Activity For Degradation Of Methyl Orange Research Articles

Dual Z‐scheme ternary heterojunction photocatalyst with enhanced visible‐light photocatalytic degradation of organic pollutants

AbstractPhotocatalysis technology driven by solar energy is considered to be promising for solving energy crisis and environmental problems. Graphitic carbon nitride has been widely researched in the photocatalysis field due to its suitable band positions, non‐toxicity, easy synthesis, high stability, and low cost. However, the slow separation and rapid recombination of photogenerated carriers, the poor visible light response and the low specific surface area seriously limit the photocatalytic activity of g‐C3N4. Here, firstly, g‐C3N4 nanosheets with a large specific surface area of 152.2 m2 g−1 which provide more surface‐active sites for photocatalysis were prepared by secondary calcination method. Next, MoS2 and metal–organic framework (MIL‐101(Cr)) were tightly bonded on g‐C3N4 nanosheets to form ternary g‐C3N4/MoS2/MIL‐101(Cr) heterojunction photocatalyst. In which, a ternary dual Z‐scheme heterojunction photocatalyst composed of g‐C3N4, MoS2, and MIL‐101(Cr) was constructed to facilitate the separation and the migration of photogenerated charges. At the same time, MoS2 enhanced the visible light response of the ternary photocatalyst. The optimal ternary photocatalyst displayed the highest activity for methyl orange degradation (degradation efficiency of 98% in 60 min) under visible light irradiation. Finally, a photocatalytic mechanism of a dual Z‐scheme electron transfer channel and h+‐·O2− double oxidation sites were proposed and discussed.

Minimalist preparation and photocatalysis properties of a spinyball-like indium-based composite suitable for different light conditions

The CdIn2S4/In2S3/CaIn2S4 composites were successfully prepared by an extremely simple programmed temperature hydrothermal method, which present a spinyball-like structure with a micro-sphere diameter of about 2.5–3 µm. X-ray diffraction analysis (XRD) results show that CaIn2S4 and CdIn2S4 exist in the form of cubic phase, and In2S3 exists in the form of cubic β-In2S3 in the composites. By discussing the relationship between the change of strain gravity and the change of cell parameters of CaIn2S4 after compounding In2S3 and CaIn2S4, the effects of crystal lattice change, crystal face growth and inhibition on the photocatalytic activity were studied. Meanwhile, through the photoluminescence spectra (PL), electrochemical impedance spectra (EIS), and transient photocurrent response analysis, the recombination of CaIn2S4, In2S3, and CdIn2S4 can accelerate the charge transfer and inhibit the recombination of electron–hole pairs in the CdIn2S4/In2S3/CaIn2S4 composites, so that higher photocatalytic performance can be obtained. Using methyl orange (MO) as the degradation object, the photo-degradation properties of the as-composites were studied and compared, and the results show that spinyball-like In2S3/CaIn2S4 and CdIn2S4/In2S3/CaIn2S4 exhibit high photocatalytic activity for degradation of MO under visible light and simulated sunlight, respectively. Furthermore, with Pt loaded as a co-catalyst, in Na2S aqueous solution, the hydrogen production rate of CdIn2S4/In2S3/CaIn2S4 photocatalysts is 74.9 μmol·g−1 (8 h), which is 8 times that of the commercially available TiO2. Furthermore, based on the results of the trapping experiment of CdIn2S4/In2S3/CaIn2S4, a possible photocatalytic mechanism was proposed, and the effect of multi-path photo-generated electron migration in the photocatalytic process was explained.

Structural, optical and photocatalytic properties of LaTi0.4Mg0.4Fe0.2O3 perovskite prepared by high-energy ball milling

The LaTi0.4Mg0.4Fe0.2O3 perovskite was synthesized using a mechanochemical process followed by high-temperature annealing at 600 and 800 ​°C. The effects of milling time and annealing temperature on structural, microstructural changes and optical properties were examined. The photocatalytic activity of LaTi0.4Mg0.4Fe0.2O3 perovskite was evaluated through the photodegradation of methyl orange and methylene blue dyes under UV light irradiation. The results showed that the annealing temperature performed an important role in the crystallite size, crystalline degree, photoluminescence, and band gaps of the LaTi0.4Mg0.4Fe0.2O3 samples. The temperature of annealing had a profound influence on the photocatalytic activities of the LaTi0.4Mg0.4Fe0.2O3 perovskite in the single and binary dye system. The highest photocatalytic activity for methyl orange degradation showed the LaTi0.4Mg0.4Fe0.2O3 annealed at 800 ​°C, while not annealed sample, show the highest activity for degradation of methylene blue. The maximum efficiency of methylene blue photodegradation in individual and binary mixtures was observed over non-annealed perovskite at the same irradiation times. The photodegradation of methylene blue and methyl orange on the LaTi0.4Mg0.4Fe0.2O3 followed a pseudo-first-order kinetic process.

Nitrogen and Sulfur Quantum Dot Co-Modified Graphene Nanosheet with Enhanced Photocatalytic Activity for Methyl Orange Degradation

Nitrogen-sulfur quantum dot co-modified graphene nanosheets composites (NSG) were fabricated via a facile hydrothermal method as a high performance metal-free catalyst for methyl orange (MO) degradation. Physical-chemical properties of the obtained samples were characterized by XRD, FTIR, SEM, TEM, EDX, TGA, BET, and UV–Vis DRS technologies. Compared with RGO, NSG exhibited much better photocatalytic performance for MO degradation under visible light, especially, NSG(30) showed the best photocatalytic degradation rate of 100% within 180 min. XRD, TG, and UV–Vis DRS results demonstrated that the addition of N and S can enhance the stability of oxygen containing functional groups to supply more adsorption active centers for organic contaminant molecular, adjust the band gap to a certain extent and increase the number of photogenerated electrons, improve the visible light utilization rate of the material and thus improve the photocatalytic degradation performance of the NSG composites. The degradation activity of the catalyst remained above 90% after 3 recycles. Finally, a possible photodegradation mechanism of MO on the obtained NSG sample was proposed.

Sol–gel synthesized ZnO/Mn–TiO2 core–shell nanocomposite and its elevated activity for methyl orange degradation

Photocatalysis is a new advanced oxidation process based on the irradiation of semiconductors such as TiO2 and ZnO for photodegradation of contaminants. In this process, the semiconductor absorbs the photon energy of ultraviolet radiation, generating highly reactive species for the degradation of organic compounds. It has been reported that doping of transition metals (e.g., Cu, Ni, Co, and Mn) into the structure of oxide semiconductors can reduce the band gap and expand their adsorption properties to the visible solar spectrum. Accordingly, a new hybrid photocatalyst of Mn-doped TiO2 / ZnO with an Mn content of 1 to 5 wt. % was synthesized via the sol–gel process followed by thermal calcinations in air at 500°C. The prepared photocatalyst powder was characterized in terms of crystalline structure, thermal property, surface morphology, and band gap energy level. Its photocatalytic performance was then assessed based on photodegradation of methylene orange under visible light irradiation. Compared with the pure TiO2 / ZnO, the lattice of Mn-doped TiO2 / ZnO was found to be more thermally stable, and thus phase transformation of anatase to rutile was postponed to a higher calcination temperature. The photocatalysis evaluation showed an increased activity of Mn–ZnO / TiO2 compared with pure TiO2 and TiO2 / ZnO under visible light irradiation. Accordingly, the highest degradation of 98% was obtained by the Mn–ZnO / TiO2 with 3 wt. % Mn.

In situ synthesis and improved photoelectric performances of a Sb2Se3/β-In2Se3 heterojunction composite with potential photocatalytic activity for methyl orange degradation

A series of Sb2Se3/β-In2Se3 heterojunction composites with different contents of β-In2Se3 were successfully synthesized via an in-situ melt-quenching method. The relationship between structure and photoelectric performances was systematically investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, UV–Vis optical absorption, and photoelectrochemical measurement. The direct band energy of the composites was in the range of 1.15–1.18 eV, implying strong visible light harvesting ability. Meanwhile, the number of heterojunctions and the connectivity of β-In2Se3 crystals could be adjusted by changing the content of β-In2Se3. As a result, the optimized composites (Sb2Se3-10% β-In2Se3) exhibited remarkable photocurrent density that was about 283 times higher than that of pure Sb2Se3. Moreover, the response and recovery times were faster than that of previous reported Sb2Se3. The interface charge separation and transport mechanism for the improved photoelectric performances was proposed based on the experimental results. Thanks to the remarkable photocurrent density, a potential application was also evaluated by photocatalytic degradation of MO (Methyl Orange) solution. After 180 min of illumination, 76% of MO dye could been decomposed. This work will provide the direct guidance for constructing Sb2Se3/β-In2Se3 heterojunction devices for harvesting solar energy.

Green and eco-friendly synthesis of Nickel oxide nanoparticles and its photocatalytic activity for methyl orange degradation

In this study the catalytic ability of green synthesized nickel oxide nanoparticles (NiO NPs) is investigated for degradation of methyl orange as a hazardous environmentally contamination in water. The NiO NPs was prepared at ambient conditions using the antioxidant content of Punica granatum L. (pomegranate) juice extract and their bio-reducing ability were studied in details. This process is entirely green process, free from toxic and hazardous solvent. The biosynthesized NiO NPs were in nano scale and their morphology, sizes, surface area and optical properties were characterized using field emission scanning electron microscope (FE-SEM), BET surface area analysis, thermogravimetric analysis, energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD) and ultraviolet–visible spectroscopy (UV–Vis). The biosynthesized NiO NPs were found to be active catalysts, particularly with the reducing agents for instance sodium borohydride, for the degradation of the toxic organic dyes such as methyl orange (MO) in contaminated water. The NiO NPs are stable and reusable for reducing MO to its leuco-form, in a short time, in an aqueous medium in the absence of reducing agents. This method is much cheaper than the other methods. The catalytic activity of NiO NPs can be explained by its small size, compared with the bulk materials, which produce numerous active sites due to its big surface area per unit volume.

The Role of H2C2O4 and Na2CO3 as Precipitating Agents on The Physichochemical Properties and Photocatalytic Activity of Bismuth Oxide

AbstractSynthesis of bismuth oxide synthesis through the precipitation method using H2C2O4 and Na2CO3 precipitating agents, identification of physicochemical properties and its photocatalysis activity for methyl orange degradation were conducted. The bismuth oxide synthesis was undertaken by dissolving Bi(NO3)3.5H2O in HNO3, then added precipitating agents to form precipitate. The results showed that bismuth oxide produced by H2C2O4 precipitating agent was a yellow powder containing a mixture of α-Bi2O3 (monoclinic) and β-Bi2O3 (tetragonal), porous with size of 28-85 μm. Meanwhile, the use of Na2CO3 as precipitating agent resulted in bismuth oxide consisting of α-Bi2O3 and β-Bi2O3 and Bi2O4, irregular shape without pore being 40-115 μm in size. Bismuth oxide synthesized with H2C2O4 precipitating agent showed higher photocatalytic activity compared to bismuth oxide synthesized using Na2CO3 on degrading methyl orange dye with degradation rate constants of 2.35x10-5 s-1 for H2C2O4 and 1.81x10-5 s-1 for Na2CO3.

Preparation of Gd-Doped TiO2 Nanotube Arrays by Anodization Method and Its Photocatalytic Activity for Methyl Orange Degradation

Gd-doped TiO2 nanotube arrays with 3D ordered and high specific surface (176 m2/g) area are successfully prepared on a Ti foil surface via an anodizing method. The characterizations of Gd-doped TiO2 nanotube arrays are carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectrometer (EDX), optical contact angle measurer, and ultraviolet (UV) fluorescence spectrophotometer, respectively. The results reveal that the Gd-doped TiO2 nanotube arrays form on the Ti foil surface with a length of about 50.5 μm and 100 nm in diameter, and the growth direction grown along the (101) direction of anatase crystal. Under the optimized reaction conditions (60 V, 10 h, 0.01mol/L Gd3+), the crystal phase of Gd-doped TiO2 show an excellent nanotube structure, possess a beneficial photocatalytic performance for methyl orange (MO) (Degradation rate was 95.8%) and an excellent hydrophilic property (The optical contact angle was 4.9°). After doping with Gd, the hydrophilic and photocatalytic properties of the TiO2 nanotubes are further improved.

Application of TiO2-Cu Composites in Photocatalytic Degradation Different Pollutants and Hydrogen Production

In the present work, copper nanoparticles were deposited onto the surface of two different commercial titanias (Evonik Aeroxide P25 and Aldrich anatase). During the synthesis, the concentration of copper was systematically varied (0.5%, 1.0%, 1.5%, 5.0%, and 10 wt.%) to optimize the composite-composition. The photocatalytic activity was evaluated under UV-light, using methyl orange and Rhodamine B as model and ketoprofen as real pollutant. For the hydrogen production capacity, oxalic acid was used as the sacrificial agent. The morpho-structural properties were investigated by using XRD (X-ray diffraction), TEM (Transmission Electron Microscopy) DRS (Diffuse Reflectance Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), and SEM-EDX methods (Scanning Electron Microscopy-Energy Dispersive X-ray Analysis). Increasing the copper concentration enhanced the photocatalytic activity for methyl orange degradation in the case of Aldrich anatase-based composites. When the P25-based composites were considered, there was no correlation between the Cu concentration and the activity; but, independently of the base photocatalyst, the composites containing 10% Cu were the best performing materials. Contrarily, for the ketoprofen degradation, increasing the copper concentration deteriorated the photoactivity. For both Aldrich anatase and P25, the best photocatalytic activity was shown by the composites containing 0.5% Cu. For the degradation of Rhodamine B solution, 1.5% of copper nanoparticles was the most suitable. When the hydrogen production capacity was evaluated, the P25-based composites showed higher performance (produced more hydrogen) than the Aldrich anatase-based ones. It was found that Cu was present in four different forms, including belloite (Cu(OH)Cl), metallic Cu, and presumably amorphous Cu(I)- and Cu(II)-based compounds, which were easily convertible among themselves during the photocatalytic processes.

Hydrothermal route to synthesize helical CdS@ZnIn2S4 core-shell heterostructures with enhanced photocatalytic hydrogeneration activity

In this work, one-dimensional CdS@ZnIn2S4 helical core-shell heterostructures consisting of homogeneous CdS nanorods (NRs) decorated with ZnIn2S4 nanosheets (NSs) were fabricated by hydrothermal method. Morphology observations reveal that ZnIn2S4 nanosheets were uniformly wrapped on the surface of CdS NRs, which not only offers favorable interfacial contacts to depress the recombination of photo-generated holes and electrons, but also provides protective shield for CdS NRs to avoid serious photo-corrosion. The photocatalytic activities of the as-prepared CdS@ZnIn2S4 heterostructured nanocomposites were investigated towards photochemical syntheses from 4-nitroaniline (4-NA) to corresponding 4-phenylenediamine (4-PDA), meanwhile the CdS@ZnIn2S4–90 sample exhibits excellent ability for photocorrosion resistance during the recycling catalytic reaction for 4-NA reduction. Also, the resulting CdS@ZnIn2S4 nanocomposites display the enhancement of photocatalytic activity for methyl orange degradation. The possible mechanism of enhanced photocatalytic activity was proposed on the basis of the construction of intimate heterogeneous interface and the matched band alignment in CdS@ZnIn2S4 hybrid system. We hope that this simple yet novel strategy to prepare helical CdS@ZnIn2S4 core-shell heterostructures could provide a new sight in design and fabrication of efficient and stable sulfide based nanocomposites for photocatalytic application.

Synthesis of NiFe2O4-LDH Composites with High Adsorption and Photocatalytic Activity for Methyl Orange Degradation

The presence of hazardous chemicals in wastewater produced by industrial activities and human metropoles is threating the availability of safe drinking water. The development of a multifunctional material coupling adsorption and photocatalytic activity is hereby particularly promising for the removal of pollutants. We have proved the adsorption and catalytic activity of NiFe2O4-layered double hydroxide (LDH) composite through the degradation of methyl orange (MO) at room temperature under visible light. This degradation is enhanced by using a set of small light-emitting diodes (LEDs) providing a uniform 405 nm UV light. The remediation process is based on a first-step rapid adsorption of MO molecules by the LDH structures followed by the photocatalytic oxidation of the pollutant by the (·OH) radicals produced by the NiFe2O4 semiconductor nanoparticles (NPs). The magnetic properties of the ferrite NPs allow a facile separation of the composite from the liquid media via a simple magnet. NiFe2O4-LDH composite could find wide application as a highly effective adsorbent/oxidizing catalyst operating under visible or near UV light.

Plasmon-resonance-enhanced visible-light photocatalytic activity of Ag quantum dots/TiO2 microspheres for methyl orange degradation

We successfully prepared Ag quantum dots modified TiO2 microspheres by facile solvothermal and calcination method. The as-prepared Ag quantum dots/TiO2 microspheres were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The Ag quantum dots/TiO2 photocatalyst showed excellent visible light absorption and efficient photocatalytic activity for methyl orange degradation. And the sample with the molar ratio of 0.05 (Ag to Ti) showed the best visible light photocatalytic activity for methyl orange degradation, mainly because of the surface plasmon resonance (SPR) effects of Ag quantum dots to generate electron and hole pairs for enhanced visible light photocatalysis. Finally, possible visible light photocatalytic mechanism of Ag quantum dots/TiO2 microspheres for methyl orange degradation was proposed in detail.

Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts

As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2. Under visible light irradiation, the PDs-TiO2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO2 is 3.6 and 9.5 times higher than that of pure TiO2 and commercial P25, respectively. In addition, the PDs-TiO2 exhibit good recycle stability under UV–Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO2, therefore contribute to the excellent photocatalytic activity.

Oxygen vacancies induced by zirconium doping in bismuth ferrite nanoparticles for enhanced photocatalytic performance

Doping with certain foreign metal ions in a photocatalyst might introduce surface defects (such as extrinsic oxygen vacancies), which can probably play an important role in the photocatalytic performance. In this work, oxygen vacancies were for the first time introduced into bismuth ferrite (BiFeO3, denoted as BFO) nanoparticles by zirconium (Zr) doping, and the relationship between oxygen vacancies and the photocatalytic activity of Zr-doped BFO was investigated. It was found that the optical properties and the photocatalytic activities of Zr-doped BFO photocatalysts were significantly affected by the Zr doping amount. The Zr-doped BFO photocatalysts showed much higher photocatalytic activities for methyl orange degradation or Cr(VI) reduction than the pristine BFO. When the Zr doping content was 2mol%, the highest photocatalytic efficiency was achieved, which was more than two times that of the pristine BFO. The boosted photocatalytic performance of Zr-doped BFO was mainly attributed to the presence of surface oxygen vacancies induced by Zr doping, which could act as electron traps and active sites to promote the efficient separation and migration of photogenerated charge carriers, as verified by the trapping experiments and the photoelectrochemical measurements. Thus, the present work provides a simple approach to introduce oxygen vacancies in semiconductor photocatalysts through metal ion doping with a great potential for development of efficient visible light photocatalysts, and also enlarges the understanding of surface-defect dependence of photocatalytic performance for environmental remediation.

Spray drying assisted assembly of ZnO nanocrystals using cellulose as sacrificial template and studies on their photoluminescent and photocatalytic properties

The conventional zincoxen cellulose solution, which was obtained by dissolving cellulose with the zincoxen solvent (tri(ethylenediamine) zinc hydroxide solution, Zn(EDA)32+), has been used as raw materials for the preparation of zincoxen/cellulose complex microspheres via a spray drying technique. The obtained zincoxen/cellulose microspheres are turned into assemblies (or clusters) of ZnO nanocrystals by calcining the complex microspheres at 500 or 700°C. For the preparation, zincoxen plays both the role as solvent for cellulose and precursor for the ZnO nanocrystals. While, the cellulose acts as assembly agent during the spray drying step and sacrificial templates in the calcinations process. The content of cellulose in the zincoxen cellulose aqueous solution and the calcination temperature show significant impacts on the morphology, porosity, optical properties and photocatalytic activity of the resulted ZnO nanocrystal assemblies. The structures, morphology and porosity have been investigated based on XRD, SEM, TEM and N2 adsorption-desorption technique. The lattice parameters have been fitted by the Rietveld refinement and the strains in the crystals have been studied. Under ultraviolet light irradiation, all the assemblies of ZnO nanocrystals exhibit high photocatalytic activity for methyl orange degradation in aqueous solution and also satisfied reusability and stability of morphology and composition.

Enhanced Photocatalytic Performance under Visible and Near-Infrared Irradiation of Cu1.8Se/Cu₃Se₂ Composite via a Phase Junction.

A novel Cu1.8Se/Cu3Se2 composite photocatalyst was prepared by the simple precipitation method. This composite possesses a wide photoabsorption until the range of near-infrared light, and exhibits significantly enhanced photocatalytic activity for methyl orange degradation under visible and near-infrared light irradiation compared with bare Cu1.8Se and Cu3Se2. The mechanism of this outstanding photocatalytic behavior can be explained by the calculated energy band positions. The efficient charge separation via a phase junction of Cu1.8Se/Cu3Se2 composite would make a great contribution to its much-enhanced photocatalytic efficiency.

Photocatalytic self-cleaning cotton fabrics with platinum (IV) chloride modified TiO2 and N-TiO2 coatings

To enable photocatalytic self-cleaning cotton fabrics working under visible light irradiation, platinum (IV) chloride modified TiO2 (Pt-TiO2) and N-TiO2 (Pt-N-TiO2) nanosols are synthesized through a low temperature precipitation-peptization method. According to the characterizations of XRD, DRS and TEM, all nanoparticles are anatase nanocrystallites in the sizes of less than 10nm, while N-TiO2 nanoparticles have better crystallization and smaller sizes. However, the cotton fabrics functionalized with Pt-TiO2 display significantly enhanced photocatalytic activity for methyl orange degradation and coffee stain removal under both solar simulator and visible light irradiation, while the performance of that coatings of Pt-N-TiO2 is poor. Further XRF and XPS results indicate that surface species on N-TiO2 block the adsorption of PtCl62− anions, whereas these anions strongly attach on the surface of TiO2 nanoparticles, and accordingly enable functionalized cotton fabrics efficient visible light driven activities based on a mechanism of charge transfer from ligand to metal (CTLM) excitation.

Synergistic effect on the photocatalytic activity of N-doped TiO2 nanorods synthesised by novel route with exposed (110) facet

This paper describes a facile route for the preparation of visible-light-active N-doped TiO2 nanorods arrays at low temperature by a template-free oxidant peroxide method (OPM) and crystallized under hydrothermal treatment. The samples were characterized for structural, morphological and optical properties by XPS, FE-SEM, HRTEM, XRD, Raman and UV–vis spectroscopy. XPS analysis revealed that N dopant atoms were mainly added at the interstitial sites into TiO2 lattice structure and few N atoms were present as substitutional sites of nitrogen atoms and/or at molecularly chemisorbed γ-N2 molecules. FE-SEM and HR-TEM analyses show that doping does not influenced the cylindrical architecture of the nanorods. However, N doping causes an obvious red shift in the band edge which increases visible region absorption. The photocatalytic activity of pristine and N-doped TiO2 photocatalysts was tested for the degradation of methyl orange (MO) under UV and visible light irradiation. The N-doped TiO2 photocatalysts showed an efficient photocatalytic activity for methyl orange degradation under UV and visible-light irradiation as compared to pristine TiO2. Multiple cycles for the MO photodegradation were performed without a decrease in the photocatalytic activity. PEC studies showed that photocurrent densities of 8.2 μA cm−2 and 7.0 μA cm−2 were obtained under UV and visible-light illumination at a potential of 0.8 V.

Efficient removal of dye from an aqueous phase using activated carbon supported ferrihydrite as heterogeneous Fenton-like catalyst under assistance of microwave irradiation

Ferrihydrite (Fh) stabilized inside porous activated carbon (Fh/AC) was prepared and used as a heterogeneous Fenton-like catalyst for oxidative degradation of methyl orange (MO) in simulated dye wastewater. The prepared catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and N2 adsorption–desorption isotherm. It was found that ferrihydrite was highly dispersed on the surface of pretreated AC and the as-prepared Fh/AC exhibited catalytic activity for degradation of MO in the Fenton-like system consisting of solid catalyst, hydrogen peroxide (H2O2) and MO solution. With the assistance of microwave (MW) irradiation, the degradation efficiency of MO was significantly enhanced, indicating a synergetic effect of MW and Fenton-like system. The initial pH value of MO solution exerted notable influence on the reaction and acidic condition is more favorable to the degradation of MO. The recyclability of the catalyst was also evaluated by successive batch experiments under optimum conditions.