Catalytic Degradation Of Methyl Orange Research Articles

Microwave-assisted catalytic degradation of methyl orange in aqueous solution by ferrihydrite/maghemite nanoparticles

Six-line ferrihydrite was successfully prepared by precipitation method and characterized with XRD, SEM, TEM, BET and FTIR spectroscopy. The as-prepared ferrihydrite was used as catalyst for the degradation of methyl orange (MO) in an artificial dye wastewater without adding any oxidant. It was found that the ferrihydrite nanoparticles with average size of about 90–220nm exhibited a high adsorption capability to MO and the dye molecules obey Langmuir type of adsorption. Batch degradation experiments show that the catalytic degradation of MO could be remarkably improved by coupling with microwave irradiation. The initial pH value of MO solution exerted notable influence on the degradation reaction and the optimal degradation efficiency was obtained under neutral conditions. Radical scavenger measurements indicated that OH radicals could generate during the catalytic process even without adding oxidant. We proposed that the microwave irradiation facilitates the generation of active oxygen species derived from water and/or oxygen dissolved in water, which are responsible to the excellent performance of the MW-assisted catalytic process.

Combustion synthesized hierarchically porous Mn3O4 for catalytic degradation of methyl orange

AbstractHierarchically porous Mn3O4 has been synthesized via a facile solution combustion synthesis using Mn(NO3)2 · 4H2O as an oxidizer and ethylene glycolc (EG) as a fuel. The thermal analysis indicated that the combustion reaction can be initiated at a low temperature (126–140 °C). The obtained Mn3O4 appeared as a hierarchical network with well‐connected poroes. At room temperature, the porous Mn3O4 was found to be highly effective for catalytic degradation of methyl orange (MO) in the presence of acid.

The Catalytic Degradation Performance of α-FeOOH Doped with Silicon on Methyl Orange

In order to improve the catalytic degradation property of α-FeOOH, α-FeOOH was doped with sodium silicate. The α-FeOOH doped with silicon was used as catalyst to catalyze the degradation of methyl orange. The XRD spectra showed that the crystalline phase of α-FeOOH doped with silicon was same as that of α-FeOOH; The catalytic degradation property of α-FeOOH doped with silicon was 21.7% higher than that of α-FeOOH; The results showed that catalytic degradation of methyl orange was almost degraded thoroughly at the conditions that the concentration of α-FeOOH doped with silicon in the solution was 0.73 g/L, the concentration of H2O2 was 0.231 mmol/L. The pH value was between 2 and 3, and the degradation reaction was carried out at 60 oC for at least 20 min.

Efficient photo catalytic degradation of methyl orange over Ag–CuO nanostructures grown on copper foil under visible light irradiation

A novel and efficient photo catalyst was synthesized for the photo degradation of methyl orange. CuO nanostructures were grown on copper foil as substrate via a simple cost-effective wet-chemical route and used as templates for making silver-deposited CuO samples. Silver were deposited over the surfaces of CuO nanostructures through a photochemical deposition process. The resulting samples were characterized by X-ray diffraction, field emission scanning electron microscope and energy dispersive X-ray spectrometer methods. SEM images show formation of film containing sheet-like structures with thickness of about 20–50 nm and nanorod-like structures with the diameter and length of 40–70 and 100–500 nm, respectively. The photo-catalytic activity of samples was evaluated by monitoring the photo-degradation of methyl orange. Results demonstrated that the rate of degradation of the silver-deposited CuO sample was more than 4.4 times faster than pure CuO nanostructures. The Ag–CuO catalysts prepared in this study exhibit industrially relevant interests due to the low cost, high photo catalytic activity and high stability.

Metal oxides as dual-functional adsorbents/catalysts for Cu2+/Cr(VI) adsorption and methyl orange oxidation catalysis

The LDO, calcined product of the Mg/Al-CO3 hydrotalcite, was used as a dual-functional adsorbent/catalyst material for the removal of binary heavy metal ions and the catalytic degradation of methyl orange (MO). The adsorption properties for Cu2+ cations and Cr(VI) anions were investigated in depth in single and co-adsorption systems. The results showed that the LDO demonstrated 0.80 and 2.90 mmol/g adsorption capacities in single Cu2+ (1.6 mmol/L) and Cr(VI) (4.0 mmol/L) systems, respectively. In co-adsorption system, Cu2(OH)3Cl precipitation, isomorphic substitution of Mg2+ sites by Cu2+ and intercalation of CrO42– into the interlayers played important roles. On the LDO, Cu2+ and Cr(VI) presented synergetic effect, resulting in an increase in both Cu2+ and Cr(VI) adsorption capacities. In addition, the spent adsorbents were employed as a catalyst for methyl orange (MO) degradation. The Cr-Cu-RLDO, a calcined product of the spent adsorbent in the co-adsorption system, indicated the high activity with 86.5% degradation rate of MO in the presence of H2O2. The existence of Cu and Cr elements in the catalyst was one of the causes of the enhanced degradation of MO.

Oxidative degradation of Methyl Orange catalyzed by lab prepared nickel hydroxide in aqueous medium

This study is focused on oxidative degradation of Methyl Orange, a common azo dye, catalyzed by nickel hydroxide in aqueous solution at 303, 313, 323, and 333 K. Sodium hypochlorite, sodium hydroxide, and nickel sulfate hexahydrate in distilled water were used as starting material for preparation of nickel hydroxide. Pyrex glass batch reactor was used to study the effect of various conditions such as temperature, concentration, agitation, and catalyst dose on catalytic degradation of Methyl Orange in aqueous medium. About 80% Methyl Orange was degraded in 120 min. Experimental data were subjected to kinetic analysis using CurveExpert software. Degradation reaction was taking place according to Langmuir–Hinshelwood mechanism. According to this mechanism, the reactants adsorb at the surface of catalyst in first step followed by reaction between adsorbed reactants in second step. Adsorption of Methyl Orange on surface of catalyst followed Langmuir adsorption isotherm. Apparent activation energy, true activation energy, and heat of adsorption were determined as 13.2, 32.7 and –23.5 kJ mol−1, respectively.

Ultrasound-Assisted Catalytic Degradation of Methyl Orange with Fe3O4/Polyaniline in Near Neutral Solution

An ultrasound-assisted advanced oxidation process (AOP) has been demonstrated for sonocatalytic degradation of methyl orange (MO) with Fe3O4/polyaniline (Fe3O4/PANI) microspheres in near neutral solution (pH ∼6). The Fe3O4/PANI microspheres were characterized with XRD, SEM, TEM, FT-IR, XPS, and ζ-potential measurements, and were further tested in the role of adsorption and sonocatalytic decolorization of MO in solution. The isotherms and kinetics of MO adsorption with Fe3O4/PANI follow the Langmuir model and the pseudo-second-order model, respectively. The kinetics of sonocatalytic decolorization of MO with Fe3O4/PANI conforms to a combinational model involving the pseudo-second-order adsorption model and the pseudo-first-order degradation model, since Fe3O4/PANI has a high capacity to adsorb MO in solution. The percentage of room-temperature sonocatalytic degradation of MO with Fe3O4/PANI is about 4.8, 8.8, and 5.7 times that with Fe3O4, dedoped Fe3O4/PANI, and ultrasonication alone, respectively. The ec...

Magnetically separable copper substituted cobalt–zinc nano-ferrite photocatalyst with enhanced photocatalytic activity

A series of nano crystalline copper substituted cobalt zinc ferrites, Co0.6Zn0.4CuxFe2−xO4 (x=0.2, 0.4, 0.6, 0.8 and 1.0) with cubic spinel crystal structure were synthesized by sol–gel auto combustion method. The X-ray diffraction analysis confirmed the formation of cubic phase with Fd-3m space group of all the prepared nano-ferrites. The lattice parameter was found to increase with increase in copper substitution. This may be attributed to larger ionic radius of copper as compared to that of iron. The electrical studies revealed that all prepared ferrites are semiconducting in nature. The saturation magnetization was found to be maximum at x=0.4, obeying Neel׳s two sub-lattice model and decreased thereafter due to spin canting effect. The photo catalytic degradation of methyl orange (MO) dye by Co0.6Zn0.4CuxFe2−xO4 (x=0.2, 0.4, 0.6, 0.8 and 1.0) ferrite was studied under visible irradiation. Significant enhancement in photo degradation of MO can be ascribed to the B-site occupancy of copper ion. This catalyst is also well separable from water media by applying external magnetic field, thus it can act as a promising catalyst for the remediation of textile wastewater.

Synthesis of Co3O4 Nanomaterials with Different Morphologies and Their Photocatalytic Performances

Several facile and easily controlled approaches were used to successfully synthesize Co3O4 nanomaterials including nanorods, nanosheets, nanotubes, and nanoparticles. The as-prepared samples were characterized by thermogravimetric and differential thermal analysis, x-ray diffraction, transmission electron microscopy, scanning electron microscopy, and Brunauer–Emmett–Teller (BET) surface area measurement, respectively. The photocatalytic degradation properties for methyl orange in simulated waste water using the as-prepared Co3O4 samples were investigated with assistance of hydrogen peroxide under irradiation of visible light. The results revealed that the Co3O4 with different morphologies showed different photocatalytic properties for the degradation of methyl orange. Of the samples, Co3O4 nanotubes and nanosheets exhibited higher photocatalytic activity. The repeat performances of Co3O4 nanotubes and nanosheets were measured, respectively. The results verified that the Co3O4 nanotubes and nanosheets all exhibited excellent repeatability for the catalytic degradation of methyl orange.

Synthesis and photocatalytic application of ZnO nanoarrows

We report a simple and efficient route to synthesize nanoarrows shaped zinc oxide (ZnO) combining electrospinning and high temperature calcination for photocatalytic applications. A comparison of the photo catalytic degradation of methyl orange with ZnO nanoparticles showed that the ZnO nanoarrows were superior to ZnO nanoparticles. These novel ZnO nanoarrows could have wide range of applications such as energy materials, gas sensors, UV–visible blockers and catalyst for organic synthesis.

Microwave Enhanced Catalytic Degradation of Methyl Orange in Aqueous Solution over CuO/CeO2Catalyst in the Absence and Presence of H2O2

This work focuses on the microwave enhanced catalytic degradation of methyl orange (MO) in aqueous solution over CuO/CeO2 catalyst in the absence and presence of H2O2. The prepared CuO/CeO2 catalysts were characterized with X-ray diffraction, Brunnauer-Emmett-Teller analysis, temperature-programmed reduction, and temperature-programmed desorption techniques to elucidate the effect of calcination temperature on its properties and catalytic performance. The results show that calcination temperature exerts remarkable influence on the catalytic performance of CuO/CeO2, with that calcined at 300 °C displaying the highest MO degradation ability. On the basis of Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy measurement results, the mechanism of MO degradation under microwave irradiation in the presence of both CuO/CeO2 and H2O2 was suggested. A synergistic rather than additive effect of catalyst, microwave irradiation, and H2O2 contributes to the high degradation activity toward MO.

Effect of Graphene in Enhancing the Photo Catalytic Activity of Zirconium Oxide

Graphene, have two-dimensional structure with high conductivity, extremely high specific surface area and superior electron mobility etc. It has been regarded as an important synthesis material for various composite materials used in many applications. Especially, graphene-based semiconductor photo catalysts have attracted extensive attention because of their usefulness in environmental applications such as air cleanup, water disinfection, hazardous waste remediation, and water purification. The present study involves the photo catalytic degradation of methyl orange by photo catalytic process using different concentrations of ZrO2/graphene synthesized at different annealing temperature. A series of zirconium oxide (ZrO2, zirconia) and graphene (Gr) composites with different contents of Gr (5.7, 7.3, 8.3 %) in the composite were synthesized using zirconium oxychloride (ZrOCl2·8H2O) and graphene oxide as the starting materials. The photocatalytic activities of the synthesized composites were measured for the degradation of methyl orange dye with UV spectroscopy. The rate of decolorization was recorded with respect to the change in intensity of absorption peaks for methyl orange. The absorption peaks, diminished and finally disappeared during reaction, indicating that the dye had been degraded. The photocatalytic activity is strongly affected by the concentration of graphene in the ZrO2. The synthesized ZrO2/graphene photocatalysts are characterized by X-ray diffraction, TGA, Raman spectroscopy and UV–Visible spectroscopy. Finally, it has been concluded that graphene when employed as catalytic support for ZrO2 boost its photo catalytic efficiency. Effect of graphene on photo catalytic activity of ZrO2 anneal at 1,000 °C.

Au@TiO2 nanocomposites for the catalytic degradation of methyl orange and methylene blue: An electron relay effect

Au@TiO2 nanocomposites were used for the catalytic degradation of methyl orange and methylene blue by NaBH4. A detail pathway for step by step reduction, oxidation and complete mineralization of intermediates into the respective end-products was established by UV–vis spectroscopy, chemical oxygen demand, ion chromatography and cyclic voltammetry (CV). CV studies confirmed that the dyes were reduced and oxidized to the end-products by NaBH4 in the presence of Au@TiO2 nanocomposites and O2, OH and HO2 radicals generated in situ. Results suggest that Au@TiO2 nanocomposites not only assist in the decolorization of dyes, but also promote their complete mineralization into harmless end-products.

Synthesis and Dye Degradation Properties of Cu2+ Complexes with Benzimidazole Derivatives

Six benzimidazole derivatives were synthesized and charactrized by IR spectra, 1H-NMR spectra and MS spectra. The coordination reaction of the derivatives with CuCl2. And six novel Cu (II) complexes with the derivatives were prepared and characterized by UV spectra, IR spectra and elemental analysis. The catalytic degradation of methyl orange aqueous solution was investigated using the complexes as catalysis in presence H2O2 by HPLC method and Vis-spectrophotometry. The result of characterization showed that there are four coordination sites around Cu (II) in all complexes, which are respectively occupied by one sulfur atom (from the derivative), one nitrogen atom (from the derivative), one oxygen atom ( from the OH-) and one chlor atom (from the Cl-). The degradation of methyl orange indicated that all the complexes show the properties of enzyme activity. And the main degradation products determined were hydroquinone and maleic acid.

Laboratory Scale Unit for Photocatalytic Removal of Organic Micropollutants from Water and Wastewater. Methyl Orange Degradation

An innovative laboratory scale unit was used to carry out UV photoinduced catalytic degradation of methyl orange. For this purpose, the experimental system was made of a bottom and an upper reservoir (∼120 L each) which were connected by an inclined channel through which water was recirculated. TiO2 (Anatase) was deposited (∼10–2 mg/cm2) at the bottom of the connecting channel while the Methyl Orange solution was exposed to the UVB radiation (λ ≈ 300 nm) during its recirculation through the connecting channel.The unit was first characterized from both the hydrodynamic and the hydraulic points of view. Photodegradation kinetics were followed by UV–vis absorption measurements of the residual methyl orange solution concentration along time, and the synergic effect of the catalyst and the intensity of the UV radiation in promoting degradation of the substrate was demonstrated. The abatement efficiency of the UV/TiO2 system toward methyl orange was evaluated in the concentration range 0.3–8.5 mg/L. Kinetic patterns were described by first (or pseudofirst) order theoretical models up to the concentration of 0.7 mg/L, whereas at higher concentrations kinetic trends were better described by zero-order models independently from the substrate concentration in the liquid-phase. The proposed solution, after an upscale field investigation, may represent a valuable alternative to the methods conventionally used for the abatement of textile dyes from wastewater, that is, water clarification, reverse osmosis, activated carbon sorption, and biosorption.

Visible Light Catalytic Degradation of Methyl Orange in Aqueous Solution by Bi4TaO8X (X=Cl, Br, I)

Bi-based oxyhalide Bi4TaO8X (X=Cl, Br, I) photocatalysts have been prepared by the combined method of liquid phase and solid state reactions and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Using the azo dye wastewater simulated by aqueous methyl orange (MO) solutions, photocatalytic activity of these catalysts was studied under ultraviolet light, visual light, and solar irradiation. All of the samples had high photocatalytic activity. After 2 h of ultraviolet radiation, the degradation efficiency of methyl orange by Bi4TaO8X (X=Cl, Br, I) was as high as 100%. Under visible-light and solar irradiation, the photocatalytic activity decreased in the order Bi4TaO8I>Bi4TaO8Br>Bi4TaO8Cl. More than 90% degradation efficiency was observed for Bi4TaO8I after 12 h of solar irradiation. Furthermore, the photocatalytic degradation kinetics of methyl orange have been investigated under different types of light irradiation.

Catalytic decoloration of methyl orange solution by nanoporous metals

Nanoporous Au exhibits catalytic degradation of methyl orange (MO) solution while its counterpart, bulk Au, does not. Other nanoporous metals such as Pd and Ni also exhibited the catalytic MO degradation. Because the degradation occurred under dark conditions, it is clearly distinguished from photocatalytic degradation conventionally observed in TiO2 and ZnO.

Preparation of the Modified Mesoporous Beta Materials and its Application in Wet Catalytic Degradation of Methyl Orange

The heterogeneous beta-supported transition metal catalysts were prepared by incipient wetness impregnation. The catalytic oxidation degradation of methyl orange was carried over the heterogeneous catalyst in the peroxide catalytic oxidation process. The pure beta materials showed quick adsorption equilibrium characterization, and the adsorption ratio was only 30%. Compared with the adsorption of the pure beta carrier, the Cu/beta and Fe/beta catalyst could effectively degrade methyl orange with high catalytic activity and easy catalyst separation from the solution using hydrogen peroxide as oxide. The methyl orange removal efficiency could reach 99% in the optimum experimental conditions. The optimal mental content for Cu, Ag, Mn, Fe and Co was 5%, 8%, 0.3%, 1% and 0.3%, respectively.

Preparation and Characterization of Fe<sup>3+</sup> / TiO<sub>2</sub> Thin Films Loaded Activated Carbon and Degradation of Methyl Orange

Sol - gel method and doped with Fe3+ modification techniques were used, prepared for high catalytic activity of iron-doped titanium dioxide nanoparticles,which loaded on the activated carbon for Degradation of Methyl Orange. Such as crystal structure, particle size, load morphology, chemical state and optical absorption characteristics of the doped titania nanoparticles were characterized by using XRD, SEM, and UV-Vis. Fe-TiO2 catalysts for visible light response and the catalytic degradation of methyl orange in water performance were studied. The results showed that: catalysts prepared were anatase, the particle size decreases with the more amount of iron-doped. The phenomenon of Fe3+-modified TiO2 red shift were obviously. Compared with the undoped catalyst,degradation of Fe3+-TiO2 containing activated carbon improved significantly both in the UV and fluorescent light.

Seed-mediated synthesis of polyhedral 50-facet Cu2O architectures

Highly symmetric polyhedral 50-facet Cu2O homogeneous structures enclosed by 24 high-index {211} facets, and 8 low-index {111} facets, 6 low-index {100} facets and 12 low-index {110} facets have been synthesized via a facile seed-mediated solution phase route. The formation of these polyhedral architectures not only provides an innovative approach to design and synthesize more and more novel polyhedral shapes to further enrich the current morphologies of Cu2O crystals, but also offers a good opportunity to understand the fundamental significance of high-index facets for enhancing the catalytic degradation of methyl orange.