The photocatalytic degradation of dye pollutant sulforhodamine-B (SRB) in aqueous titanium dioxide (TiO2) dispersions was examined under three lighting regimes: UV light (330 nm〈λ〈 380 nm), sunlight, and vis...The photocatalytic degradation of dye pollutant sulforhodamine-B (SRB) in aqueous titanium dioxide (TiO2) dispersions was examined under three lighting regimes: UV light (330 nm〈λ〈 380 nm), sunlight, and visible light (λ〉450 nm), all investigated at pH=2.5. Total organic carbon (TOC) and chemical oxygen demand (CODer) assays show that the degradation rate of SRB is much higher when irradiated with UV and sunlight compared with visible light. The temporal concentration changes of SRB illustrated a first-order reaction and the rate constant, k, is 0.197 min^-1, 0.152 min^-1, 0.027 min^-1, respectively, under the three lighting conditions. The final mineralized products were amine compounds identified by infrared spectrophotometry. When irradiated with visible light, the photocatalytic degradation rate could be improved by lowering the H2O2 concentration and inhibited by increasing the H2O2 concentration, but results contrary to the above were obtained when UV light was used for irradiation.展开更多
Perovskite type oxides LaCoO 3 was prepared by citrate method in granula of 20~30 nm. Using a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried o...Perovskite type oxides LaCoO 3 was prepared by citrate method in granula of 20~30 nm. Using a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3. The results show that the perovskite type oxide LaCoO 3 has good photocatalytic activity. With the study of X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is mainly related with the factors such as the d electron structure of ion Co 3+ , Co O binding energy and adsorbed oxygen on the surface etc.展开更多
Experiments were carried out to study the effects of several anions on the photocatalytic degradation rates of sodium dodecylbenzene sulphonate (DBS) with TiO 2 as catalyst. The anions were added as Na 2SO 4, NaNO ...Experiments were carried out to study the effects of several anions on the photocatalytic degradation rates of sodium dodecylbenzene sulphonate (DBS) with TiO 2 as catalyst. The anions were added as Na 2SO 4, NaNO 3, NaCl, NaHCO 3, NaH 2PO 4 and Na 3PO 4, and two levels of anion content, i.e. 12 mmol/L and 36 mmol/L in terms of Na +, were studied. The results revealed that: Cl -, SO 2- 4, NO - 3 and HCO - 3 retarded the rates of DBS degradation to different degrees; PO 3- 4 increased the DBS degradation rate at low concentration and decreased the rate at high concentration; H 2PO - 4 accelerated the rate of DBS degradation. The mechanism of the effects of anions on DBS degradation was concluded as the following three aspects: anions compete for the radicals; anions are absorbed on the surface of catalyst and block the active site of catalyst; anions added to the solution change the pH value and influence the formation of ·OH radicals and the adsorption of DBS on catalyst.展开更多
Nanocrystalline La^3+-doped TiO2 of 20-30 nm in size was prepared by a sol-gel technique. The photocatalytic activities of the samples were evaluated by the degradation of harmful acid orange 7(AO7) azo-dye in aque...Nanocrystalline La^3+-doped TiO2 of 20-30 nm in size was prepared by a sol-gel technique. The photocatalytic activities of the samples were evaluated by the degradation of harmful acid orange 7(AO7) azo-dye in aqueous solution. The effects of La^3+ ion implantation on the photocatalytic activity of TiO2 were also discussed. The results show that the La^3+ content plays an essential role in affecting the photocatalytic activity of the La^3+-doped TiO2 and the optimum content of La^3+-doped is 1.0 wt.%. The photocatalytic activity of the samples with La^3+-doped TiO2 is higher than that of pure TiO2 in the treatment of AO7 wastewater. The photodegradation effect of AO7 effluent is the best by means of La^3+-doped TiO2 with 1.0% La^3+.展开更多
Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W^6+ with TiO2 because the doped W^6+ th...Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W^6+ with TiO2 because the doped W^6+ that entered into the crystal lattices of TiO2 led to the formation of defects in the crystal lattices of TiO2 and thereby improved the photocatalytic activity of TiO2.When WO3 doped in TiO2 exceeded 3%, the excess W^6+ did not enter into the crystal lattices of TiO2 but were uniformly dispersed in TiO2 or they covered the surface of TiO2, which reduced the effective illumination area of TiO2 and thereby lowered the photocatalytic activity of TiOE.The relationship among the composition of the catalyst, the amount of photocatalyst, the illumination time, and the decolorizing rate of methyl orange (MO) were discussed. The results show that the decolorizing rate of MO can reach 82.3% using WO3/TiO2 as the photocatalyst, with the composition of WO3/TiO2 -3:97, the mass of catalyst = 0.400 g, the initial concentration of MO = 20 mg/L, pH = 6.5, and the illumina- tion time = 7 h.展开更多
In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of...In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of the tetracycline(TC)antibiotic under visible light irradiation.The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C_(3)N_(4)composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83%in 100 min irradiation.The improvement of photocatalytic activity is mainly attributed to the following two points:(i)the strong bonding with π-π stacking between BC and g-C_(3)N_(4)make the photogenerated electrons of light-excited g-C_(3)N_(4)transfer to BC,quickly and improve the separation efficiency of carriers;(ii)the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites.This study provides a sustainable,economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.展开更多
Objective To investigate the photocatalytic degradation of gaseous ammonia in static state by using nano-TiO2 as photoeatalyst supported on latex paint film under UV-irradiation. Methods Experiments were conducted to ...Objective To investigate the photocatalytic degradation of gaseous ammonia in static state by using nano-TiO2 as photoeatalyst supported on latex paint film under UV-irradiation. Methods Experiments were conducted to study the relationship between the initial concentration of ammonia and the degradation products competing to be adsorbed on catalyst surface. Degradation of ammonia and its products were detected by spectrophotometry and catalytic kinetic spectrophotometry, respectively. Results On the one hand, TiO2 catalyst was excellent for degradation of ammonia, and the crystal phase of TiO2, anatase or ruffle, had little effect on degradation of ammonia, but the conversion of ammonia grew with the increase of catalyst content. On the other hand, apparent rate constant and conversion of ammonia decreased with the increase of initial concentration of ammonia, and the photocatalytic degradation reaction followed a pseudo-first-order expression due to-the evidence of linear correlation between -lnC/C0 vs. irradiation time t, but the relationship between initial concentration and the degradation products was not linear in low initial concentration. Conclusion Whether the photocatalytic degradation of ammonia in static state follows a first-order reaction depends on the initial ammonia concentration due to competition in adsorption between reactant and the degradation products.展开更多
CdS quantum dots sensitized platelike WO_3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition(CBD) technique.To further improve the stability of the p...CdS quantum dots sensitized platelike WO_3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition(CBD) technique.To further improve the stability of the photoelectrodes in alkaline environment,the platelike WO_3 films were treated with TiCl_4 to form a nano-TiO_2 buffer layer on the WO_3 plate surface before loading CdSQDs.The resulting electrodes were characterized by using XRD,SEM,HR-TEM and UV-vis spectrum.The photocatalytic activity of the resulting electrodes was investigated by degradation of methyl orange(MO) in aqueous solution.The photoelectrochemical(PEC) property of the resulting electrodes was also characterized by the linear sweep voltammetry.The results of both the degradation of MO and photocurrent tests indicated that the as-prepared CdSQDs sensitized WO_3 platelike photoelectrodes exhibit a significant improvement in photocatalytic degradation and PEC activity under visible light irradiation,compared with unsupported CdSQDs electrodes.Significantly,coating the WO_3 plates with nano-TiO_2 obviously facilitate the charge separation and retards the charge-pair recombination,and results in a highest activity for QDsCdS/TiO_2/WO_3 photoelectrodes.展开更多
A titanium dioxide loaded tremella-like mesoporous calcium silicate hydrate(TiO_(2)@CSH)with both adsorption and photocatalytic degradation activity was successfully prepared by a hydrothermal method combined with sol...A titanium dioxide loaded tremella-like mesoporous calcium silicate hydrate(TiO_(2)@CSH)with both adsorption and photocatalytic degradation activity was successfully prepared by a hydrothermal method combined with sol-gel strategy in two steps in this work.Tremella-shaped CSH provides abundant active sites for accommodating of TiO_(2),thus the corresponding TiO_(2)@CSH achieved a high loading ratio of 36.73%.Such a special shaped TiO_(2)@CSH exhibits excellent pre-enrichment capacity and photocatalytic degradation capacity for organic pollutants.Bisphenol A(BPA)removal experiments show that TiO_(2)@CSH can remove 91.17%of BPA from aqueous solutions.Studies on removal mechanism suggest that BPA tends to bind on the interface between CSH and TiO_(2) and the pre-enrichment process conforms to the intraparticle diffusion model;and then,it is decomposed to harmless substances of CO_(2) and H_(2)O during the photocatalytic process.The experimental results show that loading functional nanoparticles such as TiO_(2) on the surface of inorganic porous materials can endow inert porous materials with new functions such as photocatalytic degradation,which effectively expands the application range of inorganic porous materials.展开更多
The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precurs...The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction(XRD), transmission electron microscopy(TEM), vibrating sample magnetometry(VSM), diffuse reflectance spectroscopy(DRS), and ultraviolet–visible(UV-Vis) spectroscopy. The effects of irradiation time, methylene blue(MB) concentration, catalyst dosage, and p H value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m^3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.展开更多
Kinetics of photocatalytic degradation of methylene blue(MB) over Ca Ti O3 was studied. Effects of the solution p H, the MB concentration, the Ca Ti O3 dosage, and the type of light source on photocatalytic degradatio...Kinetics of photocatalytic degradation of methylene blue(MB) over Ca Ti O3 was studied. Effects of the solution p H, the MB concentration, the Ca Ti O3 dosage, and the type of light source on photocatalytic degradation rate of MB over Ca Ti O3 were investigated in detail. The results show that photocatalytic degradation of MB over Ca Ti O3 followed the first-order reaction. The apparent rate constant(kobs) of MB significantly increased with increasing solution p H while it greatly decreased with increasing MB concentration. The kobs of MB increased with increasing Ca Ti O3 dosage from 0.05 to 0.1 g, whereas it slightly decreased with increasing Ca Ti O3 dosage in the range of 0.1-0.4 g. The kobs of MB under UV-visible light irradiation was larger by factors of 2.2 than that under visible light irradiation. The kobs of MB was(4.8±0.3)×10-1h-1 under optimal conditions with the solution p H of 11, the MB concentration of 1 ppm, the Ca Ti O3 dosage of 0.1 g, and UV-visible light irradiation.展开更多
Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied...Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are: Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO3^- and SO4^2-. Chemical oxygen demand(COD) measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions reauired Iona dearadation time.展开更多
Layered double hydroxide(LDH)with special layered structure has been proved to have excellent hole transport capacity and good stability.Herein,we report a high efficient composite photocatalyst of CoAlLDH and BiPO4pr...Layered double hydroxide(LDH)with special layered structure has been proved to have excellent hole transport capacity and good stability.Herein,we report a high efficient composite photocatalyst of CoAlLDH and BiPO4prepared by hydrothermal and che mical adsorption(denoted as CoAl-LDH/BiPO_(4)).Phenol can be entirely degraded by 1%CoAl-LDH/BiPO_(4)under 30 min ultraviolet(UV)light irradiation,and the degradation rate constants k are 3 times and 39 times higher than that of pure BiPO_(4)and CoAl-LDH,respectively.The enhanced photocatalytic activity can be attributed to effective holes transfer from BiPO4to CoAl-LDH,which hinders the recombination of photo genera ted charge carriers.In addition,the combination of BiPO4and CoAl-LDH avoids the agglomeration of BiPO4and improves the stability of BiPO_(4).Active species capture experiments indicate that superoxide radicals(·O-_(2))are the main active species responsible for the degradation of phenol.This work provides technical approaches and research ideas for solving the photogenerated charge carrier recombination problem of photocatalyst.展开更多
In situ FTIR spectroscopy was utilized to investigate the magnetic field effect on the heterogeneous photocatalytic degradation of benzene over platinized titania (Pt/TiO2). The results revealed that the employment ...In situ FTIR spectroscopy was utilized to investigate the magnetic field effect on the heterogeneous photocatalytic degradation of benzene over platinized titania (Pt/TiO2). The results revealed that the employment of magnetic field may not change the mechanism of photocatalytic degradation of benzene, however, it greatly facilitate the conversion of benzene to phenol and quinone, as well as the transformation from phenol to quinone, resulting in opening the benzene ring easily and promoting the production of CO2.展开更多
In this paper,La(3)-doped Nano-TiO2(La(3)-TiO2) was synthesized via hydrothermal process.Structure and optical properties of the synthesized samples were characterized via XRD,FT-IR,DRS,etc.The results showed th...In this paper,La(3)-doped Nano-TiO2(La(3)-TiO2) was synthesized via hydrothermal process.Structure and optical properties of the synthesized samples were characterized via XRD,FT-IR,DRS,etc.The results showed that the phase transformation of TiO2 from anatase to rutile was effectively prevented by La(3)-doping,which improved the thermal stability of anatase,and also suppressed particle aggregation and grain growth of TiO2.The formation of Ti-O-La bond promoted UV absorption intensity of TiO2,and provoked red shift of absorbed light.And the spectra response range of TiO2 was extended significantly to visible light by La(3)-doping,then photocatalytic performance was improved effectively.Compared with pure nano-TiO2,the performance of La(3)-TiO2 which photocatalyticly degraded methyl orange was increased significantly.展开更多
The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was...The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was effective for the improvement of efficiency for the photocatalytic degradation of bisphenol A in water. The optimum doping concentration of silver was found to be 3 wt%. The pseudo first-order rate constant with 3 wt% Ag/ZnO was 1.3 times better compared with bare ZnO. The photocatalytic degradation of treatment for the wastewater containing bisphenol A is simple, easy handling and low cost.展开更多
Photocatalytic oxidation techniques are promising for degradation of the highly ecotoxic and refractory isothiazolinone bactericides in relevant industrial wastewaters.However,low charge separation and directional tra...Photocatalytic oxidation techniques are promising for degradation of the highly ecotoxic and refractory isothiazolinone bactericides in relevant industrial wastewaters.However,low charge separation and directional transport efficiency under solar light radiation restrain their practical application.Here,we report a nanostructured photocatalyst doped with Gd and B in TiO_(2)with carbon incorporation and defect formation through incomplete calcination.The specific surface area,grain size,and hydrophilicity of TiO_(2)are improved,which is beneficial for the interfacial reaction between the photocatalyst and pollutants.The reduction of the bandgap,the broadening of the photo-absorption range,and the retarded electron-hole recombination promote the photocatalytic performance due to the improved oxygen vacancies based on the electron distribution modification.The difference in partial density of states(ΔPDOS)between the current catalyst and raw TiO_(2)indicates that the co-doping of Gd and B with incomplete calcination changes the electronic hybridization of conduction band and valence band near the Fermi level,and affects the band gap energy.It improved charge separation and directional transport efficiency and benefited the formation of main active species,including•OH and O_(2)•−,for the pollutant decomposition.The rate of photocatalytic removal of benzisothiazolinone(BIT)by the current photocatalyst reaches 1.25 h^(−1),being 4.31 times that of TiO_(2).The current work offers a constructive approach to the design and synthesis of nanostructured photocatalysts for the photocatalytic degradation of refractory organic pollutants.展开更多
A novel tetra-nuclear Tb-organic network,named as [Tb_(4)(2-pyia)_(6)(HAc)_(0.5)(2,2'-bipy)(H_(2)O)_(4.5)]·2,2'-bipy·H_(2)O(1),was synthesized hydrothermally based on 5-(pyridin-2-ylmethoxy) isophtha...A novel tetra-nuclear Tb-organic network,named as [Tb_(4)(2-pyia)_(6)(HAc)_(0.5)(2,2'-bipy)(H_(2)O)_(4.5)]·2,2'-bipy·H_(2)O(1),was synthesized hydrothermally based on 5-(pyridin-2-ylmethoxy) isophthalic acid(H_(2)pyia) and 2,2'-bipyridine(2,2'-bipy) ligands,and characterized by single crystal X-ray diffraction,thermogravimetric(TG) analyses,powder X-ray diffraction(PXRD) and infrared(IR) technology.1 possesses a two-dimensional network based on the tetra-nuclear inorganic building units,and the π-πstacking interactions between the pyia^(2-) ligands and the guest 2,2'-bipy molecules play an important role in the forming of 3D supramolecular structure.1 exhibits excellent fluorescent sensing performance for Fe^(3+)(1.26×10^(-8) mol/L),Cr_(2)O_(7)^(2-)(8.1×10^(-7) mol/L),2,4,6-trinitrophenol(TNP)(2.71×10^(-8) mol/L)and tetracycline(TCT)(2.76×10^(-7) mol/L) in aqueous solution with lower detection concentrations.The sensing mechanisms of 1 were investigated by density functional theory(DFT) calculations,ultraviolet-visible(UV-Vis) diffuse reflectance spectroscopy,PXRD and fluorescent lifetime analyses.The activated product of 1 was prepared by heating at 255℃ under constant pressure and used to photo-catalytically degrade TCT.Both 1 and the activated one have good photocatalytic degradation performance for TCT with degradation rates of 84.29% and 96.07%,respectively.The photocatalytic mechanisms were discovered by UV-Vis diffuse reflectance spectroscopy and radical trap experiments.The Tb-organic framework might be an excellent multifunctional fluorescent sensor and a good photocatalytic agent for TCT degradation in the future.展开更多
The utilization of an efficient photocatalyst is crucial for the photocatalytic degradation of antibiotics in water through visible light,which is an imperative requirement for the remediation of water environments.In...The utilization of an efficient photocatalyst is crucial for the photocatalytic degradation of antibiotics in water through visible light,which is an imperative requirement for the remediation of water environments.In this study,a novel Cu-CeO_(2)/BiOBr Z-type heterojunction was synthesized by calcination and hydrothermal methods,and the degradation rate of sulfathiazole(STZ)antibiotic solution was studied using simulated illumination(300 W xenon lamp).The results indicated that 3%Cu-CeO_(2)/BiOBr achieved a degradation rate of 92.3%within 90 min when treating 20 mg/L STZ solution,demonstrating its potential for practical water treatment applications.Characterization using various chemical instruments revealed that 3%Cu-CeO_(2)/Bi OBr exhibited the lowest electron-hole recombination rate and electron transfer resistance.Furthermore,the utilization of ESR data and quenching experiments has substantiated the involvement of hydroxyl radicals(·OH)and superoxide radicals(·O_(2)^(-))as the primary active species.Consequently,a plausible degradation mechanism has been inferred.These findings offer a prospective approach for the development of heterojunction materials with appropriate band matching.展开更多
It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional(3D)hierarchical nanostructures and constructing oxygen vacancies(VOs).Howev...It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional(3D)hierarchical nanostructures and constructing oxygen vacancies(VOs).However,controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing VOs in photocatalysts remains a challenge.Herein,we reported an ethylene glycol(EG)mediated approach to craft 3D hydrangea-structure Bi_(2)MoO_(6)with VOs for efficient photocatalytic degradation of tetracycline.Through manipulating the EG concentration during the fabrication process,the influence of EG concentration on the Bi_(2)MoO_(6)structure was systematically investigated.EG could promote the self-assembly of Bi_(2)MoO_(6)nanosheets to form a 3D hierarchical structure.Compared with 2D nanoplates,3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi_(2)MoO_(6).In addition,the reduction effect of EG on metallic oxide enabled the generation of VOs in Bi_(2)MoO_(6).The VOs adjusted the electronic structure of Bi_(2)MoO_(6),which not only enhanced the light harvesting,but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species(·O2−and·OH)for the efficient tetracycline decomposition.3D Bi_(2)MoO_(6)hydrangea with VOs achieved a 79.4%removal efficiency of tetracycline after 75 min.This work provides a simple yet robust EG-mediated strategy,which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures,but also crafts tunable VOs for highly efficient photocatalysis.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 20373074) the National Basic Research Programme (973) of China (No. 2003CB415006-3).
文摘The photocatalytic degradation of dye pollutant sulforhodamine-B (SRB) in aqueous titanium dioxide (TiO2) dispersions was examined under three lighting regimes: UV light (330 nm〈λ〈 380 nm), sunlight, and visible light (λ〉450 nm), all investigated at pH=2.5. Total organic carbon (TOC) and chemical oxygen demand (CODer) assays show that the degradation rate of SRB is much higher when irradiated with UV and sunlight compared with visible light. The temporal concentration changes of SRB illustrated a first-order reaction and the rate constant, k, is 0.197 min^-1, 0.152 min^-1, 0.027 min^-1, respectively, under the three lighting conditions. The final mineralized products were amine compounds identified by infrared spectrophotometry. When irradiated with visible light, the photocatalytic degradation rate could be improved by lowering the H2O2 concentration and inhibited by increasing the H2O2 concentration, but results contrary to the above were obtained when UV light was used for irradiation.
文摘Perovskite type oxides LaCoO 3 was prepared by citrate method in granula of 20~30 nm. Using a fluorescent Hg lamp or sunlight as irradiator, the degradation experiments of various water soluble dyes were carried out in the suspension system of LaCoO 3. The results show that the perovskite type oxide LaCoO 3 has good photocatalytic activity. With the study of X ray photoelectron spectroscopy and photoacoustic spectra, its photocatalytic activity is mainly related with the factors such as the d electron structure of ion Co 3+ , Co O binding energy and adsorbed oxygen on the surface etc.
基金TheNationalNaturalScienceFoundationofChina (No .495 710 6 2 )
文摘Experiments were carried out to study the effects of several anions on the photocatalytic degradation rates of sodium dodecylbenzene sulphonate (DBS) with TiO 2 as catalyst. The anions were added as Na 2SO 4, NaNO 3, NaCl, NaHCO 3, NaH 2PO 4 and Na 3PO 4, and two levels of anion content, i.e. 12 mmol/L and 36 mmol/L in terms of Na +, were studied. The results revealed that: Cl -, SO 2- 4, NO - 3 and HCO - 3 retarded the rates of DBS degradation to different degrees; PO 3- 4 increased the DBS degradation rate at low concentration and decreased the rate at high concentration; H 2PO - 4 accelerated the rate of DBS degradation. The mechanism of the effects of anions on DBS degradation was concluded as the following three aspects: anions compete for the radicals; anions are absorbed on the surface of catalyst and block the active site of catalyst; anions added to the solution change the pH value and influence the formation of ·OH radicals and the adsorption of DBS on catalyst.
基金[This work was financially supported by the Science and Technology Department Foundation of Hunan Province (No. 02JJY2015), and the Doctorate Foundation of Changsha University of Science and Technology (No. 04xxrc037).]
文摘Nanocrystalline La^3+-doped TiO2 of 20-30 nm in size was prepared by a sol-gel technique. The photocatalytic activities of the samples were evaluated by the degradation of harmful acid orange 7(AO7) azo-dye in aqueous solution. The effects of La^3+ ion implantation on the photocatalytic activity of TiO2 were also discussed. The results show that the La^3+ content plays an essential role in affecting the photocatalytic activity of the La^3+-doped TiO2 and the optimum content of La^3+-doped is 1.0 wt.%. The photocatalytic activity of the samples with La^3+-doped TiO2 is higher than that of pure TiO2 in the treatment of AO7 wastewater. The photodegradation effect of AO7 effluent is the best by means of La^3+-doped TiO2 with 1.0% La^3+.
基金This work was financially supported by the Natural Science Foundation of Anhui Province, China (No. 050450301).
文摘Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W^6+ with TiO2 because the doped W^6+ that entered into the crystal lattices of TiO2 led to the formation of defects in the crystal lattices of TiO2 and thereby improved the photocatalytic activity of TiO2.When WO3 doped in TiO2 exceeded 3%, the excess W^6+ did not enter into the crystal lattices of TiO2 but were uniformly dispersed in TiO2 or they covered the surface of TiO2, which reduced the effective illumination area of TiO2 and thereby lowered the photocatalytic activity of TiOE.The relationship among the composition of the catalyst, the amount of photocatalyst, the illumination time, and the decolorizing rate of methyl orange (MO) were discussed. The results show that the decolorizing rate of MO can reach 82.3% using WO3/TiO2 as the photocatalyst, with the composition of WO3/TiO2 -3:97, the mass of catalyst = 0.400 g, the initial concentration of MO = 20 mg/L, pH = 6.5, and the illumina- tion time = 7 h.
基金the founding support from the National Natural Science Foundation of China (21906072, 22006057 and 31971616)the Natural Science Foundation of Jiangsu Province (BK20190982)+4 种基金“Doctor of Mass Entrepreneurship and Innovation” Project in Jiangsu ProvinceHenan Postdoctoral Foundation (202003013)the Science and Technology Research Project of the Department of Education of Jilin Province (JJKH20200039KJ)the Science and Technology Research Project of Jilin City (20190104120, 201830811)the Project of Jilin Provincial Science and Technology Development Plan (20190201277JC, 20200301046RQ, YDZJ202101ZYTS070)
文摘In this study,biochar(BC)derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride(g-C_(3)N_(4))to synthesize the BC/g-C_(3)N_(4)composite for the degradation of the tetracycline(TC)antibiotic under visible light irradiation.The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C_(3)N_(4)composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83%in 100 min irradiation.The improvement of photocatalytic activity is mainly attributed to the following two points:(i)the strong bonding with π-π stacking between BC and g-C_(3)N_(4)make the photogenerated electrons of light-excited g-C_(3)N_(4)transfer to BC,quickly and improve the separation efficiency of carriers;(ii)the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites.This study provides a sustainable,economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.
基金This work has been supported by Shandong Provincial Scientific Council, People’s Republic of China (Grant No. Z2000B01)
文摘Objective To investigate the photocatalytic degradation of gaseous ammonia in static state by using nano-TiO2 as photoeatalyst supported on latex paint film under UV-irradiation. Methods Experiments were conducted to study the relationship between the initial concentration of ammonia and the degradation products competing to be adsorbed on catalyst surface. Degradation of ammonia and its products were detected by spectrophotometry and catalytic kinetic spectrophotometry, respectively. Results On the one hand, TiO2 catalyst was excellent for degradation of ammonia, and the crystal phase of TiO2, anatase or ruffle, had little effect on degradation of ammonia, but the conversion of ammonia grew with the increase of catalyst content. On the other hand, apparent rate constant and conversion of ammonia decreased with the increase of initial concentration of ammonia, and the photocatalytic degradation reaction followed a pseudo-first-order expression due to-the evidence of linear correlation between -lnC/C0 vs. irradiation time t, but the relationship between initial concentration and the degradation products was not linear in low initial concentration. Conclusion Whether the photocatalytic degradation of ammonia in static state follows a first-order reaction depends on the initial ammonia concentration due to competition in adsorption between reactant and the degradation products.
基金Project(2014FJ3041)supported by the Research Funds of Science and Technology Agency of Hunan Provincial,ChinaProject(14A076)supported by the Research Funds of Education Agency of Hunan Provincial,ChinaProject supported by the Postdoctoral Science Foundation of Central South University,China
文摘CdS quantum dots sensitized platelike WO_3 photoelectrodes were successfully synthesized by a facile hydrothermal method and a modified chemical bath deposition(CBD) technique.To further improve the stability of the photoelectrodes in alkaline environment,the platelike WO_3 films were treated with TiCl_4 to form a nano-TiO_2 buffer layer on the WO_3 plate surface before loading CdSQDs.The resulting electrodes were characterized by using XRD,SEM,HR-TEM and UV-vis spectrum.The photocatalytic activity of the resulting electrodes was investigated by degradation of methyl orange(MO) in aqueous solution.The photoelectrochemical(PEC) property of the resulting electrodes was also characterized by the linear sweep voltammetry.The results of both the degradation of MO and photocurrent tests indicated that the as-prepared CdSQDs sensitized WO_3 platelike photoelectrodes exhibit a significant improvement in photocatalytic degradation and PEC activity under visible light irradiation,compared with unsupported CdSQDs electrodes.Significantly,coating the WO_3 plates with nano-TiO_2 obviously facilitate the charge separation and retards the charge-pair recombination,and results in a highest activity for QDsCdS/TiO_2/WO_3 photoelectrodes.
基金Funded by the Beijing Natural Science Foundation(No.2192016)the Beijing Natural Science Foundation and the Key Scientific Project of Beijing Municipal Education Commission(No.KZ202110011018)。
文摘A titanium dioxide loaded tremella-like mesoporous calcium silicate hydrate(TiO_(2)@CSH)with both adsorption and photocatalytic degradation activity was successfully prepared by a hydrothermal method combined with sol-gel strategy in two steps in this work.Tremella-shaped CSH provides abundant active sites for accommodating of TiO_(2),thus the corresponding TiO_(2)@CSH achieved a high loading ratio of 36.73%.Such a special shaped TiO_(2)@CSH exhibits excellent pre-enrichment capacity and photocatalytic degradation capacity for organic pollutants.Bisphenol A(BPA)removal experiments show that TiO_(2)@CSH can remove 91.17%of BPA from aqueous solutions.Studies on removal mechanism suggest that BPA tends to bind on the interface between CSH and TiO_(2) and the pre-enrichment process conforms to the intraparticle diffusion model;and then,it is decomposed to harmless substances of CO_(2) and H_(2)O during the photocatalytic process.The experimental results show that loading functional nanoparticles such as TiO_(2) on the surface of inorganic porous materials can endow inert porous materials with new functions such as photocatalytic degradation,which effectively expands the application range of inorganic porous materials.
基金financial support of University of Tehran for this researchfinancial support of Iran Nanotechnology Initiative Council
文摘The photocatalytic performance of mechano-thermally synthesized Fe/FeS nanostructures formed from micron-sized starting materials was compared with that of a thermally synthesized nanostructure with nano-sized precursors in this paper. The properties of as-synthesized materials were studied by X-ray diffraction(XRD), transmission electron microscopy(TEM), vibrating sample magnetometry(VSM), diffuse reflectance spectroscopy(DRS), and ultraviolet–visible(UV-Vis) spectroscopy. The effects of irradiation time, methylene blue(MB) concentration, catalyst dosage, and p H value upon the degradation of MB were studied. Magnetic properties of the samples showed that both as-synthesized Fe/FeS photocatalysts are magnetically recoverable, eliminating the need for conventional filtration steps. Degradation of 5 ppm of the MB solution by mechano-thermally synthesized Fe/FeS with a photocatalyst dosage of 1 kg/m^3 at pH 11 can reach 96% after 12 ks irradiation under visible light. The photocatalytic efficiency is higher in alkaline solution. The kinetics of photocatalytic degradation in both samples is controlled by a first-order reaction. However, the rate-constant value in the thermally synthesized Fe/FeS photocatalyst sample is only 1.5 times greater than that of the mechano-thermally synthesized one.
基金Funded by the National Natural Science Foundation of China(No.21407020)the Fundamental Research Fund for the Central Universities(No.N130302004)
文摘Kinetics of photocatalytic degradation of methylene blue(MB) over Ca Ti O3 was studied. Effects of the solution p H, the MB concentration, the Ca Ti O3 dosage, and the type of light source on photocatalytic degradation rate of MB over Ca Ti O3 were investigated in detail. The results show that photocatalytic degradation of MB over Ca Ti O3 followed the first-order reaction. The apparent rate constant(kobs) of MB significantly increased with increasing solution p H while it greatly decreased with increasing MB concentration. The kobs of MB increased with increasing Ca Ti O3 dosage from 0.05 to 0.1 g, whereas it slightly decreased with increasing Ca Ti O3 dosage in the range of 0.1-0.4 g. The kobs of MB under UV-visible light irradiation was larger by factors of 2.2 than that under visible light irradiation. The kobs of MB was(4.8±0.3)×10-1h-1 under optimal conditions with the solution p H of 11, the MB concentration of 1 ppm, the Ca Ti O3 dosage of 0.1 g, and UV-visible light irradiation.
文摘Aqueous solutions of azo dyes undergo degradation to form harmless intermediates and colorless products following irradiation by visible light in the presence of titanium dioxide thin films. The dyes that were studied in this work are: Chicago Sky Blue 6B and Benzopurpurin 4B. Results obtained indicated that complete mineralization of the dyes took place under the experimental conditions. There was an increase in conductivity after the complete mineralization experiments possibly indicating the formation of ions such as NO3^- and SO4^2-. Chemical oxygen demand(COD) measurements show a decrease in organic matter for both dyes following complete degradation. The effect of how changing experimental conditions such as pH, temperature and starting concentrations of dyes affected the rate of dye degradation was measured. There was an increase in the rate of disappearance of the dye color at lower pH. High concentrations of dye solutions reauired Iona dearadation time.
基金supported by the National Key Research and Development Program of China [2019YFC1904500]National Natural Science Foundation of China [52270115, 21878331, 21777080]Science Foundation of China University of Petroleum, Beijing [2462019QNXZ05, 2462020YXZZ018]
文摘Layered double hydroxide(LDH)with special layered structure has been proved to have excellent hole transport capacity and good stability.Herein,we report a high efficient composite photocatalyst of CoAlLDH and BiPO4prepared by hydrothermal and che mical adsorption(denoted as CoAl-LDH/BiPO_(4)).Phenol can be entirely degraded by 1%CoAl-LDH/BiPO_(4)under 30 min ultraviolet(UV)light irradiation,and the degradation rate constants k are 3 times and 39 times higher than that of pure BiPO_(4)and CoAl-LDH,respectively.The enhanced photocatalytic activity can be attributed to effective holes transfer from BiPO4to CoAl-LDH,which hinders the recombination of photo genera ted charge carriers.In addition,the combination of BiPO4and CoAl-LDH avoids the agglomeration of BiPO4and improves the stability of BiPO_(4).Active species capture experiments indicate that superoxide radicals(·O-_(2))are the main active species responsible for the degradation of phenol.This work provides technical approaches and research ideas for solving the photogenerated charge carrier recombination problem of photocatalyst.
基金This work was supported financially by the National Natural Science Foundation of China(No.20133010)Education Department of Fujian(No.JB04238).
文摘In situ FTIR spectroscopy was utilized to investigate the magnetic field effect on the heterogeneous photocatalytic degradation of benzene over platinized titania (Pt/TiO2). The results revealed that the employment of magnetic field may not change the mechanism of photocatalytic degradation of benzene, however, it greatly facilitate the conversion of benzene to phenol and quinone, as well as the transformation from phenol to quinone, resulting in opening the benzene ring easily and promoting the production of CO2.
基金Supported by Fujian High-tech Project Foundation (No 2004H008)
文摘In this paper,La(3)-doped Nano-TiO2(La(3)-TiO2) was synthesized via hydrothermal process.Structure and optical properties of the synthesized samples were characterized via XRD,FT-IR,DRS,etc.The results showed that the phase transformation of TiO2 from anatase to rutile was effectively prevented by La(3)-doping,which improved the thermal stability of anatase,and also suppressed particle aggregation and grain growth of TiO2.The formation of Ti-O-La bond promoted UV absorption intensity of TiO2,and provoked red shift of absorbed light.And the spectra response range of TiO2 was extended significantly to visible light by La(3)-doping,then photocatalytic performance was improved effectively.Compared with pure nano-TiO2,the performance of La(3)-TiO2 which photocatalyticly degraded methyl orange was increased significantly.
文摘The metal-doping into the photocatalyst was evaluated for the photocatalytic degradation of bisphenol A in aqueous solution with ZnO powder. Au/ZnO, Ag/ZnO and Cu/ZnO were tested in the present work. Ag-doping ZnO was effective for the improvement of efficiency for the photocatalytic degradation of bisphenol A in water. The optimum doping concentration of silver was found to be 3 wt%. The pseudo first-order rate constant with 3 wt% Ag/ZnO was 1.3 times better compared with bare ZnO. The photocatalytic degradation of treatment for the wastewater containing bisphenol A is simple, easy handling and low cost.
基金the National Key R&D Program of China(No.2021YFC2102205)the National Natural Science Foundation of China(No.51808312)the CNNC Key Laboratory on Uranium Extraction from Seawater(No.KLUES202207).
文摘Photocatalytic oxidation techniques are promising for degradation of the highly ecotoxic and refractory isothiazolinone bactericides in relevant industrial wastewaters.However,low charge separation and directional transport efficiency under solar light radiation restrain their practical application.Here,we report a nanostructured photocatalyst doped with Gd and B in TiO_(2)with carbon incorporation and defect formation through incomplete calcination.The specific surface area,grain size,and hydrophilicity of TiO_(2)are improved,which is beneficial for the interfacial reaction between the photocatalyst and pollutants.The reduction of the bandgap,the broadening of the photo-absorption range,and the retarded electron-hole recombination promote the photocatalytic performance due to the improved oxygen vacancies based on the electron distribution modification.The difference in partial density of states(ΔPDOS)between the current catalyst and raw TiO_(2)indicates that the co-doping of Gd and B with incomplete calcination changes the electronic hybridization of conduction band and valence band near the Fermi level,and affects the band gap energy.It improved charge separation and directional transport efficiency and benefited the formation of main active species,including•OH and O_(2)•−,for the pollutant decomposition.The rate of photocatalytic removal of benzisothiazolinone(BIT)by the current photocatalyst reaches 1.25 h^(−1),being 4.31 times that of TiO_(2).The current work offers a constructive approach to the design and synthesis of nanostructured photocatalysts for the photocatalytic degradation of refractory organic pollutants.
基金Project supported by the National Natural Science Foundation of China(22063010)the Youth Innovation Team of Shaanxi Universities。
文摘A novel tetra-nuclear Tb-organic network,named as [Tb_(4)(2-pyia)_(6)(HAc)_(0.5)(2,2'-bipy)(H_(2)O)_(4.5)]·2,2'-bipy·H_(2)O(1),was synthesized hydrothermally based on 5-(pyridin-2-ylmethoxy) isophthalic acid(H_(2)pyia) and 2,2'-bipyridine(2,2'-bipy) ligands,and characterized by single crystal X-ray diffraction,thermogravimetric(TG) analyses,powder X-ray diffraction(PXRD) and infrared(IR) technology.1 possesses a two-dimensional network based on the tetra-nuclear inorganic building units,and the π-πstacking interactions between the pyia^(2-) ligands and the guest 2,2'-bipy molecules play an important role in the forming of 3D supramolecular structure.1 exhibits excellent fluorescent sensing performance for Fe^(3+)(1.26×10^(-8) mol/L),Cr_(2)O_(7)^(2-)(8.1×10^(-7) mol/L),2,4,6-trinitrophenol(TNP)(2.71×10^(-8) mol/L)and tetracycline(TCT)(2.76×10^(-7) mol/L) in aqueous solution with lower detection concentrations.The sensing mechanisms of 1 were investigated by density functional theory(DFT) calculations,ultraviolet-visible(UV-Vis) diffuse reflectance spectroscopy,PXRD and fluorescent lifetime analyses.The activated product of 1 was prepared by heating at 255℃ under constant pressure and used to photo-catalytically degrade TCT.Both 1 and the activated one have good photocatalytic degradation performance for TCT with degradation rates of 84.29% and 96.07%,respectively.The photocatalytic mechanisms were discovered by UV-Vis diffuse reflectance spectroscopy and radical trap experiments.The Tb-organic framework might be an excellent multifunctional fluorescent sensor and a good photocatalytic agent for TCT degradation in the future.
基金supported by the National Natural Science Foundation of China(Nos.21471103,52372212)。
文摘The utilization of an efficient photocatalyst is crucial for the photocatalytic degradation of antibiotics in water through visible light,which is an imperative requirement for the remediation of water environments.In this study,a novel Cu-CeO_(2)/BiOBr Z-type heterojunction was synthesized by calcination and hydrothermal methods,and the degradation rate of sulfathiazole(STZ)antibiotic solution was studied using simulated illumination(300 W xenon lamp).The results indicated that 3%Cu-CeO_(2)/BiOBr achieved a degradation rate of 92.3%within 90 min when treating 20 mg/L STZ solution,demonstrating its potential for practical water treatment applications.Characterization using various chemical instruments revealed that 3%Cu-CeO_(2)/Bi OBr exhibited the lowest electron-hole recombination rate and electron transfer resistance.Furthermore,the utilization of ESR data and quenching experiments has substantiated the involvement of hydroxyl radicals(·OH)and superoxide radicals(·O_(2)^(-))as the primary active species.Consequently,a plausible degradation mechanism has been inferred.These findings offer a prospective approach for the development of heterojunction materials with appropriate band matching.
基金the National Key Research and Development Program of China(No.2021YFB3600701)the National Natural Science Foundation of China(Nos.61922090,22022602,and U23B20166).
文摘It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional(3D)hierarchical nanostructures and constructing oxygen vacancies(VOs).However,controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing VOs in photocatalysts remains a challenge.Herein,we reported an ethylene glycol(EG)mediated approach to craft 3D hydrangea-structure Bi_(2)MoO_(6)with VOs for efficient photocatalytic degradation of tetracycline.Through manipulating the EG concentration during the fabrication process,the influence of EG concentration on the Bi_(2)MoO_(6)structure was systematically investigated.EG could promote the self-assembly of Bi_(2)MoO_(6)nanosheets to form a 3D hierarchical structure.Compared with 2D nanoplates,3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi_(2)MoO_(6).In addition,the reduction effect of EG on metallic oxide enabled the generation of VOs in Bi_(2)MoO_(6).The VOs adjusted the electronic structure of Bi_(2)MoO_(6),which not only enhanced the light harvesting,but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species(·O2−and·OH)for the efficient tetracycline decomposition.3D Bi_(2)MoO_(6)hydrangea with VOs achieved a 79.4%removal efficiency of tetracycline after 75 min.This work provides a simple yet robust EG-mediated strategy,which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures,but also crafts tunable VOs for highly efficient photocatalysis.