Activity For Degradation Of Organic Dyes Research Articles

Hybrid sonoprecipitation fabrication of magnetic ZnO-GO-Fe3O4 nanophotocatalyst for solar-light-driven degradation of dyes in water

ZnO-GO-Fe3O4 as an effective magnetic nanocomposite in photodegradation of water pollutants is prepared via two step procedure and its photocatalytic activity for organic dyes degradation is investigated. The first step is sonoprecipitation synthesis of ZnO over graphene oxide nanosheet and the second step is addition of Fe3O4 nanoparticles by two methods: precipitation synthesis and solvothermal addition. X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analysis (EDX), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller (BET) Surface Area Analysis and Barrett-Joyner-Halenda (BJH) Pore Size and Volume Analysis, Differential reflectance spectroscopy (DRS), Fourier Transform Infrared spectroscopy (FTIR) and Vibrating-Sample Magnetometer (VSM) techniques are employed to examine the characterization of the nanocomposites. The results display high surface area with mesoporous structure and low energy band gap is obtained for ZnO-GO-Fe3O4 synthesized via solvothermal method. Also, ultrasound irradiation increases the available surface area for photoreaction. The degradation percent of eosin yellow and methylene blue are about 60 and 97%, respectively. The effect of initial pH of solution, the amount of loaded photocatalyst and initial dye concentration are investigated in this research.

Synthesis and photocatalytic mechanism of visible-light-driven Ag/AgBr/(I/S) composites for organic dyes degradation

Series of visible light responsive Ag/AgBr/(I/S) composites based on I/S were synthesized by deposition-precipitation method. Methyl orange (MO) and other organic dyes were used to evaluate the photoactivity of Ag/AgBr/(I/S) composites. The results showed that Ag/AgBr/(I/S) composites display a good photocatalytic activity for organic dyes degradation. As the content of Ag/AgBr was 25 wt%, Ag/AgBr/(I/S) composites exhibited the best the photocatalytic activity for organic dyes. The degradation rate of Rhodamine B (RhB) and MO were 90% and 92% after 20 min. Furthermore, cycling experiments revealed that the 25%Ag/AgBr/(I/S) composites had long-term recycling stability. The photocatalytic mechanism of Ag/AgBr/(I/S) composites to MO degradation was studied by free radical trapping experiments and electron paramagnetic resonance (EPR) test, which indicating that photogenerated ·O2− is the dominant reactive specie.

A Comparative Study of Photodegradation Behavior Sodium Niobate Nanowires and Microcubes

Sodium niobate catalysts with different morphologies of nanowires and microcubes have been prepared by hydrothermal method. The photocatalytic performance of NaNbO3 nanowires and microcubes was evaluated by degradation of rhodamine B (RhB) and cationic red X-GRL (CRX). The photodegradation reaction of organic dyes is shown to be kinetically first-order. The as-prepared NaNbO3 nanowires exhibit higher photo-catalytic activity for organic dyes degradation than NaNbO3 microcubes, which is attributed to the larger specific surface area and ferroelectric phase structure.

Superior sunlight photocatalytic of N/La codoped ZnO nanostructures synthesized using different chelating agents

N/La codoped ZnO exhibited high sunlight activity, good reusability and rapid photodegradation for Congo red, malachite green and methylene blue dyes. Pure and N/La codoped ZnO were synthesized by sol gel using different chelating agents. All XRD patterns are fully indexed to hexagonal wurtzite structure of ZnO. The XRD peak shift and the increases in unit cell volume confirm the effective incorporation of N/La ions into ZnO. N/La blend extended the absorption ability of ZnO nanostructures to visible light region. Pure and N/La codoped ZnO synthesized by citric acid showed homogenous spherical nanoparticles distribution. Oxalic acid induced the formation of nanosheets and fine nanoparticles in N/La codoped ZnO. The adsorption capacity of pure and N/La codoped ZnO powders toward CR, MG and MB was less than 8%. The degradation of CR, MG and MB dyes under sunlight without catalyst is very weak. N/La codoped ZnO nanostructures exhibited superior sunlight photocatalytic activity for organic dyes degradation. N/La codoped ZnO–C and N/La codoped ZnO–O samples displayed remarkable photodegradation activities within 92–97% for CR, MG and MB in 60 min. N/La codoped ZnO–C showed a perfect photostability and reusability for four cycles. N and La enhance the charge carriers’ separation and the visible light absorption in ZnO which increase the photocatalytic activity.

A Facile Synthesis of Heterojunctional BiVO4/Bi5O7I with Enhanced Photocatalytic Activity for Organic Dyes Degradation

Photocatalysis technology has risen to effectively degrade the hardly-degraded organic pollutants in recent years and the photocatalysts play an important role in striding the obstacles of the visible light response. Herein, a high-efficiency BiVO4/Bi5O7I heterojunctional photocatalysts have been purposefully designed by controlling the reactant ratios and ultrasonic time of reaction at room temperature. Photocatalytic experimentals confirm that the prepared optimal BiVO4/Bi5O7I composites displayed enhanced photocatalytic ability to degrade rhodamine B and quinoline blue under visible light irradiation. Furthermore, the photocatalysts exhibits high photostability and reusability proved by four consecutive cycling experiments. A possible mechanism of p–n heterojunctional BiVO4/Bi5O7I composites enhanced the photocatalytic performance was discussed in detail on the basis of the reactive species trapping experiments in photocatalytic degradation process.

An efficient Ce-BiOI/luffa photocatalyst with enhanced visible light photocatalytic activity for organic dyes degradation

In this paper, Ce-BiOI was innovatively prepared by a facile hydrothermal method followed by Ce-BiOI immobilizing on luffa via co-precipitation process with assistant of ionic liquid. The Ce-BiOI/luffa photocatalyst were measured by different characterization techniques including x-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrometry, photoluminescence (PL) spectra and UV–vis diffuse reflectance spectroscopy (DRS). Photocatalytic performance of Ce-BiOI/luffa was investigated by degradation of Azocarmine G (ACG) under visible light irradiating. 99.9% of ACG was degraded by Ce-BiOI/luffa photocatalyst after 200 min of visible light irradiating. At the same time, photocatalytic degradating efficiency remained at 98.5% after six-cycles tests. Enhancements of photocatalytic activity were believed to relate with the strong visible light adsorption and efficient charge separation of photogenerated electron-hole pairs. To fathom the optimum condition, influences of Ce-BiOI/luffa loading ratio and initial ACG concentration was studied in this work. Furthermore, reactive species trapping experiments were carried out to verify that holes (h+) and superoxide radical anions (·O2−) were the main reactive species in ACG decomposition.