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1 – 10 of 213Dong Chen, Rui Zhang and JiaCheng Jiang
This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of…
Abstract
Purpose
This study aims to investigate the morphology and physicochemical properties of BiOBr/Polyvinylidene fluoride (PVDF) composite membranes and the differences in the properties of BiOBr/PVDF composite membranes made by adding different precursor ratios during the casting process.
Design/methodology/approach
In this paper, sodium bromide and Bi(NO3)3 were used as precursors for the preparation of BiOBr photocatalysts, and PVDF membranes were modified by using the phase conversion method in conjunction with the in situ deposition method to produce BiOBr/PVDF hydrophilic composite membranes with both membrane separation and photocatalytic capabilities.
Findings
The characterization results confirmed that the composites were successfully and homogeneously co-mingled in the PVDF membranes. The related performance of the composite membrane was tested, and it was found that the composite membrane with the optimal precursor incorporation ratio had good photocatalytic efficiency and antipollution ability; the removal efficiencies of methyl orange, rhodamine B and methylene blue were 80.43%, 85.02% and 86.94%, respectively, in 2.5 h. The photocatalytic efficiency of composite membranes with different precursor ratios increased and then decreased with the increase of the precursor addition ratio.
Originality/value
The composite membrane is prepared by phase conversion method with in situ deposition method, and the BiOBr material has unique advantages for the degradation of organic dyes. The comprehensive experimental data can be known that the composite membrane prepared in this paper has high degradation efficiency and good durability for organic dyes.
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Abstract
Purpose
The aim of this paper is to synthesize graphene-modified titanium dioxide (GR-TiO2) nanorod arrays nanocomposite films, so that these can enhance the photocatalytic properties of titanium dioxide and overcome the problem of difficult separation and recovery of photocatalysts.
Design/methodology/approach
The GR-TiO2 nanocomposite films were synthesized via hydrothermal method and spin-coating. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), ultraviolet–visible (UV-Vis) diffuse reflectance spectrum and Raman spectrum. The photocatalytic performance of the GR-TiO2 nanocomposite films for degrading Rhodamin B under ultraviolet (UV) was studied by a UV-Vis spectrophotometer. The photocatalytic enhancement mechanism of graphene was studied by photoelectrochemical analysis.
Findings
The introduction of graphene expanded the range of the optical response of TiO2 nanorod arrays, improving the separation efficiency of the photogenerated electron-hole pairs, and thus dramatically increasing its photocatalytic performance.
Research limitations/implications
A simple and novel way for synthesizing GR-TiO2 nanocomposite films has enhanced the photocatalytic performance of TiO2.
Originality/value
The photocatalyst synthesized is easy to separate and recycle in the process of photocatalytic reaction, so it is possible to achieve industrialization.
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Abstract
Purpose
The purpose of this paper is to provide an investigation on a new kind of photocatalytic material, namely, the porous ceramic foam loading titanium dioxide, which can make an effective photocatalytic degradation of the methyl orange (MO) solution in the wastewater.
Design/methodology/approach
The natural zeolite powder has been used as the primary raw material to produce a sort of lightweight porous ceramic foam by impregnating polymer foam in slurry and then sintering. With the sol-gel method, a kind of open-cell reticular porous ceramic foam loading TiO2 film was obtained having a good photocatalytic action, and the resultant porous composite product presents the bulk density of 0.3~0.6 g/cm3 to be able to float on water.
Findings
The MO could tend to be completely degraded in the solution with a certain concentration by the TiO2-loaded ceramic foam irradiated with ultraviolet light, and this composite foam was found to have high degradation efficiency for the MO solution in a wide range of pH.
Originality/value
This work presents a TiO2-loaded ceramic foam that can effectively photo-catalyze to degrade the MO in water, and the degradation efficiency were examined under different conditions of the MO solution with various pH values.
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This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).
Abstract
Purpose
This paper aims to investigate the reusability of metal/metal oxide-coupled ZnO nanorods (ZnO NRs) to degrade rhodamine B (RhB).
Design/methodology/approach
ZnO NRs particles were synthesized by precipitation method and used to remove various types of metal ions such as Cu2+, Ag+, Mn2+, Ni2+, Pb2+, Cd2+ and Cr2+ ions under UV illumination. The metal/metal oxide-coupled ZnO NRs were characterized by scanning electron microscope, X-ray diffraction and UV-Vis diffuse reflectance. The photodegradation of RhB dye by these metal/metal oxide-coupled ZnO NRs under UV exposure was assessed.
Findings
The metal/metal oxide-coupled ZnO NRs were successfully reused to remove RhB dye in which more than >90% of RhB dye was degraded under UV exposure. Furthermore, the coupling of Ag, CuO, MnO2, Cd and Ni particles onto the surface of ZnO NRs even enhanced the degradation of dye. The dominant reactive species involved in the degradation of RhB dye were •OH- and •O2−-free radicals.
Research limitations/implications
The coupling of metal/metal oxide onto the surface of ZnO NRs after metal ions removal could affect the photocatalytic performance of ZnO NRs in the degradation of organic pollutants in subsequent stage.
Practical implications
A good reusability performance of metal/metal oxide-coupled ZnO NRs make ZnO NRs become a desirable photocatalyst material for the treatment of wastewater, which consists of both heavy metal ions and organic dyes.
Originality/value
Metal/metal oxide coupling onto the surface of ZnO NRs particles improved subsequent UV-assisted photocatalytic degradation of RhB dye.
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Mei Yang, Tingyu Huang, Ning Tang, Ben Ou and Wenhao Zhang
This paper aims to investigate the photocatalytic activity of zinc doped MAO-TiO2 films under the optimum MAO treatment condition.
Abstract
Purpose
This paper aims to investigate the photocatalytic activity of zinc doped MAO-TiO2 films under the optimum MAO treatment condition.
Design/methodology/approach
The coating was prepared by micro arc oxidation, and the influence of doping on the properties of the coating was also investigated.
Findings
The results show that the BET surface area is 78.25±0.03m2/g, total pore area is 76.32 ± 0.04m2/g, and the total pore volume is 0.2135 ± 0.0004cm3/g. The degradation ratio of the film electrode with Zn-doped in methyl orange solution is up to 94%. When the react circles is 10 times, the degradation ratio is up to more than 85% and remains steady. With the different reaction conditions, these kinetics of the reactions show some different formulas.
Originality/value
A kinetic equation for photocatalytic activity is established.
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Wenjie Wang, Mengran Zhang, Binxia Zhao, Linxue Liu, Ruixuan Han and Nan Wang
The purpose of this paper is to improve the degradation efficiency of Rhodamine B (RhB) by new photocatalytic materials.
Abstract
Purpose
The purpose of this paper is to improve the degradation efficiency of Rhodamine B (RhB) by new photocatalytic materials.
Design/methodology/approach
Binary Z-scheme g-C3N4/Bi2WO6 photocatalytic material was synthesized by the one-step hydrothermal reaction. The construction of Z-scheme heterojunction led to the rapid separation of photogenerated electrons and holes, which would degrade RhB into small molecular substances to achieve the purpose of degradation.
Findings
It was found that Bi2WO6/25%g-C3N4 displayed the highest photocatalytic activity, which was about 1.44 and 1.34 times higher than that of pure Bi2WO6 and g-C3N4, respectively. According to the trapping experiments, the superoxide radical (·O2−) was the major active species of the RhB decomposition in Bi2WO6/g-C3N4 catalysts.
Originality/value
The successful synthesis of Z-scheme Bi2WO6/g-C3N4 provides new ideas and references for the design of catalysts with high photocatalytic activity, which should have wide applications in the future.
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Juan Xie, Meixia Li, Yongjing Hao, Xiaocai Meng, Yuan Meng and Zhen Li
Using only zinc nitrate, ferric nitrate and sodium hydroxide as reactants, rod-like and flower-like α-Fe2O3/ZnO composites were prepared via a simple and rapid solution route by…
Abstract
Using only zinc nitrate, ferric nitrate and sodium hydroxide as reactants, rod-like and flower-like α-Fe2O3/ZnO composites were prepared via a simple and rapid solution route by controlling the composition of precursor solution. The products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-vis diffuse reflectance spectra (UV-vis DRS). Photocatalytic activity of the as-prepared α-Fe2O3/ZnO composites was evaluated by degradation of methyl orange (MO) under simulated solar light. The results indicated that both α-Fe2O3/ZnO composites possess higher photocatalytic activity than commercial P25 TiO2. In addition, possible reasons why α-Fe2O3/ZnO composites have excellent photocatalytic performance were discussed.
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Saadet Güler, Ahmet Yavaş, Berk Özler and Ahmet Çagri Kilinç
Three-dimensional (3D) printing is popular for many applications including the production of photocatalysts. This paper aims to focus on developing of 3D-printed…
Abstract
Purpose
Three-dimensional (3D) printing is popular for many applications including the production of photocatalysts. This paper aims to focus on developing of 3D-printed photocatalyst-nano composite lattice structure. Digital light processing (DLP) 3D printing of photocatalyst composites was performed using photosensitive resin mixed with 0.5% Wt. of TiO2 powder and varying amounts (0.025% Wt. to 0.2% Wt.) of graphene nanoplatelet powder. The photocatalytic efficiency of DLP 3D-printed photocatalyst TiO2 composite was investigated, and the effects of nano graphite powder incorporation on the photocatalytic activity, thermal and mechanical properties were investigated.
Design/methodology/approach
Methods involve 3D computer-aided design modeling, printing parameters and comprehensive characterization techniques such as structural equation modeling, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared (FTIR) and mechanical testing.
Findings
Results highlight successful dispersion and characteristics of TiO2 and graphene nanoplatelet (GNP) powders, intricate designs of 3D-printed lattice structures, and the influence of GNPs on thermal behavior and mechanical properties.
Originality/value
The study suggests applicability in wastewater treatment and environmental remediation, showcasing the adaptability of 3 D printing in designing effective photocatalysts. Future research should focus on practical applications and the long-term durability of these 3D-printed composites.
Graphical abstract
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Juan Xie, Yongjing Hao, Meixia Li, Yiwei Lian and Li Bian
This paper aims to report a novel preparation method of titanium dioxide (TiO2)/zinc oxide (ZnO) composites with different mole ratios of TiO2:ZnO and their photocatalytic…
Abstract
Purpose
This paper aims to report a novel preparation method of titanium dioxide (TiO2)/zinc oxide (ZnO) composites with different mole ratios of TiO2:ZnO and their photocatalytic activity.
Design/methodology/approach
TiO2/ZnO composites are prepared by a facile route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultra-violet–visible diffuse reflectance spectra (UV-vis DRS) are used to characterize the products. Photocatalytic activity of the samples is evaluated by degradation of persistent organic pollutant pentachlorophenol under ultra-violet (UV) irradiation.
Findings
It is found that all the as-prepared TiO2/ZnO composites not only have good catalytic activity under UV light irradiation, but also have excellent circulation stability. The optimal mole ratio of TiO2:ZnO is 0.75:1.
Originality/value
This report presents a simple and rapid method for the preparation of TiO2/ZnO composites with excellent photocatalytic activity. Experimental results could provide useful reference for the treatment of chlorophenols in the future.
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M. Rashidzadeh, B. Faridnia and M.R. Ghasemi
The purpose of this paper is to study the effect of synthesis conditions on properties of TiO2 nanoparticles to be used for photocatalysis and also producing TiO2 using a low…
Abstract
Purpose
The purpose of this paper is to study the effect of synthesis conditions on properties of TiO2 nanoparticles to be used for photocatalysis and also producing TiO2 using a low temperature method.
Design/methodology/approach
TiO2 nanoparticles were synthesised via a sol‐gel method at low temperature and the effect of parameters such as: synthesis temperature, HNO3 concentration, calcination temperature and synthesis time on properties of TiO2 were studied. The effects of the physico‐chemical properties of TiO2, its concentration and light intensity on photocatalytic properties of TiO2 nanoparticles were investigated also.
Findings
The results showed that TiO2 with Anatase phase were formed at 80‐100°C by using proper HNO3 concentration, synthesis time and calcinations temperature. Calcinations programme and temperature and also the synthesis time affect the formation of TiO2 crystalline phase (i.e. Rutile and Brookite), their surface area and crystallite size. To evaluate the photocatalytic properties of TiO2 nanoparticles, fluorescein was used as a model molecule. Results showed that degradation of fluorescein could be described by pseudo‐first order kinetics. The effect of TiO2 concentration and light intensity on photocatalytic activity showed that increasing concentration of TiO2 and the light intensity would increase the degradation of fluorescein.
Originality/value
The method used in this work to prepare TiO2 nanoparticles is an economic method for low temperature synthesis of TiO2 nanoparticles with high photocatalytic activity, which could find numerous applications in coating technology.
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