Photocatalytic Degradation Of Methyl Orange Research Articles

Synthesis of Chitosan-Agar immobilized NiO-MgO bionanocomposites and their photocatalytic application towards toxic azo dye

In this study, NiO-MgO nanoparticles (NiMg NPs) were synthesized and incorporated into a biopolymer blend of chitosan (CTS) and agar agar gum (AA), forming the novel CTAG@NiMg bionanocomposite (BNC). Structural analysis revealed a crystal size of 19 nm and a direct band gap of 2.75 eV, indicating strong potential as a UV-active photocatalyst. TEM images confirmed uniform nanoparticle distribution with an average size of 25 nm. The elemental composition, verified by EDX spectra, showed weight percentages of C (21.32 %), O (31.47 %), Ni (35.39 %), and Mg (11.82 %). The CTAG@NiMg BNC demonstrated outstanding photocatalytic degradation of methyl orange (MO) dye, achieving 99.52 % degradation at pH 4 with 20-ppm concentration after 60 min under UV irradiation. The degradation followed pseudo-first-order kinetics, with rate constants (k1) ranging from 0.011 to 0.030 min−1, and a minimum half-life of 25.8 min at 15 ppm. Hydroxyl radicals (•OH) were identified as the primary reactive species driving the photocatalytic process. The material exhibited excellent reusability, retaining high degradation efficiency over four cycles. Compared to similar photocatalysts, CTAG@NiMg BNC demonstrated superior performance, faster degradation rates, and greater stability. Its enhanced surface area and porosity, as confirmed by BET analysis, contributed to better dye adsorption and faster reaction times. These properties make the CTAG@NiMg BNC a highly efficient, sustainable, and recyclable photocatalyst for environmental remediation, particularly in treating organic pollutants like methyl orange from aqueous solutions.

ZnO/Zn3(PO4)2/CeO2 photocatalysts formed on zinc by plasma electrolytic oxidation

ZnO/Zn3(PO4)2 coatings doped with CeO2 particles for use in photocatalytic degradation of methyl orange (MO) were created by plasma electrolytic oxidation of zinc in a phosphate alkaline electrolyte (PAE) with CeO2 particle concentrations of up to 1.5 g/L. The CeO2 particle content in ZnO/Zn3(PO4)2 coatings was determined by the concentration of CeO2 particles in the PAE. Extensive research was conducted on coating morphology, chemical and phase compositions, and light-harvesting properties. The photocatalytic activity (PA) of ZnO/Zn3(PO4)2/CeO2 coatings was higher than ZnO/Zn3(PO4)2. The PA of ZnO/Zn3(PO4)2/CeO2 coatings strongly depends on the amount of CeO2 particles in PAE, and the highest PA was observed for ZnO/Zn3(PO4)2/CeO2 coating formed in PAE by adding 0.75 g/L of CeO2 particles. The higher PA of ZnO/Zn3(PO4)2/CeO2 compared to ZnO/Zn3(PO4)2 is due to a lower photogenerated electron/hole recombination. The photocatalytic degradation of MO followed a pseudo-first order kinetic model and the reaction constant of the most photoactive ZnO/Zn3(PO4)2/CeO2 coating was increased about twofold compared to the ZnO/Zn3(PO4)2 coating. After 6 h of irradiation, the PA for ZnO/Zn3(PO4)2 and the most photocatalytically active ZnO/Zn3(PO4)2/CeO2 was about 70 % and 98 %, respectively. A mechanism for the photodegradation of MO with the ZnO/Zn3(PO4)2/CeO2 photocatalyst was also proposed.

Ultrahigh-Strength Textile Fiber-Supported Schiff Base Copper Complexes for Photocatalytic Degradation of Methyl Orange

Ultrahigh-Strength Textile Fiber-Supported Schiff Base Copper Complexes for Photocatalytic Degradation of Methyl Orange

Synergistic Effect of NiAl-Layered Double Hydroxide and Cu-MOF for the Enhanced Photocatalytic Degradation of Methyl Orange and Antibacterial Properties

This study synthesized NiAl-layered double hydroxide (LDH)/Cu-MOF photocatalyst using a simple impregnation method involving NiAl-LDH and Cu-MOF. The successful synthesis was confirmed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential measurements, thermogravimetric analysis (TGA), ultraviolet diffuse reflectance spectroscopy (UV-DRS), N2 adsorption at −196 °C, and electrochemical impedance spectroscopy (EIS). Photocatalysts based on NiAl-LDH, Cu-MOF, and NiAl-LDH/Cu-MOF were used to remove methyl orange (MO) dye from contaminated water. The impact of various factors, including pH, dye concentration, and photocatalyst amount, on MO degradation efficiency was assessed. FTIR analysis was conducted both before and after dye degradation. The optimal degradation conditions were a photocatalyst dose of 25 mg and a pH of 3. Kinetic studies indicated that the degradation of MO dye onto NiAl-LDH/Cu-MOF followed a pseudo-first-order and an L–H or Langmuir–Hinshelwood model. The value of R2 = 0.94 confirms the validity of pseudo-first-order and Langmuir–Hinshelwood (L–H) kinetic models for the photocatalytic degradation of MO dye. This study highlights the importance of developing novel photocatalysts with improved degradation efficiency to protect the water environment. Antibacterial activity was also performed with antibacterial sensibility testing by disk diffusion to determine minimal inhibitory and bactericidal concentrations. In short, NiAl-LDH/Cu-MOF can be helpful for various biomedical and industrial applications.

Photocatalytic Degradation of Methyl Orange Using Iron Oxide Nanoparticles Using Lotus Seeds

Photocatalytic Degradation of Methyl Orange Using Iron Oxide Nanoparticles Using Lotus Seeds

Investigation of MO Adsorption Kinetics and Photocatalytic Degradation Utilizing Hollow Fibers of Cu-CuO/TiO2 Nanocomposite.

This comprehensive study explores the kinetics of adsorption and its photocatalytic degradation of methyl orange (MO) using an advanced copper-decorated photocatalyst in the form of hollow fibers (HFs). Designed to boost both adsorption capacity and photocatalytic activity, the photocatalyst was tested in batch experiments to efficiently remove MO from aqueous solutions. Various isotherm models, including Langmuir, Freundlich, Sips, Temkin, and Dubinin-Radushkevich, along with kinetic models like pseudo-first and pseudo-second order, Elovich, Bangham, and Weber-Morris, were utilized to assess adsorption capacity and kinetics at varying initial concentrations. The results indicated a favorable MO physisorption on the nanocomposite photocatalyst under specific conditions. Further analysis of photocatalytic degradation under UV exposure revealed that the material maintained high degradation efficiency and stability across different MO concentrations. Through the facilitation of reactive oxygen species generation, oxygen played a crucial role in enhancing photocatalytic performance, while the degradation process following the Langmuir-Hinshelwood model. The study also confirmed the robustness and sustained activity of the nanocomposite photocatalyst, which could be regenerated and reused over five successive cycles, maintaining 92% of their initial performance at concentrations up to 15 mg/L. Overall, this effective nanocomposite photocatalyst structured in the form of HF shows great promise for effectively removing organic pollutants through combined adsorption and photocatalysis, offering valuable potential in wastewater treatment and environmental remediation.

Influence of TiO2 Phases and Operational Parameters on Photocatalytic Degradation of Methyl Orange

Influence of TiO2 Phases and Operational Parameters on Photocatalytic Degradation of Methyl Orange

Exploring the Enhancement of Photocatalytic Performance in TiO2 based Hollow Composites: Size Effect of the Adsorbed CeO2 Particles

AbstractThe photocatalytic (PC) behavior of CeO2–TiO2 hollow composites with different heterojunction structures are investigated. The composites are fabricated by combining TiO2 hollow spheres and CeO2 nanoparticles with changing the ratio between Ce and Ti. High‐resolution microscopic and spectroscopic analysis demonstrates that three types of cerium‐bearing structures form on the surface of the titania. The first involves Ce atoms adsorbed onto the surface of TiO2 particles. The second occurs with small CeO2 particles, ≈2 nm in size, resulting from the aggregation of the adsorbed Ce atoms, thus forming a CeO2–TiO2 heterojunction. The last type is obtained through the growth of the CeO2 particles up to 10 nm in size. All the CeO2–TiO2 composites exhibit enhanced photocatalytic degradation of methyl orange under visible light irradiation compared to mere CeO2 or TiO2 nanoparticles. The synergistic effect of these three structures leads to a competition between size effects and interface interactions, which affects the band alignment, the number of defects, and, consequently, the PC activity. The highest PC reaction rate constant under visible light reaches up to 0.017 min−1 and is achieved when the CeO2 nanoparticle size is smaller than its Debye length.

Controllable preparation of red phosphorus nanoribbons for enhanced photocatalytic degradation of Methyl Orange and Tetracycline.

Nanoribbons (NRs), leveraging the flexibility of one-dimensional materials and the expansive surface area of two-dimensional materials, offer heightened exposure to edge sites and superior charge transfer rates. Consequently, they present promising prospects within the domain of photocatalysis. Crystalline red phosphorus (cRP), dcharacterized by its layered and fibrous structure, lends itself readily to the production of nanoribbons. Our study demonstrates a robust method for achieving high-yield, high-quality cRP by concurrently introducing mineralizing agent I2 and Si wafers into the Chemical Vapor Transport (CVT) synthesis process. Through ultrasound assistance, we transformed high-quality cRP into crystalline red phosphorus nanoribbons (cRP NRs) with an average thickness ranging from 7.5 to 17.5nm and an average width between 75 and 175nm. cRP NRs (I2 and Si) showcased impressive degradation capabilities towards Methyl Orange (MO) and Tetracycline (TC), achieving a remarkable 99% degradation of MO within 18min under the simulated visible-light irradiation. The reactive species capturing experiments confirmed that ·O2- was the primary active agent responsible for the photocatalytic degradation of MO.

Construction of ZnCo2O4/Ag3PO4 composite photocatalyst for enhanced photocatalytic performance

AbstractIn this study, ZnCo2O4/Ag3PO4 composite catalyst was prepared by the precipitation method, and their performance in the photocatalytic degradation of methyl orange (MO) was studied. The catalysts were characterized by scanning electron microscopy, high‐resolution transmission electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, selected area electron diffraction, X‐ray photoelectron spectroscopy, and UV‐Vis diffuse reflectance spectroscopy. The results indicate that the 0.1 ZnCo2O4/Ag3PO4 composite system has good photocatalytic activity in the degradation of methyl orange. Under simulated sunlight conditions, the degradation rate can reach 94% after 30 min. The maximum reaction rate constant of 0.1 ZnCo2O4/Ag3PO4 was 0.05301 min−1, which is 3 times and 52 times the rate constant of pure Ag3PO4 and pure ZnCo2O4, respectively. In catalyst recycling experiments, 0.1 ZnCo2O4/Ag3PO4 still degraded methyl orange at a rate of 84.4% after three cycles. Trapping experiments showed that holes and superoxide radicals mostly contributed to the photocatalytic degradation of methyl orange by the catalyst, while hydroxyl radicals played a partial role. The energy level structure of ZnCo2O4/Ag3PO4 is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. In the investigated catalyst series, 0.1 ZnCo2O4/Ag3PO4 demonstrated the best photocatalytic performance.

Enhanced Photocatalytic Degradation of Methyl Orange by Metal‐Tio2 Nanoparticles

AbstractIn this study, a series of transition metal‐doped TiO2 was prepared by a simple sol‐solvothermal method. Mix an ethanol solution of tetrabutyl titanate and metal nitrate solution to obtain a homogeneous sol, which is then subjected to solvothermal treatment. After calcination, the metal‐TiO2 naoncomposite was obtained. Selected transition metal precursors, including Cu, Fe, Ag, Cr, Co and Zn, were doped into TiO2 nanocatalysts to assess photocatalytic degradation activities. The results show that 1 mol % Ag−TiO2 photocatalyst has a larger specific surface area, a stable anatase phase and the narrowest forbidden band energy (3.00 eV). In photocatalytic degradation of methyl orange (MO) tests, 1 mol % Ag−TiO2 could reach 100 % decolourisation after 70 min and 75.43 % mineralisation after 90 min. ESR analysis confirmed that Ag doping significantly increased the content of ⋅O2− and ⋅OH for the TiO2 catalyst, which are responsible for the oxidation reactions and consequently degradation of pollutants. The photocatalytic degradation mechanism of MO was also proposed. The TOC analyses confirmed the mineralization of MO. The excellent thermal and chemical stability of 1 mol % Ag−TiO2 has also been demonstrated by thermogravimetric analysis and cycling experiments. Electrochemical tests have also demonstrated the excellent electrochemical properties of 1 mol % Ag−TiO2.

Ta2O5 coatings modified with CdS, ZnO, and Dy2O3 particles prepared by plasma electrolytic oxidation of tantalum for the photocatalytic degradation of methyl orange

Ta2O5/CdS, Ta2O5/ZnO and Ta2O5/Dy2O3 coatings for application in photocatalytic degradation of methyl orange were prepared by plasma electrolytic oxidation of tantalum in an alkaline electrolyte with different concentrations of CdS, ZnO, and Dy2O3 particles up to 2.0 g/L. The coatings were characterized by SEM/EDS, XRD, Raman spectroscopy, DRS and photoluminescence spectroscopy. The morphology, thickness, phase structure and absorption properties of all coatings are almost identical and independent of the content of CdS, ZnO, and Dy2O3 embedded in Ta2O5 coatings. The orthorhombic and monoclinic phases of Ta2O5 are the main constituents of the coatings. Due to the low content of embedded CdS, ZnO, and Dy2O3 in Ta2O5 coatings, they exhibit high absorption in the middle ultraviolet region, which is characteristic of Ta2O5. The photocatalytic activity (PA) of Ta2O5/CdS, Ta2O5/ZnO and Ta2O5/Dy2O3 is higher than that of pure Ta2O5 and depends on the amount of CdS, ZnO, and Dy2O3 in the electrolyte, respectively. The highest PA was observed for coatings formed in an electrolyte containing 0.5 g/L of CdS, ZnO, and Dy2O3. The improved PA of Ta2O5/CdS, Ta2O5/ZnO and Ta2O5/Dy2O3 compared to Ta2O5 is related to the reduction of photogenerated electron/hole recombination. The mechanism of the photogenerated electron/hole transfer process is presented and discussed.

Synthesis of Zr-doped CeO2 nanoparticles for photocatalytic degradation of methyl orange and electrochemical properties

Synthesis of Zr-doped CeO2 nanoparticles for photocatalytic degradation of methyl orange and electrochemical properties

Photocatalytic degradation of methyl orange by a Pt(II) complex under visible light irradiation

An extremely effective photocatalytic complex, PtLCl2 (1), was synthesized with (4-([2,2':6',2''-terpyridin]-4'-yl)phenyl)boronic acid as ligand and further characterized through single crystal X-ray diffraction, X-ray photoelectron spectroscopy and UV-vis spectrum. Multipoint hydrogen bonds and three kinds of π-π stacking interactions are observed in the supramolecular structure of 1. More significantly, the Pt(II) complex exhibits outstanding photocatalytic degradation efficiency (94.76%) for methyl orange within 120 min under visible light irradiation. The kinetic rate constant (k) for 1 (10 mg) is 0.02505 min−1, which is approximately 70 times higher than that of the ligand (0.00036 min−1). Moreover, its photocatalysis mechanism proposed that ·O2 − and h+ were the main active species for MO degradation, providing a great prospect for development of a new efficient photocatalytic complex.

Photocatalytic degradation of methyl orange and methyl violet dyes by UV/Cu2+/PDS process

ABSTRACT This research is focused on the application of the UV/Cu2+/peroxydisulfate (PDS) system for the successful decolorization of methyl orange (MO) and methyl violet (MV) dyes in aqueous media. The effects of different parameters such as the equilibrium time, initial catalyst amount, PDS concentration and pH of the media in terms of MO and MV degradation were studied. Furthermore, the photocatalytic performance of the UV/Cu2+/PDS system was also investigated by performing the degradation of MO and MV in different water systems including distilled water, synthetic wastewater and industrial wastewater samples. The results revealed 94 and 89% degradation for MO and MV dyes in the UV/Cu2+/PDS system, respectively. The radical quenching experiments showed sulfate radicals (SO4·-) as the prominent species involved in the degradation of MO and MV dyes. Overall, it was concluded that the UV/Cu2+/PDS process has the ability to be adopted for the effective elimination of contaminants from the aquatic system.

Eco-friendly synthesis of N- cholyl mercapto histidine capped silver nanoparticles and its sensing of mercury (II) ions and photo catalytic degradation of methyl orange

In this report, we have developed highly water soluble and stable silver nanoparticles (Ag NPs) utilizing N-Cholyl Mercapto Histidine (NCMH) as a reducing and stabilizing agent with near the primary critical micellar concentration (CMC) under ambient sunlight irradiation. Moreover, The NCMH was firstly synthesized by demonstrating the reaction between cholic acid and 2- Mercapto Histidine through a simple acid amine coupling approach. The primary and secondary CMC of NCMH surfactant was measured by pyrene (1 × 10−6 M) as a fluorescent probe, and values were found to be 3.2 and 13.1 mM respectively. The synthesized Ag NPs showed at neutral pH and highly stable for more than one year without any noticeable aggregation. The TEM analysis displays the synthesized Ag NPs having a spherical shape and average size of 9.6 ± 0.5 nm. The synthesis of stabilized Ag NPs was used for ultra-sensitive and selective detection of Hg2+ ions in aqueous medium were monitored by Uv–visible spectrometer and naked eyes with a lowest limit of detection (LOD) 7 nM. The photo-catalytic degradation of methyl orange (MO) by utilizing Ag NPs as nano-catalyst exhibits a potential degradation within a study period of 180 min. Concluding that, facile and cost effective green synthesis of NCMH capped Ag NPs possess excellent reducing ability towards the selective detection of Hg2+ ions along with photo-catalytic degradation of MO dye. These true findings detached an innovative pathway of Ag NPs towards the reactivity against the catalytic activity of dye degradation and selective sensing of Hg2+ ions. Thus it paves the way for extensive range of novel potential applications of Ag NPs in various environment friendly approaches of sensitive and analytical protocol in the future.

Preparation and photocatalytic performance of BiOCl nanosheet–TiO2 nanotube array composites

Combining BiOCl with TiO2 nanomaterials is beneficial to enhance the photocatalytic activity and optoelectronic activity. In this paper, BiOCl nanosheet–TiO2 nanotube array composites were synthesized to enhance the photocatalytic degradation performance for methyl orange (MO) of TiO2 under ultraviolet light irradiation. BiOCl nanosheets were deposited on TiO2 nanotube arrays by the straightforward impregnation method. X-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and photocurrent (i–t) were used to evaluate the composites of BiOCl nanosheets–TiO2 nanotube arrays. The results showed that the tetragonal BiOCl nanosheets clustered together on the surface of the TiO2 nanotubes and grew along the (110) crystal plane. The composites outperformed pure TiO2 regarding outstanding structure and overall photocatalytic performance, and the MO photocatalytic degradation rate was 98.5%. For the 30-BiOCl–TiO2, its photocurrent intensity (58 µA) was 4.5 higher than TiO2 (13 µA). The degradation rate of 87% can still be reached after three cycles.

An Efficient p-n Heterojunction Copper Tin Sulfide/g-C3N4 Nanocomposite for Methyl Orange Photodegradation.

The discharge of toxic dye effluents from industry is a major concern for environmental pollution and toxicity. These toxic dyes can be efficiently removed from waste streams using a photocatalysis process involving visible light. Due to its simple synthesis procedure, inexpensive precursor, and robust stability, graphitic carbon nitride (g-C3N4, or CN) has been used as a visible light responsive catalyst for the degradation of dyes with mediocre performance because it is limited by its low visible light harvesting capability due to its wide bandgap and fast carrier recombination rate. To overcome these limitations and enhance the performance of g-C3N4, it was coupled with a narrow bandgap copper tin sulfide (CTS) semiconductor to form a p-n heterojunction. CTS and g-C3N4 were selected due to their good stability, low toxicity, ease of synthesis, layered sheet/plate-like morphology, and relatively abundant precursors. Accordingly, a series of copper tin sulfide/graphitic carbon nitride nanocomposites (CTS/g-C3N4) with varying CTS contents were successfully synthesized via a simple two-step process involving thermal pyrolysis and coprecipitation for visible-light-induced photocatalytic degradation of methyl orange (MO) dye. The photocatalytic activity results showed that the 50%(wt/wt) CTS/g-C3N4 composite displayed a remarkable degradation efficiency of 95.6% for MO dye under visible light illumination for 120 min, which is higher than that of either pristine CTS or g-C3N4. The improved performance is attributed to the extended light absorption range (due to the optimized bandgap), effective suppression of photoinduced electron-hole recombination, and improved charge transfer that arose from the formation of a p-n heterojunction, as evidenced by electrochemical impedance spectroscopy (EIS), photocurrent, and photoluminescence results. Moreover, the results of the reusability study showed that the composite has excellent stability, indicating its potential for the degradation of MO and other toxic organic dyes from waste streams.

Preparation of Fe3O4@SiO2@N-TiO2 and Its Application for Photocatalytic Degradation of Methyl Orange in Na2SO4 Solution

In this paper, Fe3O4@SiO2@TiO2 and N-doped Fe3O4@SiO2@N-TiO2 photocatalysts with magnetic core-shell structures were prepared using a multi-step synthesis method. The materials were analyzed using various techniques, such as X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), selected-area electron diffraction patterns (SAED), and X-ray photoelectron spectroscopy (XPS). The results indicated that the prepared samples had an anatase structure, and N was successfully doped. Fe3O4@SiO2@TiO2 and Fe3O4@SiO2@N-TiO2 with different amounts of nitrogen doping were used for the study of photocatalytic degradation of methyl orange (MO) in pure MO solution, and in MO and Na2SO4 (MO-Na2SO4) mixed solution, respectively. The average photocatalytic degradation rate of MO in pure MO solution with three different batches each of Fe3O4@SiO2@TiO2 and Fe3O4@SiO2@N-TiO2 (3 mL of NH4OH used for doping) under high-pressure mercury lamp irradiation reached 85.25% ± 2.23% and 95.53% ± 0.53%, respectively. The average photocatalytic degradation rate of MO in the MO-Na2SO4 mixed solution with three different batches each of Fe3O4@SiO2@TiO2 and Fe3O4@SiO2@N-TiO2 (3 mL of NH4OH used for doping) under the same irradiation condition reached 90.46% ± 3.33% and 97.79% ± 2.09%, respectively. The results showed that Na2SO4 can promote photocatalytic degradation of MO. The experiment of recycling photocatalysts showed that there was still a good degradation effect after five cycles. Finally, the first-order kinetic model and the photocatalytic degradation mechanism were investigated.

Scrutinizing the influence of vanadium (V5+) in Gd:MgO nanoparticles in their physicochemical properties and photocatalytic properties

Using a simple precipitation technique the preparation of V doped Gd:MgO nanoparticles are successfully achieved. Using various conventional characterization methodologies the microscopic structure, morphological and physicochemical characteristics of the synthesized particles were analyzed. Observed optical bandgap of the material lays in UV region hence photocatalytic experiments were carried out using UV light illumination. Toxic textile dye namely methyl orange (MO) and methylene blue (MB) was used as model pollutant. Among the synthesized nanoparticles 5 wt% V doped Gd:MgO performed well in photocatalytic degradation of MO and MB dye. Surface charge of the prepared photocatalyst (point of zero charge PZC) was analyzed by salt titration method. pH influence in the degradation process was scrutinized by maintaining different pH values.