جستجوی مقالات مرتبط با کلیدواژه « فوتوکاتالیست » در نشریات گروه « شیمی »

In this research, the nanocomposite of perlite@CoO@reduced graphene oxide (PC-RGO) was successfully synthesized fabricated, and characterized by XRD, FT-IR, and SEM images. Diffuse Reflectance Spectroscopy (DRS) was used to find the photocatalytic ability of this nanocomposite. In addition, photocatalytic degradation of hazardous compounds (methylene blue) by the prepared nanocomposite under LED irradiation was reported. The effects of pH, contact time, dye and adsorbent concentration and temperature are all taken into consideration. The adsorption kinetics results are adjusted to best fit the pseudo-second-order model. The experimental data are analyzed by Langmuir isotherms. The best results found in the adsorption experiments were pH 11, 10 ppm methylene blue, 0.1 gr adsorbent, and 60 minutes of contact time. The results of experiments show that as-prepared nanocomposite can be applied as a low-cost, accessible photocatalyst and adsorbent for the removal of organic pollutants from water.

A review on two-dimensional MXene materials and their application for increasing the photocatalytic properties of semiconductorsRezvaneh Amrollahi*, Pooneh NayebiDepartment of physics, Iran university of science and technology, Tehran, IranAbstract:The two-dimensional transition metal carbides, nitrides and carbonitrides (MXenes) ,that were first synthezied in 2011, have found many application in ion batteries, sensors, energy storage devices, and etc due to their high chemical diversity, structural complexities and electrical conductivity similar to metals. In addition, the MXene family is one of the most valuable candidates for improving and boosting the photocatalytic performance of semiconductors beacuse of its special surface, functional groups and also accelerating the separation of charge carriers. In this review, we tried to introduce the structure, prepration method of MXene and its effect on the photocatalytic properties of semiconductors for photodegradation of dyes, water splitting reaction, and CO2 conversion.

In this study, Ag, Ce codoped ZnO/polyaniline nanocomposites were synthesized as photocatalysts for the simultaneous degradation of organic pollutants para nitrophenol and methylene blue under UV light. XRD, FESEM, and UV-Vis analyzes were used to determine the physical, chemical, and optical properties of the synthesized samples. Photocatalytic experiments showed better performance of Ag-Ce-ZnO/PANI nanocomposite compared to other samples. The results showed that after 60 minutes, about 88% of methylene blue and 56% of para nitrophenol were degraded by this nanocomposite. The good photocatalytic performance of Ag-Ce-ZnO/PANI nanocomposites can be attributed to the reduction of electron-hole recombination, increased electrical conductivity, and increased adsorption. The stable and efficient photocatalytic activity of the prepared nanocomposite identifies it as an effective photocatalyst in the degradation of organic pollutants solely or simultaneously.

The aim of this study was to investigate the photocatalytic effect of magnetocite-copper(II) oxide core-shell nanocomposites on the rate of degradation of bisacodyl using 20 W light emitting diode lamp. For this purpose, the effect of parameters such as drug concentration, nanocomposite content, pH of the solution, the effect of stirring the solution and the effect of dissolved oxygen under photocatalytic process has been investigated. research findings showed the effective efficiency of core-shell magnetite-copper(II) oxide nanocomposite and 20 W light emitting diode lamp in photocatalytic degradation of bisacodyl drug in optimal parameters, ie bisacodyl concentration of 20 mg / L, amount of core-shell magnetite-copper(II) oxide nanocomposite 0/1 g and the pH of solution 7 and stirring speed 750 rpm in air atmosphere. In this study, the results obtained in the process of photocatalytic degradation of bisacodyl using nanocomposites of core-shell magnetite-copper oxide in the presence of 20 watt light emitting diode lamp, shows the effective efficiency of this analytical method.

Photocatalytic removal of bisphenol A, one of the most widely and emerging pollutants in the aquatic environment, was investigated by advanced oxidation process under natural sunlight. The removal process by a metal-organic framework, synthesized with phosphonic acid ligand, namely STA-12 (Fe) and hydrogen peroxide revealed excellent results. Therefore, the optimal conditions for the degradation of bisphenol A by the photo-Fenton mechanism were studied. The removal process follows the first-order kinetics with respect to the contaminant and a significant synergy was observed in the catalytic system of hydrogen peroxide/sunlight/STA-12 (Fe). The Optimal values for pH, irradiation time, catalyst amount and H2O2 dosage for oxidation of bisphenol A in 30 mg / l aqueous solution were determined to be 5, 90 minutes, 10 mg and 12 μl, respectively. Under these conditions, the best removal efficiency was 79.8%. Also, the mineralization value of organic pollutant was determined to equal 51% by measuring TOC. To determine the most important species that affected the photocatalytic reduction, trapping experiments were carried out, using various kinds of scavengers and the results showed that the hydroxyl radicals (•OH) are the main oxidizing agent in the photocatalytic system and superoxide radical and the holes in the photocatalyst surface are less involved in the process of contaminant degradation. Finally, a probable reaction mechanism has been investigated in detail. In addition, the catalyst has recyclability and stability in the photocatalytic reaction. This study is the first report for application of a phosphonate-based MOF for the removal of an emerging pollutant with a photo-Fenton mechanism and presents a new example of solar-driven advanced oxidation process for the treatment of aquatic sources and environmental protection.

In this research work, the rGO/ZnFe2O4 photocatalyst was prepared by hydrothermal method and characterized and identified using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), Diffuse Reflectance Spectroscopy (DRS), vibrating-sample magnetometer (VSM), surface area analysis (BET) and Energy-dispersive X-ray spectroscopy (EDAX) techniques. The photocatalyst was used for the reduction of nitroaromatic compounds to their corresponding aromatic amines with hydrazine monohydrate. The catalyst showed the best activity in the reduction of 1,4-dinitrobenzen (%97 conversion in 40 min). The recyclability and reusability of the catalyst was evaluated for four times which showed no significant variation in the conversion of nitrobenzene photoreduction reaction.

In this study, titanium dioxide (TiO2) containing 1 wt% of various elements (Ag, Cr, Cu, V, or Pt) was synthesized by a one-pot sol-gel method. The produced materials were extensively characterized by means of X-ray diffraction (XRD), BET surface-area measurements, Raman spectroscopy, UV-Vis spectroscopy and Transmission electron microscopy (TEM). UV-Vis spectroscopy demonstrated a clear shift in the absorbance of modified TiO2 towards the visible light region. The photocatalytic performance of the prepared materials was evaluated in the photooxidation of methylcyclohexane (MCH) under the illumiation of UV or Visible light. The performance was monitored by in situ ATR-FTIR. The best catalytic performance was obtained when Cr/TiO2 was applied. The photocatalytic activity under visible light illumination could be further enhanced by photodeposition of Pt nanoparticles (0.06 wt % Pt) on the surface of Cr/TiO2. The origin of the synergetic effect of Cr6+ and Pt nanoparticles will be discussed.

Ag/ZnO magnetic photocatalyst based on Bentonite (Ag/Fe3O4/ZnO/Bentonite) was synthesized by green method and investigated by various techniques: XRD, FT-IR, -EDAXSEM and VSM. To synthesize this nanocomposite, first Zno nanoparticles were synthesized on bentonite substrate by green method in the presence of vulgare extract and then Fe3O4 and Ag nanoparticles were prepared on ZnO/Bentonite. The prepared nanocomposite showed high photocatalytic properties for the decomposition of methylene blue (MB) and Eriochrome Black T (EBT) in the presence of sunlight, and the decomposition kinetics of MB and EBT followed the Langmuir-Hinslowwood model. On the other hand, the decomposition of colors and weight loss of the nanocomposite was very low after five tests, indicating that the synthesized magnetic nanocomposite has a high stability and is easily recoverable.

The world´s population is rising and supplies of drinking water are declining. Water pollution by pesticides is considered as one of the environmental problemsand the removal of pesticides from water sources has been of interest to researchers. One of the methods for removing toxins from water sources is the use of catalyst and photocatalyst materials. One of the most widely used materials in this field is titanium dioxide, which has been one of great interest to researchers for its photocatalytic properties. Studies have shown that this substance is used to remove phenol. However, few studies have been carried out to remove Carbendazim. In this research, it has been attempted to study and analyze the conditions for removal and degradation of Carbendazim as a pollutant by obtaining a catalyst based on titanium dioxide with a nanostructure. For this purpose, Titanium dioxide nanoparticles were synthesized by sol-gel methodand some copper was added as a pollutant. To identify and study the X-ray diffraction patterns XRD, scanning electron microscopy SEM, infrared IR spectroscopy, porosimetry BET, ultraviolet-visible spectroscopy UV-VIS and energy X-ray Diffraction EDX was used. The results showed that the synthesized nanoparticle size was about 40-50 nm and the morphology of particles is spherical. The synthesized catalyst at 400 ° C had anatase phase. The anatase phase of this material was used for degradation of Carbendazim under photocatalytic conditions and the pH parameter was also optimized. In fact, with the increase of the copper impurity at the value of 0.5 gr, the optical band gap has decreased and the absorbance has been shifted to the bulkier wavelengths. So, titania-copper composite with anatase phase and degradation of fungicidal Carbendazim with 88 yield, it can be used as a nanostructure photocatalyst for the removal of water pollutants.

In this paper, Fe3O4 modified with CuV2O6 was synthesized for the first time and its efficiency as a photocatalyst was evaluated. The new nanocomposite was characterized using UV-Vis spectrophotometry, X-ray diffraction, Fourier transform infrared spectroscopy and a field emission scanning electron microscope. Then, as a photocatalyst it was tested for methylene blue degradation in the presence of visible light. The results showed that Fe3O4 modified with CuV2O6 is more efficient than unmodified Fe3O4. Its high efficiency is due to the high absorption of visible light by the nanocomposite. Also, the conditions of the test, including the amount of photocatalyst, color concentration and pH of the solution were optimized. The synthesized photocatalyst can degrade methylene blue in the presence of visible light with high efficiency.

Methylene blue dye is the most common dye for dyeing cotton, wool and silk. Inhalation of this dye can cause respiratory distress and while direct exposure to it can also cause permanent eye damage, burning sensation in the exposed areas, Nausea and vomiting, excessive sweating and mental disorders. In this paper, silver nanoparticles was synthesized via a simple method. Various techniques such as FESEM, XRD, UV-Vis DRS were used to identify the morphology, structural composition and optical properties of synthesized silver nanoparticles. The results of UV-Vis DRS showed that the prepared silver nanoparticles effectively improved the efficiency of the visible light response in the process of photocatalytic degradation of methylene blue dye. The results of pseudo-first-order linear kinetics showed that the value of k increased with increasing of MB dye concentration from 0.0264 to 0.0614 min-1. In general, nano-silver synthesis showed a high potential in removing MB dye from aqueous solutions.