جستجوی مقالات مرتبط با کلیدواژه "photo-catalyst" در نشریات گروه "شیمی"

Biodiesel production from waste cooking oil (WCO) holds promise as a renewable and sustainableenergy source. However, high levels of free fatty acids (FFAs) in WCO require efficient pre-treatment before transesterification. Utilizing solar energy for heterogeneous catalytic reactionsoffers an alternative to thermal-driven processes. TiO2EFBA, synthesized via the wet impregnationmethod, exhibits distinctive physicochemical properties confirming the successful incorporationof titanium dioxide (TiO2) onto the metal oxides of empty fruit bunches ash (EFBA), thereby en-hancing the catalyst’s performance and stability. Results showed that TiO2EFBA exhibits superiorFFA conversion compared to TiO2alone. Under optimized reaction conditions, employing 4 wt%TiO2EFBA catalyst, 20:1 methanol to oil molar ratio, and 2 h reaction time at room temperatureunder Ultra Violet (UV) light, achieves a remarkable 78% conversion rate of FFAs in WCO.Mechanistic investigation reveals the crucial role of electron/hole (e−/h+) species in reducingFFAs by suppressing the e−/h+mechanism. Notably, TiO2EFBA facilitates easy separation andcan be reused for 10 cycles, demonstrating its stability as a heterogeneous photocatalyst.

One of the most difficult problems of elimination colors from industrial effluent utilizing visible-light. Due to its small bandgap, vanadium pentoxide (V2O5) is receiving a lot of attention as a potential visible light for the breakdown of organic contaminants. However, the V2O5 catalyst’s quick electron-hole pair recombination restricts its use in photo-degradation. The performance of V2O5 as a photo catalyst can be enhanced by interacting with other semiconductors. In this study, we used a hydrothermal approach to prepare V2O5/ZnO nanocomposites. Using characterization methods like (FE-SEM), (EDX), X-ray diffraction (XRD), the physical characteristics of the as-synthesised products were investigated. The creation of pure ZnO, V2O5 nanoparticles and the presence of diffraction peaks associated with the hexagonal phase of ZnO, orthorhombic V2O5 were both confirmed by the XRD data. The Scherer equation was used to analyze the variance in structural characteristics. The nanocomposite’s computed energy bandgap (2.63 eV) from UV-vis spectroscopy suggested that it might be used as a photo catalyst under a UV-visible light. The ZnO/V2O5 nanocomposite production was also confirmed by FTIR spectra. FE-SEM images revealed spherical and approximately hexagonal shape. The nanocomposite contains Zn, V, and O, according to EDX examination. Photocatalytic degradation of the ZnO/V2O5 nanocomposite to removal GRL dye (59.52%).

The aim of this work is to prepare magnetic, photocatalyst and antibacterial CoFe2O4-Au nanocomposites. Aromatic dyes such as methyl orange and acid black were selected as control dyes and the results showed that were destroyed by ultraviolet light and in the presence of nanocomposites. Also, to control the non-growth and penetration of bacteria, the disk diffusion test was used against coliform, staphylococcus aureus and pseudomonas bacteria (which can be very dangerous). Related to biological risks for organisms, magnetic nanostructures are less dangerous due to their controllability. Therefore, the possible risks of entering the cell membrane and being uncontrollable are ruled out. In the first step, the magnetic core of cobalt ferrite with magnetization of 44 emu/g and magnetic coercivity of 20 Orsted was prepared. In the next step, gold nanoparticles were coated on the magnetic cores using the sono-chemical method. Scanning electron microscope, along with other common spectroscopic methods, examines the dimensions of nanocomposites.

In this study CoFe2O4 nanostructures were synthesized via a facile precipitation method without using any surfactant and capping agent in solvent of water. Then Zinc sulphides with various doping metals (Ni, Co , Cu and Ag) were prepared. Finally metal doped CoFe2O4-ZnS nanocomposites were made by a fast chemical procedure. The prepared products were subjected to various analyses of structural (XRD), optical (UV–visible) , the formation of bonds using the (FTIR) spectrometry and surface layer morphology via SEM. Vibrating sample magnetometer shows the ferromagnetic property of the ferrite nanostructures. The photocatalytic behaviour of CoFe2O4-ZnS-metal doped nanocomposites was evaluated using the degradation of three azo dyes (acid violet, acid blue, methyl orange) under ultraviolet light irradiation. The results introduce a nanocomposite with applicable magnetic and photocatalytic performance.Vibrating sample magnetometer shows the ferromagnetic property of the ferrite nanostructures. The photocatalytic behaviour of CoFe2O4-ZnS-metal doped nanocomposites was evaluated using the degradation of three azo dyes (acid violet, acid blue, methyl orange) under ultraviolet light irradiation. The results introduce a nanocomposite with applicable magnetic and photocatalytic performance.

Ethyl benzene is a volatile organic compound that is widely used in various industries. Ethyl benzene is a hazardous air pollutant not only for the environment but also for human health and hence there is a possibility of carcinogenesis in long-term exposure. Considering the fact that ethyl benzene is photo catalytic activity based in removal of VOCS vapors under visible light irradiation leading to serious health problems, the present study aimed to evaluate the gas-phase from airflow using photo catalytic property of titanium dioxide on 13X zeolite, in Ahvaz, Iran. In this experimental study, the characteristics of the catalysts were determined using BET method, X-ray diffraction (XRD), and scanning electron microscopy scanning (FESEM). Ethyl benzene vapors were produced using a dynamical condenser system and the efficiency of removal of ethyl benzene vapor depletion was investigated using 13X/UV and13X/UV/TiO2 (5 wt. %). The obtained results of the images and spectra from XRD, and FESEM showed good signs of immobilization. The findings revealed that the removal efficiency decreased by increasing the concentration from 25 ppm to 125 ppm and increasing the flow rate from 0.5 to 1.00. The removal efficiency at concentrations of 25, 75, and 125 was 57.8%, 37/2 %, and 24/64, respectively. The results showed that the use of substrates increased the efficiency of photo catalytic removal, by about 60%. It is therefore suggested that these adsorption and photo catalytic combination systems be used to remove other volatile organic compounds in the gas phase.

At the first step calcium ferrite nanostructures were synthesized via a facile precipitation method in the presence of green and compatible capping agent such as starch, poly vinyl pyrrolidone and glucose in solvent of water. Then cerium oxide nanoparticles and CaFe2O4-CeO2 nanocomposites was made by a fast chemical procedure. The effect of temperature in nanoparticles and nanocomposites concentration and precipitating agent on the morphology and particle size of the products was investigated. The prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. Also the crystalline size of nanoparticles was calculated by Debye-Scherrer formula. Vibrating sample magnetometer (VSM) shows the ferromagnetic property of the ferrite nanostructures. The photocatalytic behaviour of CaFe2O4-CeO2 nanocomposites was evaluated using the degradation of three azo dyes (acid black, acid violet and acid blue) under ultraviolet light irradiation. The results introduce a nanocomposite with applicable magnetic and photocatalytic performance.

We prepared samples including nanoparticles of ZnS via co-precipitation method in room temperature and with microwave heating using water as a “green” solvent. The procedure was repeated with various natural surfactants. XRD and SEM analysis was performed to determine the nanostructural and morphologic characteristics of nanoparticles. The mean diameter less than 100 nm for ZnS particles showed that there was well-formed pure nanostructure. SEM analysis disclosed that temperature and type of surfactant will affect the nanostructures and so we can control the nanostructure and particle size with changing such parameters. With combining of pure Carbon and ZnS nanoparticles in various proportions, Carbon - ZnS nanocomposites was prepared using microwave heating. SEM and FT-IR analysis was performed on these nanocomposites to compare them with pure Carbon and ZnS nanoparticles. We also assessed the photocatalytic potential of prepared nanocomposites using acidic and neutral pH methyl orange and Congo red solutions under UV- IR radiation. This study confirms that these nanocomposites can be used as photo-catalysts for water refinery in home and industries.

Mn3O4 nanoparticles has been synthesised from Manganese (II) acetate and Simarouba Glauca leaf extract using microwave heating. This novel method of synthesis of Mn3O4 is fast, low-cost, non-toxic and environment friendly. The synthesised product was characterised by powder X-ray diffraction(XRD),Fourier transform infrared spectroscopy( FT-IR), Ultraviolet-Visible spectroscopy( UV-Visible), X-ray photoelectron spectroscopy( XPS), Scanning electron microscopy(SEM) and Transmission electron microscopy(TEM). The prepared material was identified as of tetragonal hausmannite crystalline structure with spherical morphology and particle size 15 nm. Photo catalytic degradation ability of the synthesised product was examined by using it for the degradation of Malachite green dye in various experimental conditions under visible light. The synthesised Mn3O4 was found to be an efficient photo catalyst for the removal of Malachite green at the optimum conditions of pH 9, adsorbent dose 0.1 g and dye concentration 20ppm. This study thus reveals the applicability of nanoparticles of Mn3O4 for the removal of pollutants from industrial waste water.

CdS nanoparticles are II-VI group semiconductor in nature with suitable band gap for photoluminescence and photo-catalyst applications. CdS nanostructures were synthesized via a facile precipitation method in the presence of green capping agents such as starch, glucose, gelatin, salicylic acid in the green solvent of water. The influence of concentration, surfactant, precipitating agent on the particle size and shape of the products were examined. Then for preparation of polymer based nanocomposites, cadmium sulphide nanoparticles were added to poly styrene, poly vinyl alcohol, cellulose acetate and acrylonitrile-butadiene-styrene polymers. The prepared samples were characterized by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. The photocatalytic behaviour of cadmium sulfide was evaluated using the degradation of three azo dyes (methyl orang, acid violet 49 and acid black 1) under ultraviolet and visible light irradiation. Our results confirm preparation of pure semiconductor nanoparticles and polymer-based thin film nanocomposite with both appropriate photo-luminescence and photocatalytic performance simultaneously. Interestingly outcomes show photocatalysts can photo-degrade toxic dyes in less than 15 min.

Firstly nickel ferrite nanoparticles were synthesized via a simple precipitation method. Then mono-disperse platinum nanoparticles and NiFe2O4@TiO2/Pt nanocomposites were synthesized by a facile sol-gel procedure. The structure, phase and crystallite size of the magnetic and photo-catalyst products were characterized by X-ray diffraction pattern (XRD). The morphology and size of the nanostructures were surveyed by scanning electron microscopy (SEM). The purity of the samples was confirmed by Fourier transform infrared (FT-IR) spectroscopy. Vibrating sample magnetometer (VSM) illustrated that nickel ferrite nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of NiFe2O4@TiO2/Pt nanocomposites was approved using the fast degradation of two various azo dyes under visible and ultra violet light irradiation. The results show that nanocomposites have feasible magnetic feature for easy separation and effective photo catalytic properties for purification of organic dye contaminants. The antibacterial behaviour of NiFe2O4@TiO2/Pt nanocomposites was evaluated using degradation of E coli bacteria.

Today, despite the increasing demands for the products of chemical industries and the relatedfactories, the challenges of environmental pollution have not been improved and it is approaching avery dangerous stage. In this regard, the role of dyeing industries in contaminating the environment isundeniable. In this research, ZnO and ZnO-TiO2 nanoparticles were synthesized by co-precipitation andsol-gel methods, respectively. The synthesized nanoparticles were characterized by XRD and FE-SEMtechniques and their band gap energy were determined using the UV-Vis spectrum obtained from thesuspension of nanoparticles. By using synthesized nanoparticles, degradation of malachite green underirradiation of the UV (A) -Visible mixture light from aqueous solution were evaluated and the effect ofdifferent parameters such as amount of photo catalyst, time of light irradiation and dose of H2O2hasbeen studied. The destruction amount was determined by UV-Vis spectroscopy method. Based on thereported results, the maximum degradation efficiency of about 99% was obtained in the optimal valuesof experimental conditions.

Biosynthesis of metal nanoparticles using plant extract has received much attention due to its eco-friendly nature. The present study elucidates the green synthesize of Silver nanoparticles (AgNPs) from methanolic extract of Coleus Vettiveroids –an endemic species. The synthesis of AgNPs was confirmed by UV-visible spectrometry at 416 nm. Further, biosynthesized nanoparticles were characterized by FTIR for the confirmation of biomolecules acting as reducing agent. Average size and presence of elemental silver were characterized by scanning electron microscopy (SEM) and Transmission electron microscopy (TEM).Average size of nanoparticles was found to be 5 nm. The antioxidant ability of AgNPs was analyzed using DPPH. In vitro antibacterial effect of various concentrations of AgNPs was investigated against both Gram positive (S.Aureus) and Gram negative (E.Coli) bacterial strains. The result shows that biosynthesized AgNPs have significant antibacterial activity. Synthesized silver nanoparticles were also used effectively as photo catalyst in degradation of Organic Dyes and can be concluded that synthesized silver nanoparticles are also promising photo catalyst.

In this research we first synthesized MgFe2O4 nanostructures via hydrothermal method using (Mg(NO₃)₂.6H₂O) and (Fe(NO₃)₃.9H₂O). The influence of concentration, surfactant, precipitating agent and temperature on the particle size and magnetic properties of the synthesised nanoparticles were examined. Then MgFe2O4-Ag nanocomposites were prepared by a simple chemical precipitation. The structural characteristics of samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR). Spectroscopy vibrating sample magnetometer showed that the prepared ferrite nanostructures had ferromagnetic property. The photocatalytic aspects of MgFe2O4-Ag nanoparticles and nanocomposites were measured using the degradation of three azo dyes (acid red, acid violet and methyl orange) under ultraviolet irradiation. Our results confirm the successful formation of MgFe2O4 nanoparticles and MgFe2O4-Ag nanocomposite. It was also shown that the prepared nanostructures had appropriate magnetic properties and photocatalytic performance.
In this research we first synthesized MgFe2O4 nanostructures via hydrothermal method using (Mg(NO₃)₂.6H₂O) and (Fe(NO₃)₃.9H₂O). The influence of concentration, surfactant, precipitating agent and temperature on the particle size and magnetic properties of the synthesised nanoparticles were examined. Then MgFe2O4-Ag nanocomposites were prepared by a simple chemical precipitation.

Fe3O4 nanoparticles were synthesized in the presence of pepper extract as a capping agent via a hydrothermal method. Then palladium nanoparticles and Fe3O4-Pd nanocomposites were synthesized with the aid of pepper extract as a reducing agent. Vibrating Sample magnetometer illustrated that Fe3O4 nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of Fe3O4-Pd nanocomposites was investigated using the degradation of two azo dyes under ultraviolet light irradiation. The results show that nanocomposites have feasible magnetic and photo catalytic properties. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy.

At the first stage Fe3O4 and Fe nanoparticles were synthesized via a simple hydrothermal method. Then silver nanoparticles and Fe-Ag nanocomposites were synthesized in the presence of NaBH4. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy, and Fourier transform infrared spectroscopy. Vibrating Sample magnetometer illustrated that Fe nanoparticles have super paramagnetic behaviour. The photo catalytic behaviour of Fe-Ag nanocomposites was investigated using the degradation of three various azo dyes under ultraviolet light irradiation. The results show that nanocomposites have feasible magnetic and photo catalytic properties.

Water splitting for hydrogen production under sunlight using TiO2 as photo catalyst provides a better route for solar energy and attracts the attention of many researchers. The photo catalytic activity of TiO2 under sunlight irradiation depends on the band gap energy. The transition metal doped TiO2 shows an edge over TiO2 in optical absorbance and photo catalytic activity. Thin film of Cr doped TiO2was deposited by Electron beam evaporation deposition process on glass substrate, the band gap of sample was measured with UV-Vis spectroscopy. In order to provide theoretical ground to our experimental band gap results the first principle (ab-initio) calculation was performed using the computer code WIEN2K with Full Potential Linearized Augmented Plane Wave method (FP-LAPW) based on the density functional theory (DFT).

ZnO and Mn-ZnO nano powders were prepared by the sol-gel auto combustion method. The products were characterized by X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDX) and scanning electron microscopy (SEM). Structural and morphological properties of nano particles were investigated and the average crystalline size of ZnO and Mn-doped ZnO was obtained 44 and 51 nm, respectively. Also, photo catalytic removal of Cibacen Turquoise Blue G dye from aqueous solution by using nano scale ZnO and Mn-ZnO powders under UV light irradiation was studied. The effect of initial dye concentrations and dosage of photo catalysts, were investigated in the photo destructive process. This is 57% of dye degraded by 0.02 mg of ZnO in 70 minutes. The degradation rate increase to 84% in the presence of 0.02 mg of Mn-ZnO in the same time.

Tungsten trioxide nanoparticles with monoclinic structure and average particle size about 80 nm were prepared by the spray pyrolysis method. WO3 nanorods with hexagonal structure and average dimension about 15 × 100 nm were synthesized in gram quantities by modified hydrothermal method at lower temperature and shorter reaction time in comparison to the previous research. Photo degradation of Congo Red showed that the as-prepared WO3 nanoparticles is more effective than nanorod structure. WO3 nanorods actually had no effect in Congo Red photo degradation. Therefore in this reaction, spherical morphology is superior to column morphology. The samples were characterized with X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), EDX analysis, UV-visible spectrum and Transmission Electron Microscopy (TEM).