Degradation Of Methyl Orange Dye Research Articles

Study of parameters affecting the degradation of rhodamine-B and methyl orange dyes by Annona muricata leaf extract synthesized nanoparticles as well as their recyclability

In this work, a facile and green approach has been employed for the degradation of toxic dyes like rhodamine-B (rh-B) and methyl orange (MO) individually as well as in combination (rh-B+MO) in presence of sodium borohydride (NaBH4). The silver-silver chloride nanoparticles (Ag-AgCl NPs) fabricated using aqueous Annona muricata leaf extract were used as nano-catalysts. Effect of reaction parameters such as nano-catalyst dosage, NaBH4 dosage, temperature and pH were investigated to achieve maximum catalytic efficiency. The maximum degradation was obtained at 100 μg of Ag-AgCl NPs (mass of nano-catalyst), 25 mg of NaBH4 (mass of reducing agent) and 60 °C (temperature). pH 8, 6 and 6 showed maximum degradation for rh-B, MO and rh-B+MO dyes respectively. The experimental data obtained was following the pseudo-first order reaction kinetics. About 96.79 ± 2.61% (0.7485 min−1), 97.51 ± 2.14% (1.0542 min−1) and 97.08 ± 2.63% (0.3474 min−1) degradation was observed for rh-B (under 5 min), MO (under 4 min) and rh-B+MO (under 10 min) dyes respectively. Recyclability studies showed that Ag-AgCl NPs can be recycled and reused up to Cycle 5 (51.11 ± 3.34%) for rh-B, Cycle 6 (47.35 ± 3.19%) for MO and Cycle 3 (45.53 ± 2.32%) for rh-B+MO combination.

Photocatalytic degradation of methyl orange dye by Ti3C2–TiO2 heterojunction under solar light

Photocatalytic activity is a feasible solution to tackle environmental pollution caused by industrial pollutants. In this research, Ti3C2–TiO2 composite with a unique structure was fabricated successfully via a hydrothermal method. Especially, the in-situ transformation of TiO2 from Ti3C2 MXene creates an intimate heterostructure, which leads to prolonging separation and migration of charged carriers. Thus, this Ti3C2–TiO2 composite enhances effectively methyl orange (MO) degradation efficiency (around 99%) after 40 light-exposed minutes. Besides, the optimal concentration of MO solution was estimated at 40 mg/L and Ti3C2–TiO2 photocatalyst also exhibited good stability after five runs. Moreover, the radical trapping test and the MO photodegradation mechanism over Ti3C2–TiO2 system were also demonstrated. This research illustrates the potential of MXenes as effective co-catalysts for photocatalysis and extends the applications of two-dimensional materials.

Characteristics of TiO2 Nanotubes Fabricated by High-Frequency Cyclic Anodization

This study investigates the fabrication of TiO2 nanotubes (TNTs) using the cyclic anodization of Ti foil with high frequency. High-frequency cyclic anodization with increasing duty cycles yields longer, larger, and more regular TNTs, but the walls of the TNTs are thinner. The photocatalytic degradation of methyl orange dye by TNTs indicates that a higher duty cycle during the fabrication of TNTs yields improved performance. For example, the reaction rate constant with a 75% duty cycle (0.0151 ± 0.0003 min−1) is 1.28 times higher than that with a 0% duty cycle (0.0118 ± 0.0018 min−1). It only takes half the time for a 75% duty cycle to reach 70% degradation percentage as compared to, that for the 0% duty cycle. Nevertheless, high-frequency cyclic anodization with increasing duty cycles tends to generate more nanograss on the TNTs and causes a reduction in the TNT strength. Additionally, increasing the duty cycle yields few improvements in the photocurrent and the preferential orientation of anatase TNTs.

Ni-Doped ZnO Thin Films: Deposition, Characterization and Photocatalytic Applications.

Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10-3 and 1.14×10-3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.

In situ growth of 1D/2D CdS–Bi2MoO6 core shell heterostructures for synergistic enhancement of photocatalytic performance under visible light

Stability of the photocatalyst, maximum solar energy harvesting and effective photogenerated charge carrier separation are yet demanding key features of the photocatalysis for pollutant abetment and photo-electrochemical applications. Herein, we report the in situ solvothermal synthesis of CdS–Bi2MoO6 core-shell heterostructures (CdS–Bi2MoO6 CSHs) for the photocatalytic elimination of methyl orange (MO) under visible light. The as-synthesized CdS–Bi2MoO6 CSHs exhibited highest photocatalytic performance of 98.5%, which is approximately 10 and 4 folds higher than pristine Bi2MoO6 nanosheets (NSs) and CdS nanorods (NRs), respectively. This significantly enhanced photocatalytic performance is attributed to the core-shell heterostructure that improves the visible-light harvesting ability, facilitates efficient separation and transfer of the photogenerated charge carriers, as well as synergistic band alignment of both CdS NRs and Bi2MoO6 NSs. The CdS–Bi2MoO6 CSHs also showed efficient photocatalytic performance toward methylene blue (MB) as colored dye and tetracycline hydrochloride (TCH) as a colorless emerging contaminant. Additionally, the outcomes of transient photocurrent, electrochemical impedance, and photoluminescence study further corroborate that the construction of core-shell heterostructures with tight contact, leading to effective charge carrier separation. The hole (h+) and superoxide radical anion (•O2−) were determined to be the predominant active species accountable for the MO dye degradation. Furthermore, the CdS–Bi2MoO6 CSHs exhibited a satisfactory recycling efficiency over five cycles (reduced by approximately 6%), owing to the protective Bi2MoO6 NSs shell over the CdS NRs core, demonstrating their applicability in wastewater purification and photo-electrochemical applications.

Excellent Photocatalytic degradation of Methylene Blue, Rhodamine B and Methyl Orange dyes by Ag-ZnO nanocomposite under natural sunlight irradiation

Highly efficient silver assisted ZnO nanocomposite (AZ) was fabricated by using the co-precipitation method. HR-SEM reveals the presence of nano rods, plates and balls. The incorporation of silver to ZnO reduces the bandgap of ZnO by the Surface Plasmon Resonance effect and this leads to the shift in the emission spectra from ultraviolet (UV) to the visible region. This provide an opportunity to capture large number of photons from the sunlight. The photocatalytic test was conducted under natural sunlight with cationic and anionic dyes. Among all the prepared samples, AZ-1 exhibited the highest photocatalytic degradation efficiency over methylene blue (MB) dye. The prepared samples would create the new pathway for degrading the industrial waste water treatment process.

One-pot green synthesis of Ag@AgCl nanoparticles with excellent photocatalytic performance

Ag@AgCl composites are effective photocatalysts used for degrading organic pollutants, but the limitations of their large-scale production hinder them from having a broad scope of applications. In this study, Ag@AgCl nanoparticles (NPs) with efficient photocatalytic performance were synthesized using a simple and straightforward strategy. Excess chloride (Cl−) ions were added into a silver nitrate (AgNO3)/N,N-dimethylacetamide solution to form [AgCl2]−. The solution of [AgCl2]− was slowly dropped into a 0.5 wt. % polyvinylpyrrolidone solution to obtain silver chloride (AgCl). Neutral silver ions (silver (0) (Ag0)) were produced by the partial decomposition of silver chloride and formed Ag@AgCl under irradiation with visible light. The experimental analysis showed that Ag@AgCl NPs had strong absorption within the range of visible light. They exhibited excellent photocatalytic activity with recyclability for the degradation of methyl orange dyes under visible-light irradiation. The photocatalyst prepared in this study can have practical application in wastewater treatment through the significant degradation of organic pollutants.

Electrochemical and Photocatalytic Properties of Ru-doped TiO2 Nanostructures for Degradation of Methyl Orange Dye

Electrochemical and Photocatalytic Properties of Ru-doped TiO2 Nanostructures for Degradation of Methyl Orange Dye

Green synthesis of iron-based nanoparticles using Chlorophytum comosum leaf extract: methyl orange dye degradation and antimicrobial properties

Nowadays, green synthesis methods have gained growing attention in nanotechnology owning to their versatile features including high efficiency, cost-effectiveness, and eco-friendliness. Here, the aqueous extract of Chlorophytum comosum leaf was applied for the preparation of iron nanoparticles (INPs) to obtain spherical and amorphous INPs with a particle size below 100 nm as confirmed by TEM. The synthesized INPs managed to eliminate methyl orange (MO) from the aqueous solution. The concentration of MO can be easily checked via ultraviolet-visible (UV-Vis) spectroscopy throughout the usage of INPs at the presence of H2O2. The synthesized INPs exhibited MO degradation efficiency of 77% after 6 h. Furthermore, the synthesized INPs exhibited antibacterial activity against both Gram-negative and Gram-positive bacteria. The prepared INPs have an impressive effect on Staphylococcus aureus at concentrations below 6 μg/ml. Overall, the synthesized INPs could considerably contribute to our combat against organic dyes and bacteria.

Synthesis and characterization of CdS/UiO-66/Ag3PO4 nanocomposite for photocatalytic degradation of methyl orange under visible light irradiation

Single, binary and ternary nanomaterials were synthesized by precipitation, solvothermal, simple solution and impregnation methods to serve as photocatalysts. The crystal structure, morphology, band gap energy, functional groups and optical properties of these materials were characterized by XRD, SEM-EDX, UV-Vis, FTIR, and PL instrumental techniques, respectively. Photocatalaytic degradation performances of all the as-synthesized photocatalysts were investigated under visible light irradiation using MO as a model organic pollutant. The photocatalytic degradation performances of all the photocatalysts were evaluated on aqueous solution of the model pollutant dye as well as on a real sewage sample solution collected from Bahir Dar Textile Share Company. Results suggested that the optimized ternary nanocomposite photocatalyst exhibited a relatively higher efficiency towards the photodegradation of both the methyl orange (MO) dye solution (90%) and the real sewage sample solution (71.2%). The effect of operational parameters such as pH (4), initial dye concentration (10 mg/L) and photocatalyst load (0.2 g/L) in MO dye degradation were investigated by using the ternary CdS/UiO-66/Ag3PO4 (R4) nanocomposite.
 
 KEY WORDS: Metal-organic frameworks, Nanocomposite, Ternary system, Photocatalysts, Methyl orange
 
 Bull. Chem. Soc. Ethiop. 2020, 34(3), 571-588.
 DOI: https://dx.doi.org/10.4314/bcse.v34i3.12

Synthesis, characterization and photocatalytic activities of Al-doped ZnO for degradation of methyl orange dye under UV light irradiation

Semiconductor photocatalysts with better photocatalytic properties have been widely researched to be an alternative for dye removal application with better photocatalytic properties. In the present work, Al-doped ZnO which act as a photocatalysts was prepared by modified sol-gel technique at different Al concentrations to evaluate the effect of different Al doping concentration towards the photocatalytic degradation performance of methyl orange dye. The crystallinity of Al-doped ZnO was analysed by X-ray diffraction (XRD) at room temperature. The structural properties, surface morphology and elemental composition were studied via scanning electron microscope (SEM) attached with energy dispersive X-ray spectroscopy (EDS). From XRD, all Al-doped ZnO samples show a polycrystalline nature with a hexagonal wurtzite structure. The average crystallite size was determined by Scherrer’s equation in the range of 79.29–86.50 nm. The Al ion was successfully incorporated into the Zn lattice confirmed by (101) peak shifting from the XRD results. The photocatalytic activities have been carried out by irradiating the photocatalysts under ultraviolet (UV) irradiation. The 1 mol% Al-doped ZnO exhibited a significant increase in the percentage degradation and photocatalytic efficiency compared to others with value of 88.87% degradation and rate constant k of 3.45 × 10−2 min−1 under 60 min irradiation. In the present work, Al-doped ZnO could be reused minimum of five cycles in its recyclability reaction.

Influence of nickel dopant concentration on structural, optical, magnetic and electrochemical properties of TiO2 nanoparticle

In this work, we report enhanced photocatalytic and magnetisation effects of nickel (Ni) ion doped titanium dioxide (TiO2) nano particles. The nano crystalline TiO2 doped with different concentrations of Ni (0.05-0.2%) were prepared by sol-gel method and characterised by various analytical techniques such as X-ray diffraction (XRD), UV-Vis spectroscopy, scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The Ni metal ions incorporation modified the microstructure of TiO2 nano particles considerably which are evident from XRD and SEM analyses. The band gap reduction made by the Ni impurity level extends the TiO2 optical absorption edge to visible region. The photocatalytic activity of TiO2 and Ni-TiO2 was studied by photo degradation of methyl orange dye as a function of irradiation time under visible light. The results signify that TiO2 nanoparticles doped with the higher of concentration of 0.2% Ni improves the reaction rate of hydroxyl radical production. The electrochemical behaviour of the prepared samples was analysed by cyclic voltammetry study. The existence of hard ferromagnetic behaviour with the enhanced magnetisation in Ni doped TiO2 samples make this as an appropriate material for possible applications in spintronic and magneto-electronic devices.

A comparative analysis of photocatalytic activity against methyl orange with C18 derivatives of fatty acid coated Ag/Ag-Ag2O nanoparticles

Even though the photocatalytic methods are better scientific tool for treating hazardous organic contaminants, most of the current photocatalysts are unable to employ sunlight adequately to degrade these pollutants. As reported by various researchers, metal oxide nanoparticles exhibit a substantial photocatlaytic performance under visible radiation source. With this regard, the C18 fatty acids capped Ag/Ag-Ag2O nanoparticles are prepared through a facile and economic friendly chemical method. The structure, crystallinity, size and optical properties of synthesized nanoparticles were characterized by various techniques, like XRD, TEM, XPS; etc. The fine spherical distribution of nanoparticles capped with various fatty acids was confirmed by TEM while crystalline patterns were shown by XRD arrangement. The photocatalytic studies of modified silver nanoparticles have been discussed through the degradation of methyl orange dye under visible light irradiation. The results were in favour with the saturated chain of attached fatty acids with higher degradation percentage compared to the rest of the derivatives. Further the kinetic studies were explained for confirming the outcomes. The photocatalytic observation suggests the fatty acid coated Ag/Ag-Ag2O nanoparticles can be implied as a competent in wastewater treatment.

Studies on the Preparation and Photocatalytic Performance of Bismuth Ferrite

Iron oxide and bismuth oxide powder are synthesized by the liquid phase precipitation method. Then a certain proportion of iron oxide, bismuth oxide and sodium chloride are mixed and ground to prepare the bismuth ferrite precursor by the molten salt method. The bismuth ferrite precursors are calcined at different temperatures to obtain bismuth ferrite photocatalyst. By studying the degradation performance of bismuth oxide, iron oxide and bismuth ferrite photocatalysts for methyl orange dyes, the best conditions for the degradation of methyl orange dyes by bismuth ferrite photocatalysts are found. The experimental results show that the bismuth ferrite prepared by calcining at 750°C has the best degradation. Compared with a single oxide, the photocatalytic performance of bismuth ferrite is better.

Development of activated carbon from parawood using as adsorption sheets of organic dye in the wastewater

Activated carbon derived from parawood was made to be an adsorption sheet by using Triton-x 100 as a binder with the calcination temperature at 600 °C for 1 h. The characteristic properties of all samples were measured through various techniques such as XRD, SEM, BET and UV–vis DRS. The methyl orange (MO) dye was used as a model organic dye for studying photoadsorption ability under UV-light illumination. The experimental results showed that the 5 wt% activated carbon sheet showed a higher adsorption capability of MO dye than that of other samples under the selfsame conditions. Moreover, it showed the excellent stability and recyclability for the degradation of MO dye by five tests. The effect of scavenging species on the photoadsorption mechanism of activated carbon sheet was that superoxide radical and hydroxyl radical scavengers were reckoned to be active species in the photoadsorption process for MO dye degradation under UV-light illumination

Facile Preparation of Self-Assembled Chitosan-Based POSS-CNTs-CS Composite as Highly Efficient Dye Absorbent for Wastewater Treatment.

In this work, a new nanocomposite based on octa-amino polyhedral oligomeric silsesquioxanes (POSS), carbon nanotubes (CNTs), and chitosan (CS) was synthesized and used for wastewater treatment. The properties and morphologies of the prepared composite were analyzed by X-ray diffraction, scanning electron microscopy, transmission electron microscope, thermogravimetric, and atomic force microscopy. The results showed that POSS, CNTs, and CS formed a stable composite through intermolecular forces, and the modification of CS by POSS and CNTs improved its stability. In addition, the obtained composite showed good adsorption performance for the degradation of methyl orange and Congo red dyes. The pseudo-first-order model and pseudo-second-order model were used to analyze the adsorption data, and the results showed that the adsorption process conforms to the kinetic model. Moreover, the maximum adsorption capacity of the composite to methyl orange and Congo red reached 63.23 and 314.97 mg/g, respectively. This work provides new ideas for the preparation of self-assembled multi-composite and their potential applications in wastewater treatment.

Energy and environmental applications of Sn4+/Ti4+ doped α-Fe2O3@Cu2O/CuO photoanode under optimized photoelectrochemical conditions.

The most promising technique for directly converting solar energy into clean fuels and environmental remediation by organic dye degradation is photoelectrochemical (PEC) process. We introduced Sn4+/Ti4+ doped α-Fe2O3@CuxO heterojunction photoanode with complete optimization for PEC hydrogen (H2) generation and organic dye degradation. Improvement of photocurrent photo and reducing overpotentials under optimized conditions lead to enhancing PEC performances, degradation efficiency of organic compounds, and H2 generation generation rate. The optimized heterojunction photoanode (5TiFe@CuxO-D) showed IPCE exceeding 42% compared with pristine hematite (Fe0.01-8006h) nanostructures (28%). Additionally, all the optimized photoanodes showed higher PEC stability for 10h. Time-resolved PL spectra confirm the improved average lifetime for heterojunction photoanodes, supporting the enhanced PEC performance. Optimized 5TiFe@CuxO-D material achieved PEC H2 generation of ∼300μLh-1.cm-2 which is two times higher than pristine hematite's activity (150μLh-1.cm-2) and almost 99% degradation efficiency within 120min of irradiation time. Therefore, a state-of-the-art study has been explored for hematite-based heterojunction photoanodes reflecting the superior PEC performance and hydrogen, methyl orange (MO) dye degradation activities. The improved results were reported because of stable morphology and better crystallinity acquired through systematic investigation of thermal effects and hydrothermal duration, improved electrical properties by Sn/Ti doping into the lattice of α-Fe2O3 and optimization of CuxO deposition methods. The formation of well-defined heterojunction minimizes the recombination of the charge carrier and leads to effective transportation of excited electrons for the enhanced PEC performance.

Synthesis of a Carbon-Loaded Bi₂O₂CO₃/TiO₂ Photocatalyst with Improved Photocatalytic Degradation of Methyl Orange Dye.

A microflower-like C/Bi₂O₂CO₃/TiO₂ nanocomposite was prepared via a two-step method. Scanning electron microscopy (SEM) showed the sample to have a layered petal-like microstructure consisting of many nanosheets with an average diameter of 2-5 μm, along with activated carbon (AC) or carbon nanotubes (CNTs) and TiO₂ nanoparticles deposited on the surface. Compared with pure Bi₂O₂CO₃, Bi₂O₂CO₃/TiO₂ photocatalyst loaded with microflower-like carbon has a good degradation rate of methyl orange (MO) under visible light (0.019 min-1). The highest photodegradation efficiency of MO by AC or CNT-loaded Bi₂O₂CO₃/TiO₂ microflowers reached a maximum of 95% degradation after 180 minutes of reaction. The results show that the photocatalytic reaction of the hole and the hydroxyl free radical groups were important for the process of the photocatalytic degradation, and the effect of the hole was slightly greater than that of the hydroxyl free radical. After comparing the different photocatalysts, it showed that C and TiO₂ could improve the photocatalytic activity of Bi₂O₂CO₃-based photocatalysts.

Visible-light photocatalytic activity and recyclability of N-doped TiO2 films grown by MOCVD

Abstract Nitrogen-doped TiO2 films were grown on borosilicate glass substrates at 400 °C by the metallorganic chemical vapor deposition (MOCVD) for removing dye from water under visible light. The effect of N-doping on the structural, surface, and photocatalytic properties of films was evaluated. X-ray photoelectron spectroscopy (XPS) analyses revealed that 1.56 and 2.44 at% of nitrogen were incorporated into the films by varying the NH3 flux during the growth. Methyl orange dye degradation experiments showed that the N-doped films presented photoactivity under visible light. The film containing 2.44 at% of nitrogen exhibited the best photocatalytic behavior, with 55% of efficiency. Recyclability tests under visible light showed that the film efficiency dropped gradually after each test. N-TiO2 films grown by MOCVD have the potential to be used in environmental applications by removing pollutants using a green method under sunlight or even under internal illumination, although its reuse is limited.

Tantalum Oxide Nanoparticles Prepared from Imidazolium Ionic Liquids as Active Hybrid Materials for Enhanced Photocatalytic Degradation of Dyes

AbstractTantalum oxide nanoparticles prepared from the hydrolysis of 1‐alkyl‐3‐methylimidazolium hexachlorotantalate ionic liquids showed an unprecedented efficiency for the photocatalytic degradation of methylene blue and methyl orange dyes in aqueous solutions. Indeed, the photodegradation of these aqueous dyes (up to 94 %) promoted by the Ta2O5 nanoparticles occurred in shorter reaction times when compared to commercially available Ta2O5 under the same reaction conditions. Moreover, the presence of residual ionic liquid and the pH of the medium seem to play significant roles in the photodegradation process. In particular, a significant synergistic effect occurred when the remaining ionic liquid and HCl are present at the surface of the hybrid nanoparticles. This effect provided favorable hydrophilic regions and pH conditions for the photodegradation of the dyes.