Methyl Orange Aqueous Solution Research Articles

Preparation of Composites Derived from Modified Loess/Chitosan and Its Adsorption Performance for Methyl Orange.

A modified loess/chitosan composite (ML@CS) was prepared via solution. The microstructure and physicochemical properties of ML@CS were characterised via scanning electron microscope (SEM), Zeta potential, X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), and thermogravimetric analysis (TGA). An aqueous solution of methyl orange (MO) was used as simulated wastewater from which the influence of the initial concentration and pH of MO, the dosage amount and regeneration performance of ML@CS, adsorption temperature, and time on the adsorption effect of MO were systematically investigated. The adsorption kinetics, isothermal adsorption, and adsorption mechanism were also analysed. The results indicate that ML@CS had a good adsorption effect on MO. When the initial concentration of MO was 200 mg/L, pH was 5.0, and ML@CS dosage was 1.0 g/L, the adsorption equilibrium could be reached within 180 min at room temperature, and the equilibrium adsorption capacity and removal rate reached 199.52 mg/g and 99.75%, respectively. After five adsorption-desorption cycles, the MO removal rate remained above 82%. The adsorption behaviour of ML@CS for MO conforms to the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model. The spontaneous exothermic process was mainly controlled by monolayer chemical adsorption and the physical adsorption only played an auxiliary role. ML@CS efficiently adsorbed MO in water and can be used as a high-efficiency, low-cost adsorbent for printing and dyeing wastewater treatment.

Reversible Color Loss in Aqueous Methyl Orange Solutions Induced by Freezing

Reversible Color Loss in Aqueous Methyl Orange Solutions Induced by Freezing

Fabrication of cobalt oxide nanosheets using Withania somnifera root extract for degradation of organic pollutants

In today’s scenario, material science emerges as pivotal players, as it is an emerging and fast-growing interdisciplinary field. Nanomaterials are increasingly popular among researchers due to their unique physicochemical properties and multifaceted applications. Recently, researchers are exploring more sustainable approaches for the synthesis of nanomaterials due to its numerous advantages. In this context, present investigation reports an approach for the synthesis of cobalt oxide nanosheets (Co3O4 NSs). This approach leverages environmentally friendly and sustainable methods, minimizing the use of hazardous chemicals and reducing energy consumption. Hence it involved Withania somnifera (ashwagandha) root extract as a greener reductant as well as stabilizing agent. The synthesized Co3O4 NSs were thoroughly analyzed using various techniques, including ultraviolet-visible (UV–vis) spectroscopy, fourier-transform infrared spectroscopy (FTIR), powder x-ray diffraction (PXRD), and field emission scanning electron microscopy (FE-SEM). A sharp absorption peak at 252 nm with a tail towards higher wavelength reveal the formation of Co3O4 NSs. The diffraction pattern reveals a face centered cubic structure of Co3O4 NSs. Morphological studies confirmed the substantial surface area of Co3O4 NSs which enable us to perform the catalytic degradation of azo dye, i.e., methyl orange. It provides that 10 mg of Co3O4 NSs is sufficient to degrade a 10 ppm aqueous methyl orange solution by 75.82 % in the dark and by 96.12 % under sunlight exposure. Thus, this study offers an excellent pathway for the synthesis of Co3O4 NSs and demonstrates their potential as a promising material for future catalytic applications.

Functionalized lignin magnetic composites and their absorption capability for methylene blue and methyl orange in aqueous solution

Functionalized lignin magnetic composites and their absorption capability for methylene blue and methyl orange in aqueous solution

Facile in-situ fabrication of graphene oxide/poly(ionic liquid) composites and their adsorption performance for methyl orange

This work reveals a facile in-situ fabricating strategy for graphene oxide/poly(ionic liquid) composites toward the effective adsorption of methyl orange in aqueous solution. This synthetic route includes the formation of novel surfactant-free ionic liquid microemulsions and the stable solubilization of graphene oxide. To characterize the designed composites, FTIR, XRD, TGA, SEM, DSC, and XPS analyses were conducted, and the adsorption isotherms/kinetics of the designed composites toward methyl orange were further investigated. Results indicated that graphene oxide/poly(ionic liquid) composites can be in-situ synthesized facilely within the surfactant-free ionic liquid microemulsions, and the network structure of composites can be adjusted effectively by altering the dosage of co-solvent. In addition, the graphene oxide/poly(ionic liquid) composites prepared in situ exhibited a remarkable adsorption performance of methyl orange. These findings indicate the great application potential of graphene oxide/poly(ionic liquid) composites in the field of cationic dye adsorption.

A novel graphene-N/TiO2-nickel foam: Preparation and application in photoelectric synergistic degradation of methyl orange

Photoelectric synergistic degradation of dye wastewater has been developed. In this experiment, we prepared Nitrogen-doped titanium dioxide-graphene/nickel foam (N/TiO2-Gr/F–Ni) by electrophoresis and impregnation methods, to degrade methyl orange (MO) aqueous solution. Firstly, nitrogen-doped titanium dioxide particle (N/TiO2) was prepared by the sol-gel method, which showed a photocatalytic degradation catalytic kinetic constant of 1.8 × 10−2 min−1 under simulated sunlight. Meanwhile, graphene (Gr) was loaded on nickel foam (F–Ni) to prepare Gr/F–Ni electrode by electrophoresis method, which obtained a catalytic kinetic constant of 1.15 × 10−2 min−1 at 10 V. Finally, N/TiO2 was loaded on Gr/F–Ni to prepare N/TiO2-Gr/F–Ni photoelectrode by electrophoresis and impregnation methods, which had a catalytic kinetic constant of 3.96 × 10−2 min−1 at 10 V and under 1 sun. The results show that there is a synergistic effect between light degradation and electro-Fenton oxidation because the bonding electrons in N/TiO2 are activated to produce photogenerated electron-hole pairs. On the other hand, the separation efficiency of the photogenerated electron is enhanced by the Gr.

Enhanced Photocatalytic Performance of Cr/Ni/Mg/Al Layered Double Hydroxides against Methyl Orange in Aqueous Solution

Layered double hydroxides (LDHs) have received substantial research as manufacturing innovation and prospective photocatalysts for the degradation of organic contaminants due to large surface area, strong anionic exchange capacity, and tunable composition. In this study, we modified Mg/Al-LDHs with Ni and Cr to further enhance their performance in removing Methyl Orange (MO) an anionic dye widely used in textiles, cosmetics, and healthcare products. The modified Mg/Al-LDHs were synthesized using hydrothermal co-precipitation method and characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD). The breakdown rate of MO under solar light was used for evaluating the material's photocatalytic activity. The outcomes demonstrated that the Ni/Mg/Al/Cr (LDH-4) photocatalysts degraded MO more quickly than the undoped substance. The addition of Cr to the Ni/Mg/Al matrix caused the band gap to develop new energy levels, which increased the material's photocatalytic activity. The Ni/Mg/Al doped with Cr has demonstrated tremendous potential as a photocatalysts for the MO degradation.

Photocatalytic bioheteronanostructures by integrating multicomponent Cu2O–Au nanoparticles into ZnO-coated butterfly wings colored by photonic nanoarchitectures

Complex biological photocatalytic heteronanostructures were produced by the integration of different multicomponent Au–Cu2O nanoparticles (NPs) into the blue-colored photonic nanoarchitectures occurring in the wings of male Polyommatus icarus butterflies. Both bare wings and wings conformally coated by 15-nm ZnO by atomic layer deposition were used as substrates. The NPs were characterized by UV–visible spectroscopy, focus stacking optical microscopy, and electron microscopy. After the deposition of the different NPs, the photocatalytic performance of the samples under visible light illumination was tested by the photodegradation of methyl orange in aqueous solution monitored continuously by an immersion probe. It was found that the components of the biological hetero-nanoarchitecture: ZnO-coated wings and wings without ZnO with deposited NPs exhibited poor catalytic performance. But the combined system: ZnO-coated wings with NPs deposited onto them exhibited sixfold to eightfold increase in their catalytic performance. This increase is attributed to the extension of the ZnO absorption into the visible range and to the formation of the heterojunction between the n-type ZnO and the p-type Cu2O NPs which resulted in the charge transfer of the photogenerated carriers. As the samples exhibited good stability under the continuous magnetic stirring, they can be used in flow-through systems suitable for wastewater remediation. The biological templates for the hetero-nanoarchitectures were produced by the controlled breeding of herbivorous insects, which does not raise any environmental concerns.

Preparation of anion‐uptake powder compact containing layered double oxide and metakaolinite

AbstractA powder compact with anion‐uptake ability was prepared prior to the proceeding of the solid‐state reaction involving layered double hydroxide (LDH) and kaolinite during calcination. LDH features anion‐exchangeable capability, and kaolinite is used as a raw potty material because of the sintering property. In the present study, the solid‐state reaction of LDH with kaolinite did not proceed at 750°C, resulting in the formation of a mixture of layered double oxide (LDO) and metakaolinite. Unlike LDO, which typically undergoes anion‐uptake accompanied by LDH reconstruction, metakaolinite does not revert to kaolinite without the use of hydrothermal conditions. In addition, the powder compact composed of LDO crumbled, whereas the one containing a mixture of LDO and metakaolinite remained intact. When the powder compact of LDO and metakaolinite mixture was immersed in a methyl orange (MO) aqueous solution, an LDH–MO intercalation compound was generated within the compact. By contrast, no such compound was generated when LDO powder was immersed in an MO aqueous solution. These results indicated that the successful preparation of a powder compact with distinct anion‐uptake ability was different from powder, owing to that the solid‐state reaction of LDO with metakaolinite did not proceed at 750°C.

Evaluation of the Adsorptive Performance of Rambutan-shaped γ-Al2O3 Micro-nanostructure against Wastewater Containing the Azo Dye: Methyl Orange

Aim: The aim of this study is to explore and evaluate the possibility of rambutan-shaped micro-nanostructured γ-Al2O3 material’s usage as an adsorbent in industrial wastewater processing. Background: Every year, more than 7 million tons of dyestuff-containing wastewater are produced in the industry. Although there are many adsorbents like fly ash and clays, the shortages limit their actual applications. It is still necessary to find a new cheaper adsorbent. Objective: The paper aimed to investigate the adsorption capacity and decolorization ability of rambutan- shaped γ-Al2O3 material synthesized via a composite soft template method. Methods: The rambutan-shaped γ-Al2O3 material was prepared and characterized via XRD, TEM, FE-SEM, and FT-IR (See our group’s published article in “Ming Shen*, et al., Acta Phys.-Chim. Sin. 2013, 29 (10), 2286-2294”). The methyl orange aqueous solution was selected as the model of industrial wastewater. The methyl orange solution (15.0 mg·L-1) with different pH (2~9) was exposed to a series of amounts of γ-Al2O3 powder ranging from 10.0 to 70.0 mg. Different concentrations of methyl orange solution, ranging from 5.0 to 200.0 mg·L-1 were also tested with the same amount of γ-Al2O3 powder (50.0 mg). The adsorption-calcination cycle analysis was performed with methyl orange solution (50.0 mg·L-1) and 500.0 mg of γ-Al2O3 powder at pH=3. Results: The γ-Al2O3 material exhibits excellent adsorption capacity (114.10 mg·g-1) towards acidic methyl orange aqueous solution. At the same time, the decolorization rate of the γ-Al2O3 material reaches about 88%. This material still keeps a 50% decolorization rate after 6 repeats of the adsorption- calcination cycle. Moreover, the excellent self-sedimentation ability of this material also provides an easy separation for future industrial applications. Conclusion: The γ-Al2O3 material with rambutan-like micro-nanostructure presents excellent adsorption capacity/decolorization ability and self-sedimentation ability. It can be used as a new type of adsorbent for wastewater processing. The rambutan-shaped micro-nanostructure plays an important role in maintaining the adsorption ability of the γ-Al2O3 material.

High-entropy selenide catalyst for degradation of organic pollutants

In this study, pollution from sewage was addressed using a novel high-entropy material to decompose organic pollutants containing azo groups. Se_(AlCrCuFeNi) (Se_HEC) nanomaterials were employed as an active catalyst to restore organic pollution in aqueous solutions by using the electro-Fenton technique. The efficacy of Se_HEC catalysts in degrading pollutants during the electro-Fenton reaction and the potential of functionalized high-entropy materials to decompose pollutants were investigated. The Se_HEC material was synthesized through rapid calcination followed by selenization. This Se_HEC cathode demonstrated a remarkable removal efficiency of 98% for methyl orange in aqueous solutions and high stability in an acidic environment with a pH of 3. Additionally, the effects of various parameters, such as applied current and pH, were assessed. The results revealed that an increase in the current led to a higher reaction rate for the entire process, with the optimal conditions occurring at pH 3. The potential methyl orange degradation pathway was elucidated through a reactive oxygen species (ROS) test conducted during the electro-Fenton process.

Magnetic chitosan-functionalized waste carton biochar composites for efficient adsorption of anionic and cationic dyes

In this study, BC-CoFe2O4-CS magnetic composite was successfully prepared from waste cardboard and investigated as an efficient adsorbent for the removal of amaranth and methyl orange in aqueous solution. First, the fibers obtained from the cardboard waste were carbonized by a hydrothermal process to produce biochar. Subsequently, the final magnetic composites were synthesized by in situ growth and Schiff base crosslinking reactions. The composites were characterized by zeta potential, Brunauer–Emmett–Teller measurements, Fourier transform Infrared spectroscopy, Scanning electron microscopy, Energy dispersive spectrometer,X-ray Diffraction, Thermogravimetry analysis and Vibrating sample magnetometer. The effects of adsorbent dosage and initial solution pH on dye removal efficiency were studied. The results showed that the maximum adsorption capacity of amaranth could reach 500.6 mg·g−1 at pH = 2, the adsorbent dosage of 0.5 mg·ml−1, and methyl orange could reach 644.0 mg·g−1 at pH = 4, the adsorbent dosage of 0.5 mg·ml−1. The adsorption process followed the pseudo-second order kinetic models and Langmuir isotherm. BC-CoFe2O4-CS was easily separated from the aqueous solution due to the loading of CoFe2O4 magnetic nanoparticles. Besides, the BC-CoFe2O4-CS could be further used after the adsorption experiments with or without desorption and still showed good adsorption performance in the actual water samples. Therefore, it is expected that the composite material prepared from waste cartons can be used for the treatment of dye-containing wastewater due to its low cost, high efficiency, and simple application.

Chemical waste treatment based on hydrogen energy (II): Aqueous methyl orange solution under the oxyhydrogen flame

The oxyhydrogen flame (OHF) can generate temperatures as high as 2800 K and a jet flow of highly reactive free radicals including H, OH, HO2 and O. Therefore, it could serve as an effective means for treating various chemical wastes, particularly organic wastes. Building upon our previous research on metal chlorides, we present here a study on the degradation mechanism of aqueous methyl orange (MO) solution under OHF. Although the decolorization of MO solution is rapid, complete degradation is a slow and intricate process. Initially, MO solution undergoes decolorization by breaking the azo bond followed by oxidation processes that convert aminobenzene compounds to benzoquinone and break down the benzene ring until ultimately being fully converted into CO2 and H2O.

A bifunctional imidazolium-based porous organic polymer for efficient detection of Cr2O72− and adsorptive separation of Cr2O72− and MO in water

The presence of heavy metal ions and organic dyes in aqueous solutions has a significant impact on the ecological environment and human health. Herein, a novel bifunctional imidazolium-based porous organic polymer (IMSPF-Br-C=C) was prepared successfully via quaternization reaction of spirobifluorene and 1,4-dibromo-2-butene. The synthesized material was characterized by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), Fourier transform infra-red spectra (FTIR), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), N2 adsorption-desorption analysis and solid-state 13C CP/MAS NMR spectroscopy, confirming its structure and stability. Owing to the conjugated structure of spirobifluorene, IMSPF-Br-C=C showed excellent recognition performance for dichromate anion (Cr2O72−) with the limit of detection (LOD) of 1.58 μmol/L. In addition, IMSPF-Br-C=C with the abundant imidazolium cations showed the outstanding adsorption performance in the removal of Cr2O72− and methyl orange (MO). Removal efficiencies and adsorption capacities of IMSPF-Br-C=C were 98.3 % and 99.4 %, 452.8 and 1304.2 mg/g in 6 min, respectively. The results show that the electrostatic interactions and π-π stacking play crucial roles in the fluorescence detection of Cr2O72− and adsorptive separation of Cr2O72− and MO. Furthermore, physico-chemical techniques, density functional theory (DFT) calculation and frontier molecular orbital theory (FMO) were used to explain action mechanism. This work provides a cost-effective IMSPF-Br-C=C as a bifunctional platform for sensing Cr2O72− and adsorptive separation of Cr2O72− and MO in aqueous solution.

Characterization of an Iron-Copper Bimetallic Metal-Organic Framework for Adsorption of Methyl Orange in Aqueous Solution.

Iron-based organic frame material MIL-53 (Fe) was synthesized by the hydrothermal method with Cu2+ incorporated to obtain bimetallic composite MIL-53 (Fe, Cu). The structure and morphology of the material were characterized by SEM, XRD, BET, FTIR, XPS, and zeta potential. The adsorption performance of MIL-53 (Fe, Cu) on methyl orange was tested under a variety of conditions, including the effects of pH and material dosage, by the static adsorption test. The results show that under the condition of pH = 7, a temperature of 30°C, and an adsorbent dosage of 20 mg, the removal rate of MIL-53 (Fe, Cu) for methyl orange can reach more than 96% within 4 h, and the maximum adsorption capacity after fitting by the thermodynamic model can reach 294.43 mg/g, showing the excellent adsorption performance of MIL-53 (Fe, Cu) on methyl orange. In addition, by exploring the adsorption mechanism of MIL-53 (Fe, Cu) on methyl orange, it is found that the adsorption of MIL-53 (Fe, Cu) on methyl orange depends on chemical adsorption, as evidenced by combining Fe3+ and Cu2+ in the material with methyl orange molecules to form complexes to achieve adsorption. While the specific surface area of the material had no obvious effect on adsorption, the effects of pH, temperature, and concentration were explored. At a pH of 6.5, greater adsorption occurred at higher temperatures, as determined by thermodynamic model fitting, as well as with higher initial methyl orange molecule concentration.

Removal of Methyl Orange in Aqueous Solutions Using Hydrochloric Acid-Modified Kaolinite Supported Nanosized Zero-Valent Iron

Removal of Methyl Orange in Aqueous Solutions Using Hydrochloric Acid-Modified Kaolinite Supported Nanosized Zero-Valent Iron

Synthesis, Crystal Structure, and Photocatalytic Properties of Two Isoreticular Ce(IV)-MOFs with an Infinite Rod-Shaped Inorganic Building Unit.

The use of the V-shaped linker molecules 4,4'-oxydibenzoic acid (H2ODB) and 4,4'-carbonyldibenzoic acid (H2CDB) led to the discovery of two isoreticular Ce(IV)-based metal-organic frameworks (MOFs) of composition [CeO(H2O)(L)], L = ODB2-, CDB2-, denoted CAU-58 (CAU = Christian-Albrechts-University). The recently developed Ce-MOF synthesis approach in acetonitrile as the solvent proved effective in accessing Ce(IV)-MOF structures with infinite rod-shaped inorganic building units (IBUs) and circumventing the formation of the predominantly observed hexanuclear [Ce6O8] cluster. For the structure determination of the isoreticular MOFs, three-dimensional electron diffraction (3D ED) and powder X-ray diffraction (PXRD) data were used in combination with density functional theory (DFT) calculations. [CeO(H2O)(CDB)] shows reversible H2O adsorption by stirring in water and thermal treatment at 190 °C, which leads to a unit cell volume change of 11%. The MOFs feature high thermal stabilities (T > 290 °C), which exceed those of most Ce(IV)-MOFs and can be attributed to the infinite rod-shaped IBU. Surface and bulk oxidation states of the cerium ions were analyzed via X-ray photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES). While Ce(III) ions are observed by the highly surface-sensitive XPS method, the bulk material contains predominantly Ce(IV) ions according to XANES. Application of the MOFs as catalysts for the catalytic degradation of methyl orange in aqueous solutions was also studied. While degradation activity for both MOFs was observed, only CAU-58-ODB revealed enhanced photocatalytic activity under ultraviolet (UV) light. The photocatalytic mechanism likely involves a ligand-to-metal charge transfer (LMCT) from the linkers to the Ce(IV) centers. Analyses by XANES and inductively coupled plasma-optical emission spectroscopy (ICP-OES) demonstrate that leaching of Cerium ions as well as partial reduction of Ce(IV) to Ce(III) takes place during catalysis. At the same time, PXRD data confirm the structural stability of the remaining MOF catalysts.

Adsorption of methyl orange dye by SiO2 mesoporous nanoparticles: adsorption kinetics and eco-toxicity assessment in Zea mays sprout and Artemia salina.

Herein, we prepared the silica nanoparticles (SiO2 NPs) by a modified Stober's method for methyl orange (MO) removal. The SiO2 NPs were found to be spherical with a zeta size of 152.5 d. nm, a PDI of 0.377, and a zeta potential of -5.59 mV. The effect of different parameters (initial dye concentration, reaction time, temperature, and pH) on the adsorption of MO by SiO2 NPs was determined. The adsorption pattern of SiO2 NPs was highly fitted with the Langmuir, Freundlich, Redlich-Peteroen, and Temkin isotherm models. The highest adsorption rate was recorded at 69.40 mg/g of SiO2 NPs. Furthermore, the toxic effect of before and after removal of MO in aqueoussolution was tested in terms of phytotoxicity and acute toxicity. The SiO2 NPs treated MO dye solution were not exhibited significant toxicity to corn seeds and Artemia salina. These results indicated that SiO2 NPs can be used for the adsorption of MO.

Synthesis of TiO<sub>2</sub>/Gd<sub>2</sub>O<sub>3</sub> and TiO<sub>2</sub>/Gd<sub>2</sub>O<sub>3</sub>/Ag Nanomaterials. Application in Photocatalytic Degradation Reactions

A technique for the template synthesis of nanocrystalline titanium(IV) oxide and its modification with nanoparticles of gadolinium(III) oxide and silver has been developed. The composition and structure of the obtained materials were characterized by X-ray phase analysis and IR spectroscopy. The specific surface area and pore size distribution were determined. The photocatalytic properties of the synthesized TiO2/Gd2O3 and TiO2/Gd2O3/Ag nanomaterials were evaluated in the reaction of degradation of aqueous solutions of methyl orange upon irradiation with UV light. It was found that the introduction of gadolinium (III) oxide increases the photocatalytic activity, and the introduction of silver particles makes the photocatalyst sensitive to light with a shorter wavelength.

Defective multi-element hydroxides nanosheets for rapid removal of anionic organic dyes from water and oxygen evolution reaction

Water pollution by dyes is one of the biggest environmental problems. Adsorption technology has been widely used in wastewater treatment. In this work, high-entropy concept is used to design surface defective hydroxides realizing the rapid removal of dyes from water. Multi-element hydroxides (MEHs) containing three (CoMnNi, MEH-Ternary), four (CoMnNiZn, MEH-Quaternary), and five (CoMnNiZnFe, MEH-Quinary) metal elements are successfully synthesized through a polyol process. These as-synthesized MEHs are composed of nanosheets with a brucite-like structure. Along with the increase in compositional complexity (i.e., configurational entropy), the thickness of the nanosheets in these MEHs decreases, while the degree of surface defects increase. These surface defects are probably the active sites for anionic dyes adsorption, suggesting rapid adsorption kinetics with shortened diffusion path length. For MEH-Quinary in 0.2 mM Congo red (CR) and MEH-Ternary in 0.4 mM methyl orange (MO) aqueous solutions, respectively, high removal efficiency > 99.0% is achieved in the first 30 s. Their pseudo-second-order rate constants are two orders of magnitude higher than that of activated carbon and hydrotalcite. MEH-Quinary has maximum CR and MO adsorption quantity of 546.4 and 404.9 mg g-1, respectively, by Langmuir model. The MEH-Quinary is also a potential electrocatalyst for oxygen evolution reaction.