Mehrdad Hajian; Mohammad Rostamizadeh; Federico Galli
Abstract
Catalysis for environmental remediation is becoming of paramount importance as industrial and urban activities multiply, and by-products contaminate soils and wastewater. Effluents from industrial and urban activities have led to many environmental problems involving water contamination. Here, we propose ...
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Catalysis for environmental remediation is becoming of paramount importance as industrial and urban activities multiply, and by-products contaminate soils and wastewater. Effluents from industrial and urban activities have led to many environmental problems involving water contamination. Here, we propose a new iron-incorporated metal-organic framework (MOF) photocatalyst to decontaminate water. The nanocatalyst was synthesized by the solvothermal method, and Fe was added to the structure as a promoter and active phase. In this study, we examined the degradation of methylene blue (MB) as a cationic azo dye. The nanocatalysts were characterized by XRD, FE-SEM, BET, NH3-TPD, and FTIR techniques. The results showed high crystallinity, a large specific surface area, and a uniform promoter distribution. At a pH = 9, a catalyst amount of 110 mg and an initial MB concentration in the effluent of 2 ppm resulted in the highest removal percentage (98 %). The kinetic analysis provided a quasi-first-order model that reasonably matched the experimental data (R2 = 95 %). The results verified the catalyst’s great capability for efficient and fast MB removal in 60 minutes of photocatalytic processing.
Hassanali Rasouli; Faezeh Jafarpisheh; Mohammad Ghorbanpour
Abstract
Dyes are produced as water pollutants in the textile, plastic, and dye industries. Many efforts have been made to remove dyes from industrial wastewater. In this area, Photocatalytic performance under Vis-lights is a useful and effective method. In this study, a series of highly efficient Sn-doped TiO2 ...
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Dyes are produced as water pollutants in the textile, plastic, and dye industries. Many efforts have been made to remove dyes from industrial wastewater. In this area, Photocatalytic performance under Vis-lights is a useful and effective method. In this study, a series of highly efficient Sn-doped TiO2 photocatalysts were successfully developed using a simple heat treatment process. Three concentrations of SnCl2 powder (3%, 5%, and 7 %) were used for the preparation of materials. The characterizations of resulting materials were distinguished by scanning electron microscopy (SEM), diffusion reflection spectroscopy (DRS), and X-ray diffraction spectroscopy (EDX). Also, methyl orange dye was served to indicate the photocatalytic activity of Sn-doped material under visible light irradiation. The results indicated that both doped and also pure TiO2 have a uniform size. Anatase was the only identified phase in all the products, whether doped or un-doped. The resulting Sn-doped materials have demonstrated a band gap value range of 3.14 to 2.68 eV in comparison with pure TiO2 which shows a value of 3.2 eV. The photocatalytic evaluations indicated that the samples prepared in the presence of 3, 5, and 7% SnCl2 have degradation efficiencies of 85%, 85%, and 90%, respectively within 120 min, which are much higher than that of un-doped TiO2. The enhancement in the efficiency was attributed to the gap changes in anatase by the incorporation of Sn ions into the TiO2 lattice structure. Compared to pure TiO2, which has a band gap of 3.2 eV, the band gap values for doped TiO2 ranged from 3.14 to 2.68 eV.
Ghader Hosseinzadeh
Abstract
In the current study, for the first time, an innovative hydrothermal method was proposed for the synthesis of TiO2/WO3 heterojunction nanocomposite from the combination of TiO2 nanorod, and WO3 nanoflakes. Because of environmental issues arising from the vast use of insecticides, this nanocomposite photocatalyst ...
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In the current study, for the first time, an innovative hydrothermal method was proposed for the synthesis of TiO2/WO3 heterojunction nanocomposite from the combination of TiO2 nanorod, and WO3 nanoflakes. Because of environmental issues arising from the vast use of insecticides, this nanocomposite photocatalyst was applied for the first time for photocatalytic degradation of Nitenpyram insecticide under visible light irradiation. The prepared nanocomposite was fully characterized by XRD, FESEM, DRS, PL, and Mott-Schottky analysis. The results revealed that the heterojunction sample had the best photocatalytic performance. The enhanced photocatalytic activity of this heterojunction is attributed to the decrease of the charge carrier’s recombination rate and enhanced visible light harvesting. Moreover, based on the radical trapping experiments and Mott-Schottky calculations, hydroxide radical was determined as the main active species for decomposition of Nitenpyram insecticide, and type II charge transfer mechanism was revealed to be responsible for the enhanced photocatalytic performance, which charge transfer between the two semiconductors results in the decreasing of the charge carrier’s recombination rate.
Mahmood Hajiani; Efat Ezami; Mohammad Reza Rezaei
Abstract
Fe3O4/ ZnO/Ag magnetic nanocomposite was synthesized for the first time and its ability was evaluated for photocatalytic degradation of albumin in aqueous solutions under UV-A light. The resulting nanoparticles were then characterized using X-ray diffraction (XRD), scanning electron microscopy (FESEM), ...
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Fe3O4/ ZnO/Ag magnetic nanocomposite was synthesized for the first time and its ability was evaluated for photocatalytic degradation of albumin in aqueous solutions under UV-A light. The resulting nanoparticles were then characterized using X-ray diffraction (XRD), scanning electron microscopy (FESEM), vibration magnetometer (VSM), and Fourier infrared (FTIR). The effects of some parameters such as pH, initial albumin concentration, catalyst concentration, and temperature were also investigated in the photodegradation of albumin. The results showed that the maximum removal of albumin was obtained at pH 9, catalyst concentration of 0. 5 g/l, initial albumin concentration of 150 mg/l, and room temperature in 90 min. Under the optimum conditions, the total amount of organic carbon (TOC) was 56%. Kinetic degradation experiments followed the pseudo-first-order kinetic model with a constant rate (k) of 0.0255 min-1. Therefore, due to the high performance of Fe3O4/ ZnO/Ag magnetic nanocomposite in the degradation of albumin as well as its easy synthesis and separation with an external magnetic field, it can be used as a suitable and environmentally friendly catalyst for the degradation of organic and resistant pollutants in the wastewater.
D Kamarajan; Benny Anburaj; V Porkalai; A Muthuvel; G Nedunchezhian; N Mahendran
Abstract
The current study aimed to synthesize nanoparticles of Zinc oxide (ZnO) using the extract of Acalypha indica leaves and their photocatalyst degradation and antibacterial properties were also measured. The biosynthesized nanoparticles were analyzed using XRD, UV-visible, FT-IR, and SEM with EDAX, DLS, ...
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The current study aimed to synthesize nanoparticles of Zinc oxide (ZnO) using the extract of Acalypha indica leaves and their photocatalyst degradation and antibacterial properties were also measured. The biosynthesized nanoparticles were analyzed using XRD, UV-visible, FT-IR, and SEM with EDAX, DLS, PL, and Zeta potential analysis. The synthesized nanoparticles had a mean size of 16 nm measured by XRD which was highly pure, and their spherical shape was confirmed by SEM. The UV-visible confirmed that ZnO nanoparticles have a direct band gap energy is 3.34 eV. The measured zeta size and potential of synthesized nanoparticles were 46 nm and -27 mV, respectively, determined by the DLS technique can be considered moderately stable colloidal solutions. The FT-IR analysis confirmed the presence of functional groups in the leaf extract and the ZnO nanoparticles. The biosynthesized ZnO nanoparticles have a homogeneous spherical morphology and the average particle is 35 nm. The PL analyses performed on synthesized nanoparticles showed a sharp blue band at 362 nm, which was attributed to the defects of structure in ZnO crystals. During natural sunlight illumination, ZnO nanoparticles demonstrated notable degradation of the dye methyl blue (MB). At 90 min of illumination, the degradation efficiency achieved was 96 %. Antibacterial properties were observed for synthesized nanoparticles against four bacterial strains, including Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The highest zone of inhibition was observed against Escherichia coli (25.2 mm). Overall, these studies indicate that Acalypha indica is a good sell for planting, and has the greatest chance of being used to develop nanoparticles for protection against environmental pollution and human health.
Sankara Rao Miditana; Siva Rao Tirukkovalluri; Manga Raju Imandi; Bangaru Babu A; Ramesh Babu A
Abstract
TiO2-based nanomaterials are very effective for water and air purification and act as good antibacterial agents due to their unique physicochemical properties. TiO2 is a promising nanocatalyst because of its non-toxicity, chemical stability, and low cost. The wide band gap and rapid electron-hole recombination ...
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TiO2-based nanomaterials are very effective for water and air purification and act as good antibacterial agents due to their unique physicochemical properties. TiO2 is a promising nanocatalyst because of its non-toxicity, chemical stability, and low cost. The wide band gap and rapid electron-hole recombination limit its performance which can be overcome by doping with metals and non-metal ions. Metal doping improves the trapping of electrons to inhibit electron-hole recombination and non-metal doping reduces the bandgap of TiO2. These doped TiO2 materials can be synthesized by different routes like the Sol-gel method, hydrothermal method, precipitation method, impregnation method, etc. Among these, the Sol-gel method is reported as the best and most accurate for the synthesis of TiO2 particles in the nano scale range. Because it allows the incorporation of dopant ions at the molecular level with homogeneity and high chemical purity. The structural, morphological, and optical properties of as-synthesized TiO2 nanocatalysts can be well characterized by XRD, SEM, EDX, FT-IR, UV Vis-DRS, TEM, BET, and PL. In this review article, we would like to discuss the advantage of the Sol-gel method over other preparative methods of TiO2 nanomaterials and experimental techniques related to their characterization.
Jyoti A. Agashe; Dipak R. Tope; sachin S Kushare; Ashok V Borhade
Abstract
Nanocrystalline UV light induced composite CeO2:SiO2 with high surface area and low band gap energy were prepared in order to assess its photocatalytic degradation capacity of target pollutant (mixture of dyes). The complete mineralization of target dye pollutants (30 ppm) occurred within 150 min. when ...
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Nanocrystalline UV light induced composite CeO2:SiO2 with high surface area and low band gap energy were prepared in order to assess its photocatalytic degradation capacity of target pollutant (mixture of dyes). The complete mineralization of target dye pollutants (30 ppm) occurred within 150 min. when CeO2:SiO2 catalyst with optimum loading 0.4 g was used. Overall, the present system is economical, reproducible and highly efficient. Further the comparative study on photocatalytic efficiency of SiO2 and CeO2 was compared with composite CeO2:SiO2. The effect of various operational parameters used in degradation like concentration of dye, amount of photocatalyst and various catalyst has been studied on the rate of reaction. The recyclability of the photocatalyst, CeO2:SiO2 was performed up to four runs. The photodegradation of waste water pollutants was occurred nearly 96 % using CeO2:SiO2 nanoparticles. The removal of waste water pollutants was confirmed by UV spectrophotometer by diminishing the absorbance to zero within 120 min using CeO2:SiO2 nanoparticles. The synthesized catalyst was characterized by various analytical investigative techniques like UV-DRS, FTIR, XRD, SEM, TEM and BET.
Aiman M.A Noman; Mohammed A. Alghobar; Sidduraiah Suresha
Abstract
In this study, p-n junction photocatalyst CuO/CeO2ZrO2 with different concentrations of CuO was prepared by auto solution combustion method using glycine as fuel. This method is simple, fast and cost effective compared with other preparation methods. The photocatalyst was characterized by X-ray diffraction ...
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In this study, p-n junction photocatalyst CuO/CeO2ZrO2 with different concentrations of CuO was prepared by auto solution combustion method using glycine as fuel. This method is simple, fast and cost effective compared with other preparation methods. The photocatalyst was characterized by X-ray diffraction (XRD), energy-dispersive spectrometer (EDS), UV-vis DRS. The assembly of p-type CuO nanoparticles produces a large number of nano p–n junction heterostructures on the surface of the CeO2ZrO2 nanocrystals, where CuO and CeO2ZrO2 form p- and n-type semiconductors. The experimental results reveal that p–n junction CuO/CeO2-ZrO2 heterojunction nanostructures exhibit much higher visible-light photocatalytic activities than the n-CeO2-ZrO2 for the removal of dye from industerial waste water. The photocatalytic activity of the p-n CuO/CeO2-ZrO2 heterojunction photocatalyst was evaluated using the degradation of aqueous methylene blue solution (MB) under visible light irradiation(λ>420 nm). The photo-degradation rate of this catalyzed is much faster than those occurring on n-type CeO2ZrO2. The sample with a p-n CuO/ CeO2-ZrO2 molar ratio of 0.021 presented the best photocatalytic activity, which was 30% higher than that of n-type CeO2ZrO2. The heat treatment condition also influences the photocatalytic activity strongly, and the best preparation condition is about 400ºC for 4h.
Pijushkanti Purkait; Arijita Bhattacharyya; Sankhajit Roy; Saikat Maitra; Gopes Das; Mahua Ghosh Chaudhuri
Abstract
This article reports the green synthesis of titanium dioxide nanoparticles (TiO2 NPs) from aqueous leaf extract of Trema Orientalis (L) and its effectiveness in photodegradation process of zoxamide under UV irradiation(λ max ≥ 250 nm) . Titanium (IV) isopropoxide act as the precursor and leaf ...
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This article reports the green synthesis of titanium dioxide nanoparticles (TiO2 NPs) from aqueous leaf extract of Trema Orientalis (L) and its effectiveness in photodegradation process of zoxamide under UV irradiation(λ max ≥ 250 nm) . Titanium (IV) isopropoxide act as the precursor and leaf extract act as the reducing agent. The synthesized TiO2 NPs are confirmed by the powder X-ray diffraction (XRD) analysis and the crystalline size was calculated by the Scherrer’s formula(52nm) and as well as Williaman-Hall(W-H) equation(59 nm). The Dynamic Light Scattering (DLS) analysis shows the stability and particle size approximately 88-94 nm of the synthesized TiO2 NPs. The Fourier Transform Infrared Spectroscopy (FTIR) analysis confirms the presence of various functional groups in the synthesized NPs. The UV absorption wavelength observed at the peak of 351 nm and the calculated energy band gap is found to be 3.27eV. The surface morphology of the synthesized TiO2 NPs is determined by using Scanning Electron Microscopy (SEM). The rate of photodegradation of zoxamide in acetonitrile/water solvent system followed pseudo first-order kinetics, and calculated half-lives were found to be in the range of 2.33 -10.46 h. From this study, one photoproduct was isolated and characterized on the basis of column chromatography, mass spectral data and X-ray crystallography. The isolated photoproduct was identified as 3,5-dichloro-4 methyl benzoic acid. The plausible mechanistic pathway of formation of the photoproduct is also depicted. Langmuir–Hinshelwood (L–H) kinetic model was proposed for the rate equation of the zoxamide photodegradation in presence of TiO2 NPs under UV irradiation.
Abbas Ahmadi; Mohammad Hossein Sarrafzadeh; Maryam Mohamadi; Zeinab Mahdigholian; Akram Hosseinian
Abstract
< p>Membrane hybrid processes represent innovative separation technologies in which each technique complements the advantages and overcomes the challenges of the other. Dye removal from wastewater is an application for which membrane hybrid processes are widely applied. The focus of this study ...
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< p>Membrane hybrid processes represent innovative separation technologies in which each technique complements the advantages and overcomes the challenges of the other. Dye removal from wastewater is an application for which membrane hybrid processes are widely applied. The focus of this study is also on development of a membrane hybrid process for dye removal from wastewater. Different proportions of NH2-MIL125(Ti) were embedded in a PSf polymeric membrane through the phase inversion method and the membrane performance was evaluated for the degradation of a Methylene Blue dye under three different light conditions of dark environment, UV and visible light irradiation. The synthesized membranes were characterized by FTIR, XRD, and FE-SEM measurements. NH2-MIL125(Ti) nanoparticles were successfully entrapped in the PSf membrane through a simple phase inversion method and addition of NH2-MIL125(Ti) to the PSf membrane resulted in the improvement of membrane porosity. Up to 60% of dye degradation was observed with the 1% NH2-MIL125(Ti)/PSf nanocomposite membrane after 300 minutes of UV light irradiation. Degradation kinetics followed a pseudo first order model, evidence of possible changes in the membrane properties upon irradiation with simulated solar radiation.
Farnosh Tavakoli; Alireza Badiei; Jahan Bakhsh Ghasemi
Abstract
In this paper, Ag-TiO2-Graphene (Ag-TiO2-G) photocatalyst is synthesized via an economic and green rout. Pranus Cerasus is applied as a green reducing agent due to the presence of anthocyanin pigment. The anthocyanin molecules are responsible for the red color of the prunus cerasus seeds. The nanocmposites ...
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In this paper, Ag-TiO2-Graphene (Ag-TiO2-G) photocatalyst is synthesized via an economic and green rout. Pranus Cerasus is applied as a green reducing agent due to the presence of anthocyanin pigment. The anthocyanin molecules are responsible for the red color of the prunus cerasus seeds. The nanocmposites were characterized by XRD, EDS mapping, DRS and TEM. In order to explore the presence of Ag, different mass ratio of Ag to in Ag-TiO2-G composite (5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt% and 50wt%) were synthesized and their performance on the Acid Orange 7 (AO7) photodegradation were compared with bare graphene. In addition, for investigation of the presence of graphene, the Ag-TiO2 was synthesized and compared with the Ag-TiO2-G composite from the photocatalytic performance point of view. Ag nanoparticles and graphene are two crucial factors in AO7 photodegradation. Finally, we showed that photodegradation of AO7 with photocatalyst depends on photogenerated holes.
Saied Saeed Hosseiny Davarani; Hamid Reza Moazami; Taher Yousefi; Masoud Abrari
Abstract
A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance ...
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A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance UV-Vis spectroscopy (DRS), Fourier transforms infrared spectrometry (FT-IR), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the crystalline structure, morphology, and energy band gap of the products can be finely adjusted only by varying the duty cycle of the anodeswitching. The visible light activity of the obtained nanostructures was investigated using methyl orange as a model organic pollutant. It was found that the proposed method can be used to obtain very effective CdxZn1-xO photocatalysts by fine tuning of the morphology and energy band gap. The prepared photocatalyst retained 80% of its original activity after 5 replicated uses.