Sharif Digital Repository

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... 

Visible light-active BiOCl/BiVO4/mordenite and Ag/BiOCl/BiVO4 nanocomposite with a p–n heterojunction structure were prepared. Mordenite nanocrystals were synthesised using the hydrothermal method. Deposition and reduction methods were utilised to modify the Zeolite surface. The photocatalytic activities of the heterojunctions were investigated by scanning the change of Acid blue 92 (AB92) concentration under visible irradiation. The nanocomposites demonstrated improved efficiency for dye photodegradation. The activities are due to strong oxidative ability and efficient charge separation and transfer through the BiOCl/BiVO4 p–n junction. The photogenerated electron-holes react with species... 

CuO flower-like microcrystals, prepared by a facile template-free thermal method, showed incredible photocatalytic activity towards degradation of Acid Blue 92 (AB92), an organic wastewater, Escherichia coli and Staphylococcus aureus pathogenic bacteria under visible light. The products were well characterised by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), Fourier transform infrared (FTIR), photoluminescence spectroscopy (PL) and diffuse reflectance spectra (DRS) analysis methods. The XRD pattern of the products well confirmed the formation of copper oxide crystalline phase without any other impurities. The results of the photocatalytic... 

Visible light-active BiOCl/BiVO4/mordenite and Ag/BiOCl/BiVO4 nanocomposite with a p–n heterojunction structure were prepared. Mordenite nanocrystals were synthesised using the hydrothermal method. Deposition and reduction methods were utilised to modify the Zeolite surface. The photocatalytic activities of the heterojunctions were investigated by scanning the change of Acid blue 92 (AB92) concentration under visible irradiation. The nanocomposites demonstrated improved efficiency for dye photodegradation. The activities are due to strong oxidative ability and efficient charge separation and transfer through the BiOCl/BiVO4 p–n junction. The photogenerated electron-holes react with species... 

Photocatalytic decolorization of methylene blue (MB) in aqueous solution was investigated using ZnO nanoparticles immobilized on glass plate. The ZnO nanoparticles were prepared by solution combustion method (SCM) using zinc nitrate as oxidant and glycine as fuel. In the slurry ZnO system the separation and recycling of the photocatalyst is practically difficult. Thus, the ZnO nanoparticles were immobilized on glass supports to solve this problem. The effects of process parameters like, catalyst loading, initial dye concentration, and UV-radiation intensity have been investigated. The best results of MB removal were reported in the 1800 μW cm-2 UVC using two layers immobilized ZnO... 

The objective of this study was to model the extent of improvement in the degradability of phenol dyes by SnO2/Fe3O4 nanoparticles using a photocatalytic reactor. The effect of operative parameters including catalyst concentration, initial dye concentration, stirring intensity, and UV radiation intensity on the photocatalytic batch reactor during removal of phenol red was investigated. Fractional factorial design and response surface methodology were used to design the experiment layout. The SnO2/Fe3O4 nanoparticles were synthesized using the core-shell method. The results of x-ray diffraction and transmission electron microscopy showed the successful synthesis of these nanoparticles. The... 

Introduction: Porous 3D scaffolds synthesized using biocompatible and biodegradable materials could provide suitable microenvironment and mechanical support for optimal cell growth and function. The effect of the scaffold porosity on the mechanical properties, as well as the TiO2 nanoparticles addition on the bioactivity, antimicrobial, photocatalytic, and cytotoxicity properties of scaffolds were investigated. Methods: In the present study, porous scaffolds consisting poly (lactide-co-glycolide) (PLGA) containing TiO2 nanoparticles were fabricated via air-liquid foaming technique, which is a novel method and has more advantages due to not using additives for nucleation compared to former... 

Conventional wastewater treatment processes are not completely effective in removing vancomycin. In this study, affecting parameters on vancomycin degradation, such as pH, catalyst, initial vancomycin concentration, temperature, and reaction time were investigated simultaneously during a removal process based on titanium dioxide with ultraviolet irradiation in an aqueous solution. Titanium dioxide was synthesized and characterized using X-ray diffraction and scanning electron microscopy. The average size of the synthesized crystals was 4.7 (± 0.2) nm. Design of experiments was done by a central composite design based on the response surface methodology and multiple linear regression was... 

In this contribution, the effect of physical immobilization of methylene blue (MB) into silica nanocomposites was investigated on the conversion and selectivity of the photooxygenation of anthracene and dihydroartemisinic acid (DHAA). Physically immobilized photocatalysts were synthesized through a developed Stöber method and were thoroughly characterized by UV–Vis, FTIR, XRD, XPS, SEM, TEM, HR-TEM, BET-BJH, and EDX analyses. Based on the TEM and UV–Vis results, it was determined that enhancement of the MB concentration as an organocatalyst for the Stöber reaction led to an increase in the size of the nanoparticles from 54 to 183 nm and a 21 nm blue shift in their UV–Vis spectra. Moreover,... 

Photocatalytic wastewater treatment and concurrent energy production or metal ions conversion to less harmful products have great potential to address both environmental and energy challenging issues, two of the most significant problems facing humankind. Many efforts have been devoted for achieving enhanced photocatalytic activity as well as optimizing reaction conditions and materials design. In this context, various strategies were applied to develop efficient dual-functional photocatalysts for environmental purification and simultaneous energy production. Concurrent photocatalytic degradation of organic pollutants and Cr(VI) reduction to less toxic Cr(III) improved the rate of both... 

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)... 

ZnO was grown on mordenite zeolite, activated carbon and alumina substrates by a liquid deposition method. The photocatalytic activity of the synthesised samples was elucidated using the photodegradation of Acid Blue 92 (AB92) dyes as a test pollutant under UV light irradiation. Supports play a key role in AB92 photodegradation and significantly improve the photocatalytic activity of ZnO. Different supports form additional transport channels and provide an effective pathway for the charge carriers. The supports effectively construct porous structures with more active sites. Hence, the higher photocatalytic activity of supported catalysts is attributed to the large surface area and charge... 

The main aim of the present study was to enhance the degradation capacity of Acid Blue 92 (AB92) by visible-light-active Ag3PO4 nanocomposites based on g-C3N4 and Multiwalled Carbon Nanotubes (MWCNTs). The nanocomposites were fabricated through a tunable in situ deposition method. The properties of the resulting samples were investigated by X-ray diffraction, scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The photocatalytic activity results revealed that the Ag3PO4/g-C3N4 heterojunction inorganic/organic composite exhibited an improvement in both efficiency and the rate of AB92 photodegradation in comparison with the others. The enhanced photocatalytic... 

Hollow microblocks of [Zn(anic)2], as a novel coordination compound, were synthesized using 2-aminonicotinic acid (Hanic) and zinc (II) nitrate tetrahydrate. The chemical composition of the zinc complex, ZnC12H10N4O4, was determined by Fourier transform infrared (FTIR) spectroscopy and elemental analysis. The synthesized zinc complex was used as a precursor to produce ZnO nanostructures by calcination at 550 °C for 4 h. Morphological studies by scanning electron microscopy and transmission electron microscopy revealed the formation of porous microbricks of ZnO nanoparticles. N2 adsorption-desorption analysis showed that the... 

A novel visible-light-driven Ag3VO4/Ag3PO4/Ag photocatalyst was successfully synthesized via an anion-exchange reaction and characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse-reflectance spectroscopy and Fourier transform infrared spectroscopy. The photocatalytic activities of prepared catalysts were evaluated by degradation of acid blue 92 (AB92) aqueous solutions under visible light irradiation. The photocatalytic results indicated that the synthesized Ag3VO4/Ag3PO4/Ag hybrid displays a significantly enhanced activity in degradation of acid blue 92 under visible light compared with pure Ag3VO4. The improved... 

Herein, a novel quaternary Ag3PO4/BiPO4@MIL-88B(Fe)@g-C3N4 (AB@MIL-88B(Fe)@g-CN) nanocomposite with a core@shell structure is successfully fabricated in two simple steps. The prepared samples are characterized via various techniques. The photocatalytic activity of the prepared samples is evaluated by the degradation of navy Acid Blue 92 (AB92) dye as an organic pollutant under visible light irradiation. Highly enhanced photocatalytic efficiency is observed for the quaternary AB@MIL-88B(Fe)@g-CN nanocomposite compared to that for the other samples. The experimental results indicate that the photocatalytic activity enhancement is mainly attributed to the strong visible light absorption and... 

In this study, MoS2/reduced graphene oxide (rGO) was used as a cocatalyst to synthesize very highly efficient Cu2O/MoS2/rGO for cooperative catalytic applications. The resulting nanocomposite was characterized by various analytical techniques and applied for catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol and photocatalytic degradation of Acid blue 92. Cu2O/MoS2/rGO composite presents superior performance to pure Cu2O particles in both catalytic and photocatalytic reactions. This excellent activity demonstrates synergistic effect of MoS2/rGO as a cocatalyst in the nanocomposite. The role of the active sites in the reduction of 4-NP and degradation of dye was discussed and... 

The main aim of this research is to improve the photocatalytic activity of TiO2 nanotubes by co-doping with copper and sodium for application in the water splitting process as a photoanode. The doping was performed simultaneously to the anodizing process through a single-step treatment. The synthesized TiO2 nanotube array (TNA) was characterized by applying FESEM (Field Emission Scanning Electron Microscopy), XRD (X-ray Diffraction), DRS (Diffraction Reflection Spectroscopy) and XPS (X-ray Photoelectron Spectroscopy) analyses. The results of XPS analysis proved the presence of copper with valence (2+) and carbon and sodium with valence (1+). Moreover, DRS tests showed a reduction in the band... 

A new plasmonic Ag hybridized CuWO4/WO3 heterostructure was successfully synthesized via a ligand-assisted sol gel method. The as-prepared plasmonic nanohybrid was thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, photoluminescence (PL) spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis and electrochemical impedance spectroscopy (EIS). Moreover, the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation. The results indicate that the as-prepared plasmonic Ag-CuWO4/WO3 nanohybrid (compared to pure...