spectrometry(LC/MS)identification,the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates(N,N-diethyl-N'-ethyl-rhodamine(DER)),oxalic acid,malonic acid,snccinic acid,and phthalic acid,maleic acid,3-nitrobenzoic acid,and so on.The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure,and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.
基金supported by the National Key Technologies R & D Program of China (No. 2006BAC02A12)the Key Technologies R & D Program of Tianjin, China (No.07ZCGYSH02000)the Natural Science Foundationof Tianjin, China (No. 08JCZDJC21400).
文摘Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char （APTC） for Rhodamine B （RhB）. Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little effect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.
基金supported by the National Natural Science Foundation of China(21507104)Natural Science Basic Research Plan in Shaanxi Province of China(2017JM2015)~~
文摘A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD)results showed that the PbO2 coating was composed of anα-PbO2 inner layer and aβ-PbO2 outer layer.Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h.Rhodamine B(RhB)was employed as a model pollutant to analyze the electrocatalytic activity of the electrode.The effects of initial RhB concentration,current density,initial pH,temperature,and chloride ion concentration on the electrochemical oxidation were investigated in detail.Inductively coupled plasma atomic emission spectroscopy(ICP-AES)results suggested that the concentration of leached Pb^2+in the electrolyte during the electrocatalytic oxidation process can be neglected.Finally,the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC-MS).The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution.
文摘Two novel rhodamine-based fluorescence enhanced molecular probes （RA1 and RA2） were synthesized, which were both designed as comparative fiuoroionophore and chromophore for the optical detection of Hg^2＋. The recognizing behaviors were investigated both experimentally and computationally. They exhibited high selectivity and sensitivity for Hg^2＋ over other commonly coexistent metal ions in CH3CN/H2O （1：1, V/V） solution. Test shows that hydroxy benzene of rich electron was beneficial to the chelate of Hg^2＋ with sensors. The detection limit was measured to be at least 0.14 p.mol/L. After addition of Hg^2＋, the color changed from colourless to pink, which was easily and hydrogel sensor. detected by the naked eye in both solution
基金Project supported by the State Key Laboratory of Urban Water Resource and Environment (HIT 08UWQA05) and National Key Laboratory of Vacuum and Cryogenics Technology and Physics (9140C550201060C55)
文摘Microporous titanium dioxide films were prepared by the sol-gel methods on glass substrates, using tetrabutyl titanate as source material. In order to absorb the visible light and increase the photocatalytic activities, different concentrations of neodymium ions (Nd/Ti molar ratio was 0.5%, 0.7%, 0.9%, and 1.1% respectively) were added into the sol. X-ray diffraction (XRD), X-ray photoelectron spectros-copy (XPS), and atom force microscopy (AFM) were applied to characterize the modified films. A kind of typical textile industry pollutant (Rhodamine B) was used to evaluate the photocatalytic activities of the films under visible light. The results showed that the activities of the films were improved by doping Nd ions into the sol.
