Decomposition Of Orange Research Articles

Effect of Etching Condition on Nanoporous Structure and Methyl Orange Decomposition of Fe-Si-B Metallic Glass

Effect of Etching Condition on Nanoporous Structure and Methyl Orange Decomposition of Fe-Si-B Metallic Glass

The activation of peroxymonosulfate via oxygen/cobalt-modified carbon nitride for decomposition of acid orange 7: role of high-value cobalt and superoxide radical

The activation of peroxymonosulfate via oxygen/cobalt-modified carbon nitride for decomposition of acid orange 7: role of high-value cobalt and superoxide radical

Rational construction of carbon quantum dots-zinc cobalt oxide heterostructure as bifunctional catalyst for oxygen evolution reaction and wastewater treatment

Semiconductor photocatalysts are promising for Oxygen evolution reaction (OER) and also for reducing organic pollutants in wastewater. However, their limited activity under UV light and the fast recombination of electron-hole pairs, hinder their utilization in wastewater treatment. To address these challenges a novel photocatalyst based on carbon quantum dots (CQDs) supported Zinc–Cobalt Oxide (ZnCo2O4) was developed, which demonstrated enhanced photocatalytic efficiency. Experimental findings indicated that 0.7 CQDs/ZnCo2O4 exhibited superior photocatalytic performance compared to ZnCO2O4 and CQDs/ZnCO2O4 composites materials, achieving over 100 and 96 % decomposition of methylene blue (MB) and methylene orange (MO) dyes after 50 and 140 min under UV light. The enhanced performance of 0.7 CQDs/ZnCo2O4 can be attributed to the charge transfer rate and synergistic effect between the coupled CQDs and ZnCo2O4. Moreover, studies with radical scavengers reveal that •O2, •OH, and h+ play crucial roles in the breakdown of MB and MO dyes. Furthermore, 0.7 CQDs/ZnCo2O4 displayed very low overpotential of 220 mV at 100 mA cm−2 for OER activity with a robust durability for 250 h at 500 mA cm−2.

Highly efficient ZrO2 photocatalysts in the presence of UV radiation synthesized in a very short time by plasma electrolytic oxidation of zirconium

We demonstrated in this paper that plasma electrolytic oxidation of zirconium in an alkaline electrolyte (10 g/L trisodium phosphate decahydrate) with the addition of NaAlO2 is a highly efficient method for obtaining ZrO2 coatings that are effective photocatalysts for the decomposition of organic pollutants under UV irradiation. ZrO2 coatings were formed by varying the PEO time from 60 s to 600 s, the NaAlO2 concentration up to 4 g/L, and characterized by SEM/EDS, XRD, XPS, DRS, and photoluminescence spectroscopy. Methyl orange decomposition was used to examine the photocatalytic activity (PA) of ZrO2 coatings. The PA of the formed PEO coatings is determined by the ratio of monoclinic and tetragonal ZrO2 phases, as well as the content of incorporated Al3+ in the crystal structure of ZrO2. Al3+ incorporated into ZrO2 coatings improves tetragonal phase stability by causing the formation of oxygen vacancies, which is crucial for enhancing their PA. Furthermore, the Al3+ dopant serves as a capture site for photo-induced electrons, inhibiting electron/hole recombination. The best PA was demonstrated by the ZrO2 coating formed after 60 s in an alkaline electrolyte with 4 g/L NaAlO2 addition, which contains the most tetragonal ZrO2 phases (around 51.3 %) and Al (around 3.14 at. %) of all formed ZrO2 coatings. After 8 h of irradiation, the PA of this coating was approximately 95 %.

Development of a Sustainable Tungsten and Iron Bimetal-Immobilized SBA-15 Composite for Enhanced Wet Catalytic Oxidation of Dye Capacity.

In this study, wet catalytic decomposition of Orange (II) dye was carried out with tungsten and iron bimetal-incorporated mesoporous SBA-15 (W-Fe@SBA-15) under visible light. The synthesized hybrid composite material was characterized by physicochemical methods, powder X-ray diffraction (PXRD) spectroscopy, scanning electron microscopy combined with energy-dispersive X-ray (SEM-EDX) spectroscopy studies, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and surface property studies to understand the nature of the dye degradation process and for catalytic studies. The maximum degradation of Orange (II) dye measured by a UV-visible spectrophotometer was 99% at a contaminant volume of 2.7 × 10-4 mol/L and a catalyst quantity of 2 g/L in 140 min reaction time. Using gas chromatography-mass spectrometry (GC-MS), the final products were chemically identified. The mechanistic steps of the process were carried out through a series of experiments. The recyclability of the catalyst added a novel feature for such a heterogeneous catalysis that can reduce secondary pollutants in water with no leaching effect observed.

Europium-doped MnO2 nanostructures for controlling optical properties and visible light photocatalytic activity

Pure and europium (Eu) doped manganese oxide (MnO2) photocatalysts were produced using a simple sol-gel technique, and their physical, anatomical, and optical characteristics were extensively studied by means of XRD, TEM, EDAX, Raman, UV, PL, and N2 adsorption-desorption analysis. The energy band gap and degree of crystallinity of Eu-doped MnO2 changedwith the presence of Eu. The Eu-doped MnO2 XRD pattern revealed a hexagonal surface morphology with an typical particle size of 30 nm. The occurrence of trivalent europium and its effective doping into the crystalline structure of MnO2 matrix were validated using the EDS method. The catalytic efficiency of Eu-doped MnO2 for methyl orange decomposition was investigated. Under infrared spectrum, photocatalytic studies revealed that phenol was degraded over a Eu doped MnO2 sample in 100 min (464 nm). The enhanced photocatalytic response by Eu doping was also thoroughly addressed.

Uniform Fabrication of Hollow Titania Using Anionic Modified Acrylated Polymer Template for Phase Composition Effect as Photocatalyst and Infrared Reflective Coating

Polymer coatings containing thermal blocking and near-infrared (NIR)-reflective pigments have received much attention for their potential applications in energy-saving fields. A drawback of these coatings is sustainability providing similar long-term performance. Surface cleaning is mandatory to remove contaminants that decrease reflectance. In this study, synthesized hollow titania as photocatalyst was used to impart anti-contamination to infrared (IR)-reflective coatings. A TiO2 shell was selectively formed on an anionic polystyrene core, modified by methacrylic acid. According to sintering temperature, the enhancement of light absorption ability and photocatalytic activity as methyl orange decomposition was observed with phase composition change. The methylene blue decomposition reaction, reflectance measurement, and measuring thermal profiling of coated steel confirmed the manifestation of hollow particles to dust degradation characteristics and the enhancement of reflection and thermal shielding.

Low-cost nanoparticulate oxidation catalysts for the removal of azo and anthraquinic dyes.

This study aimed to test the activity of Mn ferrite, hematin-Mn ferrite and colloidal maghemite in decomposition of Orange II (O-II) and Alizarin Red S (ARS) in model aqueous solutions. Color removal was explored at room temperature using magnetic stirring with and without a magnetic bar, taking advantage of the solids' magnetism. Decomposition of H2O2 was also studied separately and as radicals provider in dye decomposition. Catalyst/dye solution was fixed at 10mg/4mL. pH and dye concentration were variable. Absorbance was measured during 120min by UV-Vis. Reuse of catalysts was also performed. Azo dyes such as O-II are more resistant to oxidative removal using hydrogen peroxide than anthraquinone-like ARS. CITMD5 reduced ARS absorbance up to 71.9% when dye was less than 250mg/L. HEM-Mn-MAG completely decolorized a 62.5mg/L O-II solution at pH11 while CITMD5 reached half of that conversion under the same conditions. The highest color removal in O-II/ARS mixtures was obtained with HEM-Mn-MAG, 40% absorbance reduction in 2h. Mn-MAG is not active to remove O-II in presence of hydrogen peroxide in the 3-9 pH range at rt. The high activity of Mn-MAG in hydrogen peroxide decomposition may be assigned to the combination of Mn+2/Mn+3 and Fe+2/Fe+3, because the MnOx is active in the decomposition of hydrogen peroxide. Mn-MAG can be reused, preserving high activity in this reaction. Mn-based magnetic nanoparticles should be considered as inexpensive materials to treat textile wastewaters. The online version contains supplementary material available at 10.1007/s40201-021-00640-x.

Synthesis of Cerium Ion Doped Ti-SBA-15 Catalysts and Their Photocatalytic Activity.

Ti-SBA-15 catalysts doped with cerium ion were synthesized using conventional hydrothermal method and they were characterized by XRD, FT-IR, DRS, BET and PL. We also examined the activity of these materials on the photocatalytic decomposition of orange II. Ti-SBA-15 catalysts doped with cerium ions maintained the mesoporous structure regardless of the doping amount of cerium ion. 5 mole% Ce/Ti-SBA-15 catalysts showed the highest photocatalytic activity on the decomposition of orange II, however, the catalysts doped with less than 3 mole% Ce/Ti-SBA-15 showed lower activity compared to pure Ti-SBA-15 catalyst. The PL peaks appeared at about 410 nm at all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of orange II.

Application of X-Ray Methods for Determining the Dimensions of Nanoparticles in the Nanosized Anatase–Poly(N-vinylcaprolactam) System

Nanocomposites prepared by mechanical mixing with grinding and mechanical activation of a mixture of Hombifine N with nanosized anatase (NA) and poly(N-vinylcaprolactam) (PVCL) polymer (PVCL25 and PVCL40 polymers were obtained by drying a PVC aqueous solution at 25 and 40°C, respectively) in different weight ratios have been studied by wide-angle X-ray scattering (WAXS) and (for the first time) small-angle X-ray scattering (SAXS). Amorphization of anatase (decrease in the average size of the coherent-scattering region), selection of X-ray amorphous hydrated titanium dioxide from the amorphous shell of anatase nanoparticles, destruction of PVCL, and disordering of its heterocycles in NA/PVCL (NA : PVCL = 1 : 1) nanocomposites upon mechanical activation have been revealed. The interaction (with water molecule exchange) between anatase, anatase, and PVCL nanoparticles during formation of NA/PVCL25 (NA : PVCL = 1 : 2) upon mechanical mixing with grinding is found to lead to segregation of anatase nanoparticles into two groups: particles with reduced and enhanced (formation of texture) degree of crystallinity (average sizes of coherent-scattering regions) in comparison with the initial anatase. SAXS made it possible to reveal structural inhomogeneities of different sizes in PVCL25 and PVCL40, which change differently upon mechanical activation, retaining the tendency to smaller sizes in PVCL25 (a coil) in comparison with PVCL40 (a globule). It is shown that the effects of mechanical activation and mechanical mixing with grinding on the components of NA–PVCL system differ, and that anatase nanoparticles play a decisive role in NA/PVCL nanocomposites, facilitating averaging of the inhomogeneity sizes upon mechanical activation. The results of studying the photocatalytic activity in the reaction of methyl orange decomposition (UV irradiation) in the presence of NA–PVCL samples indicate that it depends on the average sizes of coherent-scattering regions and is independent of the inhomogeneity sizes.

Morphology Adjustment of TiO2 Nanostructures for Enhanced Photocatalytic Properties

Titanium dioxides (TiO2) nanoarchitectures including microspheres surrounded by nanosheets were synthesized using simple, quick and effective hydrothermal method with moderate temperature (150 °C). We systematically investigated how reaction time affected final morphologies of TiO2. At reaction times equal to 4 and 8 hours (named as TS-4 and TS-8, respectively), TiO2 formed with morphology of irregular microspheres. At longer reaction times (12 hours, named as TS-12), urchin-like TiO2 nanocrystals formed. Photocatalytic activities of the formed TiO2 with different morphologies were evaluated against decomposition of methylene orange and blue (MO and MB, respectively) as well as rose-bengal (RB). Urchin-like TiO2 demonstrated high degradation ratio similar to the commercial catalyst PS 25 on MO (96%). Degradation ratios of samples synthetized for 4 and 8 hours were much lower: 60 and 80%, respectively. During 30 minutes reaction time, TiO2 with urchin-like morphology showed much higher selectivity towards neutralization of MB (99.5%) than towards MO (73%) and RB (88.7%).

Post-Synthetic Derivatization of Graphitic Carbon Nitride with Methanesulfonyl Chloride: Synthesis, Characterization and Photocatalysis.

Bulk graphitic carbon nitride (CN) was synthetized by heating of melamine at 550 °C, and the exfoliated CN (ExCN) was prepared by heating of CN at 500 °C. Sulfur-doped CN was synthesized by heating of thiourea (S-CN) and by a novel procedure based on the post-synthetic derivatization of CN with methanesulfonyl (CH3SO2−) chloride (Mes-CN and Mes-ExCN). The obtained nanomaterials were investigated by common characterization methods and their photocatalytic activity was tested by means of the decomposition of acetic orange 7 (AO7) under ultraviolet A (UVA) irradiation. The content of sulfur in the modified CN decreased in the sequence of Mes-ExCN > Mes-CN > S-CN. The absorption of light decreased in the opposite manner, but no influence on the band gap energies was observed. The methanesulfonyl (mesyl) groups connected to primary and secondary amine groups were confirmed by high resolution mass spectrometry (HRMS). The photocatalytic activity decreased in the sequence of Mes-ExCN > ExCN > CN ≈ Mes-CN > S-CN. The highest activity of Mes-ExCN and ExCN was explained by the highest amounts of adsorbed Acetic Orange 7 (AO7). In addition, in the case of Mes-ExCN, chloride ions incorporated in the CN lattice enhanced the photocatalytic activity as well.

Degradation of orange II by Fe@Fe2O3 core shell nanomaterials assisted by NaHSO3.

Fe@Fe2O3 core shell nanomaterials with different Fe2O3 shell thickness were synthesized and the Fe@Fe2O3/NaHSO3 Fenton-like system was used for the decomposition of Orange II. The consequences are compared with traditional Fenton Fe@Fe2O3/H2O2 system. The Fe@Fe2O3/NaHSO3 system showed extremely good applicability under both strongly acidic and alkaline conditions. The new Fe@Fe2O3-(2)/NaHSO3 system led to more than 99% degradation in 30s when the pH was 3, which indicated that the Fe@Fe2O3 material was not corroded during the process even under strongly acidic condition. The above Fe@Fe2O3-(2) material was prepared from nano-zero-valent iron aged in solution for 2h to synthesize the Fe2O3 shell. The reaction mechanism of Fe@Fe2O3/NaHSO3 Fenton-like system was also concluded. The oxidation efficiency was highly improved due to rapid electron transfer between Fe core and Fe2O3 shell, which promoted the direct recycling of ≡Fe3+ and ≡Fe2+ and thus accelerated the generation of SO4- and OH radicals.

Degradation of methyl orange by photo assisted fenton reaction using Indonesian bauxite as catalyst

Photo fenton catalyst is an effective and environmentally friendly catalyst for degrade organic pollutants. Novel photo fenton catalyst was successfully prepared from Indonesia bauxite was used as a catalyst for degradation of methyl orange solution. This catalyst is more cheaper than Nafion-based catalyst and more greener than other synthesized catalysts. It is easily prepared from Indonesian natural resources. X-ray diffraction measurements provide structure and mineral composition of bauxite, while XRF provides information on the composition of Fe by 18% by weight of bauxite mass. The presence of large amounts of Fe in bauxite acts as a catalyst in the decomposition of metyl orange. Testing of photo fenton activity to decompose metyl orange showed that Indonesian bauxite had high catalytic activity, was able to decompose 99.4% metyl orange within 40 minutes on irradiation using an 9Watt UVC radiation source.

La2MgTiO6:Eu2+/TiO2-based composite for methyl orange (MO) decomposition

In the recent years, exploring new materials with the photocatalytic functions is a hot research subject, but most of the photocatalysts need an excitation source during the photocatalytic process. In this work, we report the double-perovskite La2MgTiO6:Eu2+ phosphor having the purple-blue afterglow luminescence. Our PL results show that the samples upon excitation at the UV light can show a broad Eu2+ band with the maximum emission intensity at 387 nm. The afterglow range is found to match with the UV absorption region of the TiO2. As a result, we design the UV converted Eu2+ afterglow composite by serving the La2MgTiO6:Eu2+ phosphor as a ceramic substrate to immobilize the TiO2. The photocatalytic experiments reveal the afterglow behavior of La2MgTiO6:Eu2+ phosphor can continuously provide the UV photons to the TiO2 absorption, leading to a continuous-photocatalytic methyl orange degradation in the absence of UV irradiation. Together with the photocatalytic process under the UV irradiation and after removal off the excitation source, a maximum photocatalytic time of 3.5 h is detected.

Cu2O-CuO@biochar composite: Synthesis, characterization and its efficient photocatalytic performance

This research focuses on the facile hydrothermal preparation of Cu2O-CuO@biochar (Cu2O-CuO@BC) composites of different BC content (0.5, 1.0, and 2.0 g/L) as efficient photocatalysts for the decomposition and mineralization of Reactive Orange 29 (RO29). The textural and morphological properties of biochar-based composites were studied utilizing BET, TEM, and SEM analyses. Moreover, EDX, XRD, UV–Vis, DRS and FTIR characterization was carried out to evaluate the elemental composition, crystalline structure, optical characteristics and functional groups of the samples, respectively. The Cu2O-CuO@BC-1.0 composite with a BC content of 1.0 g/L exhibited superior photocatalytic performance than the individual counterparts BC and Cu2O-CuO, due to its narrow band gap and high surface area. These characteristics led to the synergetic ability of UV irradiation and photocatalytic performance of Cu2O-CuO@BC to generate oxidizing species and subsequent radical reactions. The generation of some by-products was verified using GC–MS analysis and accordingly, a possible pathway was proposed. 94.12% degradation efficiency of RO29 was obtained by Cu2O-CuO@BC-1.0 composite at the natural pH of RO29 solution (8.9) and initial RO29 concentration of 20 mg/L after 90 min of photocatalysis. Under identical conditions, 47.31% and 79.62% COD removal efficiencies were observed after 90 and 180 min treatment, respectively.

Facile synthesis of sludge-derived MnOx-N-biochar as an efficient catalyst for peroxymonosulfate activation

Sewage sludge (SS), the inevitable byproduct of wastewater treatment plants, is facing numerous challenges of environmentally safe and cost-effective disposal. Thus, exploration of efficient SS valorization technique is highly desired. In this study, a sludge derived carbon-supported MnOx as a catalyst (ASMn-Nb) was synthesized through NH4OH activation and pyrolysis (800 °C) to enhance peroxymonosulfate (PMS) decomposition and subsequent degradation of acid orange 7 and rhodamine B. The sample characterization indicated that MnCl2 conditioning produces mixed valent Mn oxides on ASMn-Nb, while NH4OH activation significantly enhances N-heteroatoms, surface area, and microporosity. The as-synthesized hybrid catalyst exhibited excellent PMS decomposition ability in a wide range of pH, which enhances AO7 removal efficiency 16%–100% in 40 min compared with that treated with raw sludge biochar. Moreover, the catalyst is recyclable, chemically stable, and produce negligible metal leaching during catalysis. Further investigation of catalytic mechanisms revealed that both radicle and non-radicle processes governing PMS decomposition, whereas mediated electron transfer as the primary and 1O2, SO4−, and OH radicals induced catalysis as the secondary mechanisms of PMS activation and subsequent AO7 degradation. Finally, a probable mechanism of PMS decomposition over ASMn-Nb and AO7 degradation path is proposed. This study concurrently provides a facile route of improving the catalytic performance of sludge derived-biochar and a probable SS valorization technique.

CdIn2S4 surface-decorated Ta3N5 core-shell heterostructure for improved spatial charge transfer: In-situ growth, synergistic effect and efficient dual-functional photocatalytic performance

Efficient design and construction of core-shell heterojunction is regarded as a promising strategy to promote interface electronic transfer for achieving enhanced photocatalytic hydrogen evolution and pollutant degradation. Thus, in this study, a novel core-shell CdIn2S4/Ta3N5 (CIS/TN) nanocomposite photocatalyst was designed and successfully fabricated via the facile in-situ hydrothermal process, where the CdIn2S4 nano-octahedra densely anchored on the surface of Ta3N5 nanoparticles to form the core-shell heterostructure. The as-prepared CIS/TN heterostructures all showed high dual-functional photocatalytic performances for H2 generation and Methyl Orange (MO) decomposition. Compared with pristine CdIn2S4, the photocatalytic activities of CIS/TN heterostructures were obviously enhanced and the sample CIS/TN-3 with the 3 wt% of Ta3N5 possessed the highest H2 production of 122.6 μmol·h−1·g−1, which was about 2.43 times as high as that of CdIn2S4 nano-octahedra. Also, it presented the optimal MO photodegradation efficiency (92.2%) and its rate constant was 2.79 times higher than that of pure CdIn2S4. The wonderful dual-functional photocatalytic performance could be attributed to the broad spectral adsorption region and efficient transfer of photoinduced charge carriers between the intimate heterogeneous interface, which would lead to the higher quantum yield and efficiency. The detailed charge transfer path and possible reaction mechanism were also proposed based on the results of trapping experiments and ESR analysis. Our research may provide a direct guidance for developing other highly-efficient Ta3N5-based core/shell heterostructure for energy conversion and environmental governance.

Novel CdIn2S4 nano-octahedra/TiO2 hollow hybrid heterostructure: In-situ synthesis, synergistic effect and enhanced dual-functional photocatalytic activities

Abstract The development of highly efficient and multifunctional composite photocatalysts for both energy conversion and environmental governance has obtained great concerns. Here, a novel CdIn2S4/TiO2 (CIS/THS) hollow composite photocatalyst was firstly designed and synthesized via a facile in-situ growth process, where the CdIn2S4 nano-octahedra densely attached on the surface of TiO2 hollow spheres to form the unique hybrid heterostructure. The as-synthesized CIS/THS heterojunctions exhibit much superior photocatalytic activities for hydrogen evolution and Methyl Orange (MO) decomposition in comparison to pure CdIn2S4 and TiO2 hollow spheres. The experimental results display that the CIS/THS-3 sample with the 30 wt% of TiO2 presents the optimal photocatalytic H2 production efficiency and its generation rate is 3.38 and 2.56 times as high as those of pure TiO2 and CdIn2S4. Besides, the as-synthesized CIS/THS-3 hybrid also possesses the best MO photodegradation performance and its rate constant is 11.43 and 8.34 times higher than those of pure TiO2 and CdIn2S4. The enhanced photocatalytic activities can be assigned to the synergistic effect, optimized light-harvesting capacity and the formation of hybrid heterostructure for boosting interfacial charge transfer and separation. Furthermore, based on the trapping experiments and ESR analysis, the possible type-Ⅱ interface charge transport mechanism was also proposed. Our study may provide the direct guidance for constructing other hollow TiO2-based composite photocatalysts with superior photocatalytic water splitting and degradation performances.

Hybrid microbial electrolytic/UV system for highly efficient organic pollutants removal

This study for the first time proposed an efficient microbial electrolyte/UV system for Methyl Orange decomposition. With an external applied voltage of 0.2 V and cathode aeration of 20 mL/min, H2O2 could be in-situ generated from two-electron reduction of oxygen in cathode, reaching to 8.1 mg/L in 2 hr and continued to increase. The pollutant removal efficiency of approximate 94.7% was achieved at initial neutral pH, with the activation of •OH in the presence of UV illumination. Although the nature of its guiding principles remain on the vista of practical exploration, this proof-of-concept study provides an alternative operation pattern of solar–microbial hybrid technology for future wastewater treatment from a basic but multidisciplinary view.