Sharif Digital Repository

This study focused on the synthesis of TiO2-Zeolite nanocomposite through a sol-gel approach. The decrease in the size of the nanocomposite is considered a primary parameter to improve photocatalytic activity. In this regard, fabricated samples were exposed to laser irradiation (532 nm) for four different time intervals in order to investigate the size variation of the nanocomposite. FTIR, UV-Vis, XRD, DLS, SEM and EDX analyses were applied to characterize and determine the size of the products. An optimized nanocomposite sample, in term of the particle size, was used for photodegradation of 2,4-D herbicide from aqueous solution. Photodegradation was carried out under UV irradiation (12 W)... 

In this work, the combination of H2O2 and an active visible-light-driven photocatalyst (Ag-S/PEG/TiO2) was utilized under natural solar radiation for the degradation of 2-nitrophenol (2-NP), and interaction effects between the photocatalyst and hydrogen peroxide were analyzed. For this purpose, experiments were designed using the response surface methodology based on the central composite design. The resulting data was utilized to obtain a model for the prediction of response (the degradation efficiency) as a function of two independent factors (H2O2 concentration and the photocatalyst loading). The statistical analysis indicated that optimum values of each of the two independent factors... 

Abstract: Photocatalysis using semiconductors has emerged as a promising wastewater treatment process to overcome the major challenges faced by conventional technologies. The advantages of ZnO nanomaterials over other semiconductors, and their structure-dependent properties, make them important building blocks in nanotechnology as multifunctional materials. Moreover, it has been confirmed that ZnO nanomaterials can exhibit high performance in photodegradation of organic dyes for treatment of industrial effluent. The wurtzite structure of ZnO contains polar and nonpolar planes; the low surface energy and thermodynamic stability of the nonpolar planes enable formation of one-dimensional (1D)... 

Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (Eg) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%).... 

In this research, adsorption and photocatalytic degradation process were utilized to remove organic dye from wastewater. To accomplish that, a newly-designed ternary nanostructure based on Ag nanoparticles/ZnO nanorods/three-dimensional graphene network (Ag NPs/ZnO NRs/3DG) was prepared using a combined hydrothermal-photodeposition method. The three-dimensional structure of graphene hydrogel as a support for growth of ZnO nanorods was characterized using field emission scanning electron microscopy (FESEM). In addition, diameter of silver nanoparticles grown on the ZnO nanorods with the average aspect ratio of 5 was determined in the range of 30–80 nm by using transmission electron microscopy... 

Recently, aluminum titanate (Al2TiO5)-based nanostructures have been proved to serve as an efficient photocatalytic material with satisfactory photodegradation capacity. In this study, the citrate sol–gel method was used to synthesize these nanostructures and inspect the significant impacts of nitrogen-doping-originated crystalline defects on their photocatalytic performance in some details for the first time. The results indicated that the penetration of nitrogen atoms into AT crystal lattice, depending on the nitriding time and temperature, can induce a great deal of the residual stress and result in propagating the existing cracks and breaking down the particles. The XPS and FTIR results... 

In this study, organic contaminant degradation was intensified by increasing the oxidative capacity of the reaction system through simultaneous photocatalysis and heterogeneous persulfate activation. Fe nanoparticles were served as a multifunctional modifier to enhance the photoactivity of graphitic carbon nitride (CN), by tuning optical properties as well as persulfate (PS) activation rate, by introducing a new activation pathway. The synthesized photocatalysts were characterized by X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), UV-visible... 

A new multifunctional filtration membrane was prepared by twofold advantages of conventional polymeric-membrane as the supporting layer and magneto-plasmonic Ag-doped ZnO@Fe3O4/MWCNTs nanocomposite as the functional layer. Poly acrylic acid (PAA)-modified polyamide (PA) discs (PAA-PA) were applied to increase the hydrophilicity of prepared membrane and X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for characterization. The grafting yield of PAA in the pores and on the surface of PA was 17 wt.% and weigh difference between PAA-PA membrane before and after modifying with the photocatalyst was 8.7 mg. The amount of photocatalyst loading in the prepared... 

In this paper, we report the preparation of a new composite (TiO2/SiO2/γ-Fe2O3/rGO) with a high photocatalytic efficiency. The properties of the composite were examined by different analyses, including X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), photoluminescence (PL), UV-Visible light diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy (FTIR), Raman, vibrating-sample magnetometer (VSM), and nitrogen gas physisorption (BET) studies. The photocatalytic efficiency of the proposed composite was evaluated by the degradation of methylene blue under UV and visible light, and the results were compared with titanium dioxide (TiO2), where... 

Introduction: In recent years, the use of cost-effective, multifunctional, environmentally friendly and simple prepared nanomaterials/nanoparticles have been emerged considerably. In this manner, different synthesizing methods were reported and optimized, but there is still lack of a comprehensive method with multifunctional properties. Materials and Methods: In this study, we aim to synthesis the copper oxide nanoparticles using Achillea millefolium leaf extracts for the first time. Catalytic activity was investigated by in situ azide alkyne cycloaddition click and also A3 coupling reaction, and optimized in terms of temperature, solvent, and time of the reaction. Furthermore, the... 

In the present study, a novel α-MnO2/AgI photocatalyst was successfully fabricated by using hydrothermal/precipitation methods, and its photocatalytic performance was evaluated from the degradation of Acid blue 92 (AB92) dye under visible light irradiation. The surface and crystalline structure, morphology, and electro-chemical properties of the as-made photocatalyst were investigated by BET, XRD, XPS, SEM-EDS, TEM, DRS, PL, PC, and Raman analysis. The optimized nanocomposite (α-MnO2/AgI) with a weight ratio of 1:15 showed the best photocatalytic activity in the decomposition of AB92 with a removal efficiency of 100% in 40 min which was better than that of pure α-MnO2 (48%) and AgI (61%),... 

The photocatalytic decolorization of aqueous solutions of Direct Red 27 in the presence of various amounts of semiconductor powder suspensions has been investigated in a batch reactor with the use of artificial light sources. ZnO and TiO2 have been found the most active photocatalysts; the effect of catalyst loading and type on the reaction rate was optimized for maximum degradation. The results imply that 1:1 ratio is proper for the photocatalytic removal of Direct Red 27. In addition, the effects of particle size and surface area were examined in this photocatalytic process. The results showed that the decolorization efficiency increases with increase in surface area, and decrease in... 

In this paper, we discuss the synthesis and characterization of tungsten trioxide nanoparticles prepared by the arc discharge method in deionized (DI) water. The size and morphology of WO3 nanoparticles prepared using different arc currents (25, 35 and 45 A) were studied. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) results indicate that at an arc current of 25 A, the size of the particles is about 30 nm, and this increases to 64 nm by increasing the arc current. This size increase caused a decrease of optical band gap from 2.9 to 2.6 eV. X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) spectra demonstrate the formation of the WO3 phase.... 

TiO2 deposited on a membrane of Ag fibers was prepared as a photoelectrochemical cell electrode. Ag fibers were made by reduction of Ag complexes on cellulose fibers, followed by burning out the template. TiO 2 photocatalyst layers were grown on the fibers by electrophoretic deposition of TiO2 nanoparticles. Ag fibers could be uniformly deposited. Photocatalytic tests by dye decomposition and electrochemical impedance spectroscopy (EIS) under UV illumination demonstrate that Ag fibers act as a good substrate that provides both high surface area and good separation of photogenerated electron-hole pairs and causes the enhancement of photocatalytic activity in comparison with a thin film of... 

In the present work we report the enhanced UV light photocatalytic performance of cadmium titanate photocatalyst by MoO 3 for Drug pollutant degradation. The nano photocatalyst sample was synthesized employing the Pechini-ultrasonic-hydrothermal route. Therefore, the nano photocatalyst were characterized by various analytical devices. The wide scan X-ray photoelectron spectral study confirmed the MoO 3 in the CdTiO 3 matrix. The crystallite size calculated with the Debye-Scherrer equation (55.4, 57.0, 61.2 and 63.1 nm for pure CdTiO 3 , MoCdTi-0, MoCdTi-1, and MoCdTi-2 nanocomposites, respectively). SEM micrographs revealed nanowire morphology indicated the crystalline nature of the sample.... 

Apatite-coated Ag/AgBr/TiO2 was prepared by deposition of Ag as novel metal to generate electron-hole pairs by extending the excitation wavelength to the visible-light region, AgBr, and hydroxy apatite as photosensitive material and adsorption bioceramic, respectively. The energy dispersive X-ray spectrometry clearly showed the presence of Ti, Ag, Ca, and P elements on the surface of catalyst. The bactericidal experiments in dark media indicated that only the novel catalyst shows inhibiting growth of bacteria in this case. A transmission electron microscopy image illustrated that catalyst nanoparticles adhere to the outer membrane of the cell and act as an inhibitor to the nourishment of... 

Titania nanofibers were prepared using a colloidal solution of Titania nanoparticles and a templating method. The preparation comprises impregnation of cellulose fibers in the solution containing Titania nanoparticles followed by thermal removal of the cellulose template. It is evidenced by scanning electron microscopy (SEM) that the residue substance consists of micron size fibers with a microstructure of nanofibers. The pore size distribution of the substance is multi-scale and fractal morphology was demonstrated with two fractal regimes with dimensions of 1.78 and 2.97 for sizes below and above 7.5nm, respectively. The surface area of the Titania fibers was measured about 250m2/g. The... 

The photocatalytic degradiation of phenol by nanoTiO2 particles coated on perlite as a new composite nano-catalyst was investigated. Titanium dioxide (Degussa P-25) was immobilized on three different supports (perlite granules, glass plates and steel fiber) by a very simple and inexpensive method. Perlite granules have a porosity of more than 95%, which allows them to stay afloat on water surface. This gives the medium a unique characteristic from the processing point of view, which enables it to get wetted with the polluted solution without requiring any pumping and simultaneously be exposed to the radiation source when coated with the photocatalyst. The photocatalytic activity of prepared... 

Herein, MIL-101(Fe), CoFe2O4, novel binary (MIL-101(Fe)/CoFe2O4, MIL-101(Fe)/GO and CoFe2O4/GO), and ternary (MIL-101(Fe)/CoFe2O4/(3%)GO and MIL-101(Fe)/CoFe2O4/(7%)GO) magnetic composites based upon the MIL-101(Fe) were synthesized. The XRD, FESEM, TEM, EDX, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses were applied to characterize samples. The MIL/CoFe2O4/(3%)GO demonstrated the best performance compared to other samples for visible light photocatalytic and photo-Fenton-like degradation of Direct Red 23 (DtR-23), Reactive Red 198 (ReR-198) dyes as well as Tetracycline Hydrochloride (TC-H) antibiotic. Degradation of dyes using the ternary composite after 70 min of... 

AgNPs@Chitosan and Co3O4-NPs@Chitosan were fabricated with Salvia hispanica. Results showed MZI values of 5 and 30 mm for Co3O4-NPs- and AgNPs@Chitosan against S. aureus, and 15 and 21 mm for Co3O4-NPs- and AgNPs@Chitosan against E. coli (24 h, 20 μg/mL), respectively. MTT assays showed up to 80% and 90%, 71% and 75%, and 91% and 94% mammalian cell viability for the green synthesized, chemically synthesized AgNPs and green synthesized AgNPs@Chitosan for HEK-293 and PC12 cells, respectively, and 70% and 71%, 59% and 62%, and 88% and 73% for the related Co3O4-NPs (24 h, 20 μg/mL). The photocatalytic activities showed dye degradation after 135 and 105 min for AgNPs@Chitosan and...