Sharif Digital Repository

Developing an efficient visible-light-driven photocatalyst is believed to be a practical solution for clean energy and environmental remediation. The present study aimed to broaden current knowledge of the graphitic carbon nitride (g-C3N4)-based plasmonic photocatalysts by decorating polydopamine-grafted g-C3N4 (PDA/g-C3N4) with silver nanoparticles (AgNPs). The nanocomposite was prepared using a facile synthesis method, while XPS and microscopy measurements confirmed the homogenous dispersion of AgNPs on PDA/g-C3N4. AgNPs successfully reduced the recombination rate of photoinduced electron-hole pairs. The calculated bandgap energy was decreased from 2.7 eV for pure g-C3N4 to 2.1 eV for... 

Global environmental pollution and energy supply demand have been regarded as important concerns in recent years. Metal oxide semiconductor photocatalysts is a promising approach to apply environmental remediation as well as fuel generation from water splitting and carbon dioxide reduction. ZnO nanostructures have been shown promising photocatalytic activities due to their non-toxic, inexpensive, and highly efficient nature. However, its wide band gap hinders photo-excitation for practical photocatalytic applications under solar light as an abundant, clean and safe energy source. To overcome this barrier, many strategies have been developed in the last decade to apply ZnO nanostructured... 

A conic body packed bed reactor, internally irradiated with a UV-C lamp and equipped with circulating upflow stream was employed to investigate the decomposition of a widely used azo dye, direct red 16, in water. The synthesized nanostructure TiO 2 photocatalyst particles were immobilized on the surface of transparent Raschig ring packings. Solutions with initial concentration of 30 mg L -1 of dye, within the range of typical concentration in textile waste waters, were treated under the mild operating conditions of natural pH of 6.75 and temperature of 25 °C. Investigations on the active species showed that hydroxyl radicals play the major role in the process, providing a perfect degradation... 

The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). Besides, specific surface area was also determined by BET method. The four effective factors including pH of the reaction mixture, Fe3O4/ZnO magnetic nanoparticles concentration, initial MTBE concentration and molar ratio of [H2O2]/ [MTBE] were optimized using response surface... 

Zeolite-based photocatalysts were prepared by the sol-gel and deposition methods. The photocatalysts were characterised by X-ray diffraction, nitrogen adsorption-desorption isotherms, FTIR spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectrometry. The activity of the prepared photocatalysts was evaluated by the UV-induced degradation of acid blue 92, a textile dye in common use. The effect of various parameters, such as catalyst concentration, initial dye concentration, thiosulphate concentration and pH, on the rate and efficiency of the photocatalytic degradation of acid blue 92 was investigated. The results showed that each parameter influenced the degradation... 

Mordenite (MOR) nanocrystals were synthesized using the hydrothermal method. Sol–gel and deposition methods were utilized to modify the zeolite surface with TiO2 and then AgBr or AgCl particles. Photocatalysts were characterized by using X-ray diffraction, Brunauer–Emmett–Teller (BET), and scanning electron microscopy techniques. Activity was evaluated by photodegradation of Acid Blue 92 as an azo dye. The effect of silver halide deposition on the photocatalytic behavior of the prepared nanocomposites was studied under both ultraviolet (UV) and visible light, and the results were compared. The results showed that AgCl/TiO2/MOR was more active under UV, while with visible source,... 

ZnO/CuO nanofibers, with different CuO concentrations, were fabricated by one-step electrospinning of the polymer precursor and annealing in air. Scanning electron microscopy (SEM) showed smooth and beadless morphology for the synthesized nanofibers, while X-ray diffraction (XRD) analysis revealed formation of hexagonal and monoclinic crystalline structure phases for ZnO and CuO nanofibers, respectively. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of CuO on the surface of ZnO nanofibers. For further confirming the formation of chemical bonds, Fourier transform infrared (FT-IR) spectroscopy was employed. The effect of Cu contents in the overall electronic band... 

While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is investigated for the... 

While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is... 

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... 

The photocatalytic degradation of p-nitrophenol (PNP) using TiO2 particles immobilized on a fiberglass cloth was investigated in a novel design of a photo-impinging stream reactor. A spray painted method has been used for the coating process. The structural properties of the immobilized sample were examined using X-ray diffraction and a scanning electron microscope (SEM). The photocatalytic degradation results showed the good performance of the reactor. The flow regime within the reactor was characterized and modeled by applying a liquid residence time distribution. A compartment model consisting of four continuous stirred regions was assigned to describe the flow pattern in the reactor. A...