RESUMO
The nanoparticle-induced dose enhancement effect has been shown to improve the therapeutic efficacy of ionizing radiation in external beam radiotherapy. Whereas previous studies have focused on gold nanoparticles (AuNPs), no quantitative studies have been conducted to investigate the potential superiority of other high atomic number (Z) nanomaterials such as bismuth-based nanoparticles. The aims of this study were to experimentally validate and quantify the dose enhancement properties of commercially available bismuth-based nanoparticles (bismuth oxide (Bi2O3-NPs) and bismuth sulfide (Bi2S3-NPs)), and investigate their potential superiority over AuNPs in terms of radiation dose enhancement. Phantom cuvettes doped with and without nanoparticles where employed for measuring radiation dose enhancement produced from the interaction of radiation with metal nanoparticles. Novel 3D phantoms were employed to investigate the 3D spatial distribution of ionising radiation dose deposition. The phantoms were irradiated with kilovoltage and megavoltage X-ray beams and optical absorption changes were measured using a spectrophotometer and optical CT scanner. The radiation dose enhancement factors (DEFs) obtained for 50 nm diameter Bi2O3-NPs and AuNPs were 1.90 and 1.77, respectively, for 100 kV energy and a nanoparticle concentration of 0.5 mM. In addition, the DEFs of 5 nm diameter Bi2S3-NPs and AuNPs were determined to be 1.38 and 1.51, respectively, for 150 kV energy and a nanoparticle concentration of 0.25 mM. The results demonstrate that both bismuth-based nanoparticles can enhance the effects of radiation. For 6 MV energy the DEFs for all the investigated nanoparticles were lower (< 15%) than with kilovoltage energy.
Assuntos
Bismuto/química , Bismuto/efeitos da radiação , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Radiossensibilizantes/química , Radiossensibilizantes/efeitos da radiação , Absorção de Radiação , Teste de Materiais , Doses de Radiação , Radiometria/métodos , Espalhamento de RadiaçãoRESUMO
Photocatalytic degradation is an alternative method to remove pharmaceutical compounds in water, however it is hard to achieve efficient rate because of the poor solubility of pharmaceutical compounds in water. This study investigated the photodegradation of norfloxacin in a nonionic surfactant Triton-X100 (TX100)/Bi2WO6 dispersion under visible light irradiation (400-750nm). It was found that the degradation of poorly soluble NOF can be strongly enhanced with the addition of TX100. TX100 was adsorbed strongly on Bi2WO6 surface and accelerated NOF photodegradation at the critical micelle concentration (CMC=0.25mM). Higher TX100 concentration (>0.25mM) lowered the degradation rate. In the presence of TX100, the degradation rate reached the maximum value when the pH value was 8.06. FTIR analyses demonstrated that the adsorbed NOF on the catalyst was completely degraded after 2h irradiation. According to the intermediates identified by HPLC/MS/MS, three possible degradation pathways were proposed to include addition of hydroxyl radical to quinolone ring, elimination of piperazynilic ring in fluoroquinolone molecules, and replacement of F atoms on the aromatic ring by hydroxyl radicals.
Assuntos
Antibacterianos/química , Bismuto/química , Norfloxacino/química , Octoxinol/química , Tensoativos/química , Compostos de Tungstênio/química , Antibacterianos/toxicidade , Bismuto/efeitos da radiação , Catálise , Escherichia coli/efeitos dos fármacos , Luz , Norfloxacino/toxicidade , Fotólise , Compostos de Tungstênio/efeitos da radiaçãoRESUMO
The challenge of fine compositional tuning and microstructure control in complex oxides is overcome by developing a general two-step synthetic approach. Antimony-alloyed bismuth vanadate, which is identified as a novel light absorber for solar fuel applications, is prepared in a wide compositional range. The bandgap of this quaternary oxide linearly decreases with the Sb content, in agreement with first-principles calculations.
Assuntos
Antimônio/química , Antimônio/efeitos da radiação , Bismuto/química , Bismuto/efeitos da radiação , Luz , Vanadatos/química , Vanadatos/efeitos da radiação , Ligas/química , Ligas/efeitos da radiação , Modelos Químicos , Oxirredução , Processos Fotoquímicos , Energia Solar , Análise Espectral , Difração de Raios XRESUMO
Herein, a facile strategy for the controllable synthesis of BiVO4@C core-shell nanoparticles on reduced graphene oxide (RGO) is reported. The BiVO4 particle size can be controlled in the process by adjusting the volume ratio of glycerol in the sol-gel solution. The glycerol layers adsorbed on BiVO4 (BiVO4@glycerol) made it possible to form hydrogen bonds between BiVO4@glycerol and graphene oxide with the assistance of ultrasound. After thermal treatment, glycerol adsorbed on the BiVO4 particles formed amorphous carbon shells to link the particles and RGO. As a result, the obtained RGO-BiVO4@C nanocomposite showed a five times higher rate in O2 evolution from water under visible-light irradiation. Also, it demonstrated a six times higher photocatalytic performance enhancement than that of pure BiVO4 in the degradation of Rhodamineâ B. The enhanced performance is attributed to the carbon shells that restrict the growth of BiVO4 , the reduced graphene oxide that improves the electronic conductivity of the composite, and importantly, the bonds formed between the carbon shells and RGO that reduce the recombination loss of photogenerated charges effectively. The strategy is simple, effective, and can be extended to other ternary oxides with controlled size and high performance.
Assuntos
Bismuto , Grafite , Nanopartículas , Óxidos , Vanadatos , Bismuto/química , Bismuto/efeitos da radiação , Catálise , Glicerol/química , Grafite/química , Grafite/efeitos da radiação , Luz , Nanopartículas/química , Nanopartículas/efeitos da radiação , Oxirredução , Óxidos/química , Óxidos/efeitos da radiação , Processos Fotoquímicos , Rodaminas/química , Vanadatos/química , Vanadatos/efeitos da radiaçãoRESUMO
Device-related infections have been a big problem for a long time. This paper describes a new method to inhibit bacterial growth on implanted device with tissue-penetrating X-ray radiation, where a thin metallic film deposited on the device is used as a radio-sensitizing film for bacterial inhibition. At a given dose of X-ray, the bacterial viability decreases as the thickness of metal film (bismuth) increases. The bacterial viability decreases with X-ray dose increases. At X-ray dose of 2.5 Gy, 98% of bacteria on 10 nm thick bismuth film are killed; while it is only 25% of bacteria are killed on the bare petri dish. The same dose of X-ray kills 8% fibroblast cells that are within a short distance from bismuth film (4 mm). These results suggest that penetrating X-rays can kill bacteria on bismuth thin film deposited on surface of implant device efficiently.
Assuntos
Bismuto/farmacologia , Materiais Revestidos Biocompatíveis/química , Próteses e Implantes/microbiologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Esterilização/métodos , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/efeitos da radiação , Bismuto/química , Bismuto/efeitos da radiação , Proliferação de Células/fisiologia , Proliferação de Células/efeitos da radiação , Materiais Revestidos Biocompatíveis/efeitos da radiação , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos da radiação , Raios XRESUMO
We produced (211)At by irradiating the semi-sealed encapsulated Bi target with an external vertical beam. At 28.5MeV, the yield of (211)At was 22MBq/µAh (600µCi/µAh). (211)At was recovered by dry distillation, and 80% of the produced (211)At was successfully obtained in dry Na(211)At form within 2h from the end of bombardment (EOB). The radionuclidic purity of (211)At was >99% at 5h from EOB.
Assuntos
Astato/química , Astato/efeitos da radiação , Bismuto/química , Bismuto/efeitos da radiação , Íons Pesados , Compostos Radiofarmacêuticos/síntese química , Astato/isolamento & purificação , Marcação por Isótopo , Compostos Radiofarmacêuticos/efeitos da radiaçãoRESUMO
This paper presents first-principle studies on the photoelectric properties of various Bi2O3 polymorphs. The intrinsic reason of different photocatalytic activities was revealed by electronic structures and optical features. Results showed that for α, ß, and γ-Bi2O3, the top of valence bands were mainly constructed by Bi6s and O2p orbitals, and the bottom of conduction bands were dominantly composed by Bi6p orbital. However, two intermediate bands were found at the Fermi level for γ-Bi2O3, which leads to a two-step transition from the top of valence band to the bottom of conduction band and facilitates electron transition under irradiation. Absent forbidden gap was found in δ-Bi2O3, resulting in a semimetallic character due to its intrinsic oxygen vacancy and high ionic conductivity. Moreover, the optical properties of α, ß, and γ-Bi2O3 were investigated by absorption spectrum, dielectric constant function, and energy loss spectroscopy. We concluded that the photocatalytic activities followed in the order of γ-Bi2O3 > ß-Bi2O3 > α-Bi2O3, in accord with the experimental report. Calculation results illustrated the experimental observations and provided a useful guidance in exploring promising visible-light semiconductor photocatalysts.
Assuntos
Bismuto/efeitos da radiação , Simulação por Computador , Luz , Modelos Químicos , Modelos Moleculares , Processos Fotoquímicos , Semicondutores , Bismuto/química , Catálise , Cristalização , Espectroscopia Dielétrica , Elétrons , Transferência de Energia , Estrutura Molecular , Óptica e Fotônica , Relação Estrutura-AtividadeRESUMO
A phase junction over a Bi(2)SiO(5) photocatalyst with the orthorhombic Bi(2)SiO(5) and the tetragonal Bi(2)SiO(5) structure was successfully synthesized via an ion exchange method using BiOBr solid microspheres as the sacrificial template. In the meantime, the as-prepared Bi(2)SiO(5) phase junction possesses a novel morphology of a flower-like microsphere with nanoparticles evenly embedded in its nano-petals. It was found that the Bi(2)SiO(5) phase junction not only showed a highly enhanced photocatalytic activity and excellent durability under UV or simulated solar irradiation, but also showed a remarkable visible-light activity for photo-degradation of phenol. Experimental results reveal that the tetragonal Bi(2)SiO(5) phase in this phase junction possesses a narrower band gap, thus leading to its extended light absorption. The efficient charge separation via a phase junction would make a great contribution to its highly enhanced photocatalytic activity under UV or simulated solar irradiation. The high efficiency in the degradation of organic pollutants makes the as-prepared photocatalyst a promising candidate for photocatalytic environmental purification.
Assuntos
Bismuto/química , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Fenol/química , Sulfetos/química , Poluentes Químicos da Água/química , Bismuto/efeitos da radiação , Catálise , Luz , Teste de Materiais , Nanopartículas Metálicas/efeitos da radiação , Microesferas , Tamanho da Partícula , Fenol/efeitos da radiação , Fotoquímica/métodos , Sulfetos/efeitos da radiação , Raios Ultravioleta , Poluentes Químicos da Água/efeitos da radiação , Purificação da Água/métodosRESUMO
We report enhanced green and red upconversion (UC) luminescence in Ho3+-doped oxyfluoride germanate glass by introducing bismuth near-infrared active centers as sensitizers. The UC excitation bands at 750 and 970 nm show a full width at half-maximum of 20 and 45 nm, respectively. Energy transfer from sensitizers, the excited-state absorption, and phonon-coupled absorption of Ho3+ jointly contribute to the enhanced UC luminescence. Our approach provides an efficient methodology to broaden the excitation bandwidth of UC luminescent materials, which may have the potential for promising application in solar cells.
Assuntos
Bismuto/química , Vidro/química , Hólmio/química , Iluminação/instrumentação , Medições Luminescentes/instrumentação , Bismuto/efeitos da radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Vidro/efeitos da radiação , Hólmio/efeitos da radiação , Teste de MateriaisRESUMO
INTRODUCTION: The purpose of this study was to evaluate the effects of ultrasonic activation on the filling quality (intratubular sealer penetration, interfacial adaptation, and presence of voids) of 4 epoxy resin-based sealers. METHODS: Eighty-four extracted human canines were divided into 4 groups (n = 20) according to the sealer used to obturate the root canals instrumented with F5 ProTaper instruments (50/05) (Dentsply Maillefer, Ballaigues, Switzerland). The canals were filled by the lateral compaction technique. Previously, the sealers were labeled with rhodamine B dye to allow analysis under a confocal microscope. At the time of obturation, the specimens were divided again into 2 groups (n = 10) according to the ultrasonic activation of the sealers: ultrasonically activated and nonultrasonically activated groups. All samples were sectioned at 2, 4, and 6 mm from the apex. The percentages of voids, gaps, and dentinal sealer penetration segments of the canal were analyzed. RESULTS: Regarding the sealer penetration segments, there was a significant increase for the AH Plus (Dentsply Maillefer), Acroseal (Specialités Septodont, Saint Maur-des-Fossés, France), and Sealer 26 (Dentsply Maillefer) at the 4-mm level and the AH Plus and Sealer 26 at the 6-mm level with ultrasonic activation (P < .05). Concerning the gaps, the ultrasonic activation promoted a smaller presence for all sealers at the 4- and 6-mm levels (P < .05). No statistical significant differences were found for the percentages of voids (P < .05). CONCLUSIONS: The use of ultrasonic activation of an epoxy resin-based sealer promoted greater dentinal sealer penetration and less presence of gaps.
Assuntos
Resinas Epóxi/efeitos da radiação , Materiais Restauradores do Canal Radicular/efeitos da radiação , Ondas Ultrassônicas , Bismuto/química , Bismuto/efeitos da radiação , Hidróxido de Cálcio/química , Hidróxido de Cálcio/efeitos da radiação , Adaptação Marginal Dentária , Dentina/ultraestrutura , Resinas Epóxi/química , Corantes Fluorescentes , Humanos , Teste de Materiais , Microscopia Confocal , Porosidade , Rodaminas , Materiais Restauradores do Canal Radicular/química , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/instrumentação , Propriedades de Superfície , Ápice Dentário/ultraestruturaRESUMO
BiOBr/Na-montmorillonite composites (BiOBr-Mt) were prepared under laboratory ambient conditions by using the surfactant cetyltrimethylammonium bromide (CTAB) as the Br source and template, and the as-synthesized samples were characterized by XRD, FT-IR, FESEM, TEM equipped with EDS, BET and UV-vis DRS techniques. Interestingly, the particle size of BiOBr can be controlled by CTAB modified Na-montmorillonite. The photocatalytic activity of the as-prepared was further evaluated by decomposition of Rhodamine B (RhB) under visible light irradiation; the obtained results revealed that the BiOBr-Mt sample had strong photoabsorption in the visible light region. It has higher photocatalytic activity than pure BiOBr alone. There exists an efficient adsorption for RhB onto BiOBr-Mt contrast to that onto the pure BiOBr. The adsorption processes can be well described by pseudo-second-order kinetic model; meanwhile, the adsorption behaviors can be described by both Freundlich and Langmuir equations but the former was better. Additionally, the relevant adsorption and degradation mechanisms were explored and the possible mechanisms were presented. The photocatalytic activity has high effect both in acidic and basic conditions on the degradation reaction but in acidic condition is more favorable. After three recycles, BiOBr-Mt did not exhibit any significant loss of photocatalytic activity, confirming the photocatalyst was essentially stable.
Assuntos
Bentonita/química , Bismuto/química , Corantes Fluorescentes/química , Luz , Rodaminas/química , Poluentes Químicos da Água/química , Adsorção , Bismuto/efeitos da radiação , Catálise , Cetrimônio , Compostos de Cetrimônio/química , Processos Fotoquímicos , Eliminação de Resíduos Líquidos/métodosRESUMO
AgCl/BiOCl heteronanostructures were synthesized by a room-temperature chemical coprecipitation method. The as-obtained products were characterized by energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis diffuse spectra, which show the structures, morphologies, and optical properties. The results revealed that the absorption edge of AgCl/BiOCl shifted towards visible light regions. Meanwhile, the AgCl/BiOCl heteronanostructures showed better photocatalytic properties than the pure BiOCl to degrade rhodamine B and the 5% AgCl/BiOCl showed the best photocatalytic ability, which completely decomposed the target molecules in 17 minites with the visible-light illumination. The formation of heteronanostructures might improve the separation of photogenerated electrons and holes derived from the coupling effect of BiOCl and AgCl heteroarchitectures, which was regarded as the main reason for the high photocatalytic activity.
Assuntos
Bismuto/química , Cristalização/métodos , Precipitação Fracionada/métodos , Nanoestruturas/química , Fotoquímica/métodos , Rodaminas/química , Compostos de Prata/química , Bismuto/efeitos da radiação , Catálise/efeitos da radiação , Luz , Teste de Materiais , Nanoestruturas/efeitos da radiação , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Rodaminas/efeitos da radiação , Compostos de Prata/efeitos da radiaçãoRESUMO
Monoclinic BiVO4 nano- and microstructures with a diversity of well-defined morphologies, such as nanoplates, dendrite leaves-like structures, sub-microrods, and microflowers were synthesized via a template-free hydrothermal process with bismuth nitrate and ammonium metavanadate as metal source. The crystal structures, morphologies and optical properties of the as-prepared samples were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectra (UV-vis). Results showed that the pH value of the solution and the volume of ethylenediamine have great effect on the formation of these unique structures. The photocatalytic activity of these as-prepared samples had been tested by degradation of methylene blue under visible light, indicating that showed good photocatalytic performance.
Assuntos
Bismuto/química , Azul de Metileno/química , Impressão Molecular/métodos , Nanoestruturas/química , Fotoquímica/métodos , Vanadatos/química , Água/química , Bismuto/efeitos da radiação , Catálise/efeitos da radiação , Cristalização/métodos , Temperatura Alta , Luz , Teste de Materiais , Azul de Metileno/efeitos da radiação , Nanoestruturas/efeitos da radiação , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Doses de Radiação , Vanadatos/efeitos da radiaçãoRESUMO
In order to measure the spatial distributions of neutrons and gamma rays separately using the imaging plate, the requirement for the converter to enhance specific component was investigated with the PHITS code. Consequently, enhancing fast neutrons using recoil protons from epoxy resin was not effective due to high sensitivity of the imaging plate to gamma rays. However, the converter of epoxy resin doped with (10)B was found to have potential for thermal and epithermal neutrons, and graphite for gamma rays.
Assuntos
Bismuto/química , Terapia por Captura de Nêutron de Boro/instrumentação , Boro/efeitos da radiação , Resinas Epóxi/química , Raios gama , Nêutrons , Radiometria/instrumentação , Materiais Restauradores do Canal Radicular/química , Prata/química , Titânio/química , Bismuto/efeitos da radiação , Boro/química , Resinas Epóxi/efeitos da radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Isótopos/química , Isótopos/efeitos da radiação , Dosagem Radioterapêutica , Materiais Restauradores do Canal Radicular/efeitos da radiação , Espalhamento de Radiação , Prata/efeitos da radiação , Análise Espaço-Temporal , Titânio/efeitos da radiaçãoRESUMO
We report the cw-laser-induced oxidation of molecular-beam-epitaxy grown GaAsBi bismuth surface microdroplets investigated in situ by micro-Raman spectroscopy under ambient conditions as a function of irradiation power and time. Our results reveal the surface droplets are high-purity crystalline bismuth and the resultant Bi2O3 transformation to be ß-phase and stable at room temperature. A detailed Raman study of Bi microdroplet oxidation kinetics yields insights into the laser-induced oxidation process and offers useful real-time diagnostics. The temporal evolution of new ß-Bi2O3 Raman modes is shown to be well described by Johnson-Mehl-Avrami-Kolmogorov kinetic transformation theory and while this study limits itself to the laser-induced oxidation of GaAsBi bismuth surface droplets, the results will find application within the wider context of bismuth laser-induced oxidation and direct Raman laser processing.
Assuntos
Arsenicais/química , Bismuto/química , Cristalização/métodos , Gálio/química , Lasers , Análise Espectral Raman/métodos , Arsenicais/efeitos da radiação , Bismuto/efeitos da radiação , Gálio/efeitos da radiação , Teste de Materiais , Oxirredução/efeitos da radiação , Doses de Radiação , Soluções , Propriedades de Superfície/efeitos da radiaçãoRESUMO
Well-defined, uniform bismuth vanadate (BiVO4) microcolumns were synthesized through a refined hydrothermal route. During the fabrication process, a detailed orthogonal design on the synthetic conditions was performed, aiming to optimize the experimental parameters to produce BiVO4 materials (BiVO4 (Opt.)) with the most prominent visible-light-driven photocatalytic efficiency, where the catalytic activities of the synthesized materials were evaluated via the decolorization of methylene blue under visible light irradiation. The BiVO4 (Opt.) were then targetedly produced according to the determined optimal conditions and well characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet and visible diffuse-reflectance spectroscopy and photoluminescence spectroscopy. Compared with the commercial P25-TiO2 photocatalysts, the as-synthesized BiVO4 (Opt.) displayed superior visible-light-driven photocatalytic activities for the degradation of metronidazole-contained wastewater with the presence of H2O2. The degradation efficiency of metronidazole reached up to 70 % within 180 min, leading to a brief speculation on the possibly major steps of the visible-light-driven photocatalytic process. The current study provides a distinctive route to design novel shaped BiVO4 architectures with advanced photocatalytic capacities for the treatment of organic pollutants in the aqueous environment.
Assuntos
Bismuto/química , Metronidazol/química , Vanadatos/química , Poluentes Químicos da Água/química , Bismuto/efeitos da radiação , Catálise , Corantes/química , Luz , Azul de Metileno/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Fotólise , Vanadatos/efeitos da radiação , Águas Residuárias , Difração de Raios XRESUMO
A series of graphene sheets grafted three-dimensional BiOBr0.2I0.8 microspheres with different graphene contents have been synthesized by a simple one-step solvothermal method. The BiOBr0.2I0.8 microspheres were composed of numerous nanoplates with a thickness of about 10nm and dispersed uniformly on the surface of graphene. The assembled BiOBr0.2I0.8/graphene composites exhibited excellent photocatalytic activity in the degradation of rhodamine B (RhB) and phenol under visible light irradiation (λ>420 nm). The optimal graphene content was found to be 10.0 wt.%, and the corresponding photocatalytic activity in degradation of RhB and phenol was 3.19 and 3.27 times that of pure BiOBr0.2I0.8, respectively. The enhanced photocatalytic activity could be attributed to more effective charge transportations and separations, larger specific surface areas and the increased light absorption. A possible photocatalytic mechanism of the BiOBr0.2I0.8/graphene composites was also proposed.
Assuntos
Bismuto/química , Bismuto/efeitos da radiação , Grafite/química , Grafite/efeitos da radiação , Luz , Poluentes Químicos da Água/química , Catálise , Microesferas , Fenol/química , Fotólise , Rodaminas/químicaRESUMO
Photocatalytic degradation of sulfamethoxazole (SMX) was investigated using Bi2O3/Bi2O2CO3/Sr6Bi2O9 (BSO) photocatalyst under visible light (>420 nm) irradiation. The photochemical degradation of SMX followed pseudo-first-order kinetics. The reaction kinetics was determined as a function of initial SMX concentrations (5-20 mg L(-1)), initial pH (3-11) and BSO concentrations (6-600 mg L(-1)). Approximately, 90% of SMX (10 mg L(-1)) degradation and 36% of TOC reduction were achieved at pH 7.0 after 120 min irradiation. The main mineralization products, including NH4(+), NO3(-), SO4(2-) and CO2, as well as intermediates 3-amino-5-methylisoxazole (AMI), p-benzoquinone (BZQ), and sulfanilic acid (SNA) were detected in aqueous solution. The formation of O2(*-) radical was evidenced by using electron spin resonance and a chemiluminescent probe, luminal. A possible degradation mechanism involving excitation of BSO, followed by charge injection into the BSO conduction band and formation of reactive superoxide radical (O2(*-)) was proposed for the mineralization of SMX. During the reaction, the O2(*-) radical attacks the sulfone moiety and causes the cleavage of the SN bond, which leads to the formation of two sub-structure analogs, AMI and SNA.
Assuntos
Bismuto/química , Sulfametoxazol/química , Superóxidos/química , Poluentes Químicos da Água/química , Antibacterianos/química , Bismuto/efeitos da radiação , Catálise , Luz , Processos Fotoquímicos , Purificação da Água/métodosRESUMO
Eu-B co-doped BiVO4 visible-light-driven photocatalysts have been synthesized using the sol-gel method. The resulting materials were characterized by a series of joint techniques, including XPS, XRD, SEM, BET, and UV-vis DRS analyses. Compared with BiVO4 and B-BiVO4 photocatalysts, the Eu-B-BiVO4 photocatalysts exhibited much higher photocatalytic activity for methyl orange (MO) degradation under visible light irradiation. The optimal Eu doping content is 0.8 mol%. It was revealed that boron and europium were doped into the lattice of BiVO4 and this led to more surface oxygen vacancies, high specific surface areas, small crystallite size, a narrower band gap and intense light absorbance in the visible region. The doped Eu(III) cations can help in the separation of photogenerated electrons. The synergistic effects of boron and europium in doped BiVO4 were the main reason for improving visible light photocatalytic activity.
Assuntos
Compostos Azo/química , Bismuto/química , Boro/química , Európio/química , Nanopartículas/química , Vanadatos/química , Poluentes Químicos da Água/química , Bismuto/efeitos da radiação , Boro/efeitos da radiação , Európio/efeitos da radiação , Luz , Microscopia Eletrônica de Varredura , Nanopartículas/efeitos da radiação , Nanopartículas/ultraestrutura , Fotólise , Vanadatos/efeitos da radiaçãoRESUMO
Bi2O3 was successfully synthesized via microwave-assisted reaction of Bi2O3 precursor in aqueous solution using a microwave system. Their morphologies, structures and photocatalytic performances in the degradation of methylene blue (MB) were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, photoluminescence spectroscopy and UV-vis absorption spectroscopy, respectively. The results show that Bi2O3 synthesized at pH value of 7 exhibits an optimal photocatalytic performance with the MB degradation rate of 76% at 240 min under visible light irradiation due to its higher visible light absorption and comparatively low electron-hole pair recombination.