Methyl Orange Dye Research Articles

Direct Z-scheme heterojunction impregnated MoS2–NiO–CuO nanohybrid for efficient photocatalyst and dye-sensitized solar cell

In this present work, the preparation of ternary MoS2–NiO–CuO nanohybrid by a facile hydrothermal process for photocatalytic and photovoltaic performance is presented. The prepared nanomaterials were confirmed by physio-chemical characterization. The nanosphere morphology was confirmed by electron microscopy techniques for the MoS2–NiO–CuO nanohybrid. The MoS2–NiO–CuO nanohybrid demonstrated enhanced crystal violet (CV) dye photodegradation which increased from 50 to 95% at 80 min; The degradation of methyl orange (MO) dye increased from 56 to 93% at 100 min under UV–visible light irradiation. The trapping experiment was carried out using different solvents for active species and the Z-Scheme photocatalytic mechanism was discussed in detail. Additionally, a batch series of stability experiments were carried out to determine the photostability of materials, and the results suggest that the MoS2–NiO–CuO nanohybrid is more stable even after four continuous cycles of photocatalytic activity. The MoS2–NiO–CuO nanohybrid delivers photoconversion efficiency (4.92%) explored efficacy is 3.8 times higher than the bare MoS2 (1.27%). The overall results indicated that the MoS2–NiO–CuO nanohybrid nanostructure could be a potential candidate to be used to improve photocatalytic performance and DSSC solar cell applications as well.

Radiant synergy: Illuminating methyl orange dye removal with g-C3N4/ZnO heterojunction photocatalyst

In this study, a robust hybrid heterojunction composite of g-C3N4/ZnO was successfully synthesized using a straightforward and cost-effective coprecipitation method. The resulting composite amalgamates the properties of graphitic carbon nitride (g-C3N4) and zinc oxide nanoparticles (ZnO NPs). Thorough characterization using techniques such as XRD, FT-IR, FE-SEM, HR-TEM, UV-DRS, EIS, PL, and EDX confirmed the structural and elemental composition of the catalyst. The challenge of using photons as the sole energy source for the activation of photocatalysts under ambient conditions was addressed. The photocatalytic potential of the hybrid heterojunctions was assessed by degrading the methyl orange (MO) dye under sunlight. The 10 wt% g-C3N4/ZnO composite exhibited effective suppression of charge recombination during photocatalytic degradation. Notably, the heterojunction 10 wt% g-C3N4/ZnO composite displayed remarkable photocatalytic performance, achieving a substantial 98 % degradation of MO within 90 min of solar irradiation, outperforming other materials. Moreover, the synthesized composites exhibited favorable attributes in terms of recyclability and mechanical stability, retaining their efficacy over five cycles. This substantiates their promising role as potential candidates for future photocatalyst applications. In essence, g-C3N4/ZnO heterojunction composites offer a robust solution for efficient and sustainable photocatalytic degradation of organic pollutants.

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.

Removal of methyl orange dye by high surface area biomass activated carbon prepared from bamboo fibers

To obtain a green biomass-activated carbon with abundant pores for the high-efficiency removal of dye, this study fabricated bamboo fiber-based activated carbons (BFACs) via a one-step activation strategy with the assistance of ZnCl2 as the activator for the removal of methyl orange (MO). The results showed that the specific surface area (SSA) of BFAC-500 activated at 500 ℃ was as high as 2512 m2/g with a total pore volume (Vtotal) of 1.411 cm3/g. The adsorption kinetics and thermodynamics of MO conformed to the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. Based on the Langmuir fitting results, the theoretical maximum adsorption capacity (Qm) of MO adsorbed by BFAC-500 was calculated to be 591.71 mg/g at 318 K, pH=4.5, 0.4 g/L, with an equilibrium time of about 60 min. According to the thermodynamic calculation, the value of ΔH0 was less than 40 kJ/mol, which indicates that the adsorption mechanism was mainly based on physical adsorption, and based on the BET, Zeta potential, FTIR, and XPS before and after the adsorption, it was further known that it was mainly characterized by pore filling, electrostatic adsorption, hydrogen bonding, and π-π interactions. Moreover, when pH < pHzpc, the surface of BFAC-500 was positively charged and the adsorption of Cl-, SO42- and PO43- on MO had little effect; when pH>pHzpc, the surface was negatively charged and the adsorption of BFAC-500 on MO was enhanced by Na+, K+, and Mg2+. The BFAC materials in this study have promising applications in the practical removal of MO dyes.

A facile green synthesis of manganese oxide nanoparticles using gum karaya polymer as a bioreductant for efficient photocatalytic degradation of organic dyes and antibacterial activity

The release of organic dyes into water systems, mainly textile industries, poses a significant threat to human and animal health. This approach shows great potential for effectively removing harmful dyes and microorganisms from wastewater treatment for environmental remediation. This study utilized gum karaya polymer bio-reductant to synthesize manganese oxide (MnO2) nanoparticles through a green approach. The synthesized MnO2 nanoparticles were characterized and confirmed by various analytical techniques. These results revealed their nanoscale dimensions, morphology, chemical purity, crystal nature, decolorized intermediate, and band gap. The photocatalytic degradation of hazardous Congo red and methyl orange dyes using KRG-MnO2 nanoparticles under visible light irradiation. Furthermore, the results demonstrated that Congo red dye degradation efficiency of 93.34 % was achieved. The dye concentration (8 to 16 mg/L), pH concentration, and radical trapping were studied. This suggests that holes and hydroxyl radicals play a crucial role in degrading the Congo red dye and demonstrate superior recyclability after three successive cycles and good stability. The possible intermediates from the Congo red dye degradation were identified through LC-MS analysis. The polymer composite MnO2 NPs have displayed notable antibacterial activity against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. The research indicates that MnO2 nanoparticles functionalized with polymers can efficiently remove pathogens and organic dyes from diverse industrial water treatment processes.

Degradation of methyl orange using hydrodynamic cavitation coupled with plasma oxidation and ultraviolet C

Combining multiple advanced oxidation processes (AOPs) is essential for the efficient treatment of dye wastewater. In this study, the degradation efficiencies of various oxidation methods, including hydrodynamic cavitation (HC), dielectric barrier discharge (DBD) plasma oxidation, ultraviolet C (UVC), and their combination HC + DBD + UVC, were investigated for Methyl Orange (MO). The photolysis of ozone (O3) and the degradation mechanism associated with HC + DBD + UVC were analyzed to elucidate the pathway of MO degradation. The results demonstrated that the combination of HC + DBD + UVC exhibited a significantly enhanced degradation efficiency compared to other process combinations, achieving a removal efficiency exceeding 91% within a 5-min timeframe. Optimal parameters for achieving a 99.5% degradation rate of 10 mg/L MO were determined as follows: pH 4, inlet pressure of 1.5 MPa, utilization of eight UV lamps with a power input of 46.11 W. During the degradation process, hydroxyl radicals (·OH) and ozone (O3) played crucial roles, while the incorporation of UV lamps effectively mitigated ozone (O3) emissions and enhanced the oxidation of ozone (O3). In conjunction with the analysis of degradation products using liquid chromatography-mass spectrometry, it is highly probable that the MO degradation pathway involves reductive cleavage of the azo bond through ·OH attack. Compared to other experimental methods in literature, HC + DBD + UVC exhibits significant advantages such as enhanced efficiency and absence of additives. This innovative approach offers a rapid and practical on-site solution for efficient MO dye wastewater treatment.

Isothermal and kinetic screening of methyl red and methyl orange dyes adsorption from water by Delonix regia biochar-sulfur oxide (DRB-SO)

In this study, Delonix regia seed pods (DRSPs) as a locally available material were refluxed in 90% H2SO4 to yield a novel D. regia seed pods biochar-sulfur oxide (DRB-SO). FTIR, BET, BJH, SEM, EDX, XRD, DSC and TGA were applied to investigate the characterizations of the prepared DRB-SO. Various adsorption parameters like pH effect, dye concentration effect, adsorbent dose, reaction time isotherm and kinetic study were carried out to explain the process of adsorption of methyl orange (MO) and methyl red (MR) onto DRB-SO. Langmuir's adsorption model perfectly explained the adsorption process onto the surface of DRB-SO as a monolayer. The maximum adsorption efficiency of DRB-SO was (98%) and (99.6%) for MO and MR respectively which attained after 150 min with an adsorbent dose of 0.75 g/L. The pseudo-second-order kinetic model best explained the process of adsorption of MO and MR dyes by DRB-SO. The highest observed adsorption amount was as high as 144.9 mg/g for MO dye and 285.7 mg/g for MR dye, comparable with other reported materials based on activated carbon materials. All of the outcomes signposted a prodigious perspective of the fabricated biochar composite material in wastewater treatment. Using the regenerating DRB-SO through an acid–base regeneration process, six cycles of adsorption/desorption were examined. Over the course of the cycles, there was a minor decrease in the adsorption and desorption processes. Also, it was revealed what the most plausible mechanism was for DRB-SO to absorb the ions of the MO and MR dyes.

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.

Chemical vs biological silver nanoparticles: Synthesis, characterization, properties, and in vitro applications

The rise of silver nanoparticles (AgNPs) has been exponential traversing through different synthesis approaches and spread across diverse scientific and technological fields. Past decade, the application of different biological materials or systems in the synthesis of AgNPs has generated much needed impetus to drive the AgNPs synthesis through ecofriendly and economical synthesis processes. The present study aims to compare the conventional (chemical approach) and biological synthesis approach. Here in, the as-synthesized silver nanoparticles (AgNPs) via chemical (Che-AgNPs) and biological (Bio-AgNPs) methods were characterized for their optical, physicochemical, crystalline, and elemental composition properties. Che-AgNPs and Bio-AgNPs showed a peak at 455 nm and 415 nm with average particle size of 198.73 nm and 135.19 nm, whereas surface charge was found to be −21.94 mV and –32.67 mV, respectively. Che-AgNPs have shown better zone of inhibition (ZOI) against gram- bacteria such as Escherichia coli (10.57 mm), Klebsiella pneumoniae (11.25 mm), Pseudomonas aeruginosa (15.43 mm), whereas Bio-AgNPs showed better ZOI against gram + bacteria such as Bacillus subtilis (13.31 mm), Coagulase-negative staphylococci (12.28 mm), Staphylococcus aureus (12.03 mm) at 50 µg per well concentration. Che-AgNPs showed better anticancer (IC50 value in µg/ml) potential compared to Bio-AgNPs against K562 (60.60 and 109.96), HeLa (67.26 and 129.31), A549 (48.94 and 105.38) cancer cells, whereas Bio-AgNPs showed minimum toxicity towards MCF-10A normal cells. Bio-AgNPs showed better photocatalytic activity compared to Che-AgNPs against methyl red (95 % and 70 %), methylene blue (64 % and 93 %), rhodamine-B (81 % and 96 %), methyl orange (76 % and 97 %), and malachite green (62 % and 97 %) dyes under 4, 9, 7, 4, and 9 min, respectively. Furthermore, Bio-AgNPs were studied for possible involvement of reactive species and their recyclability.

Assessment of Biodegradation and Phytotoxicity of Azo Dyes Methyl Orange and Crystal Violet by Escherichia coli and Bacillus subtilis

Azo dyes are widely used colourants, possess array of colours and are generally recalcitrant to microbial degradation. This study aimed to isolate azo dyes degrading bacteria from soil; treat methyl red and crystal violet dyes using the isolates, and assess the phytotoxicity of the treated and untreated dyes on sorghum. Ten bacteria were isolated from the soil, of which two were identified as efficient azo dyes degrading bacteria by efficiency in dye decolouration. The isolates were identified as Escherichia coli and Bacillus subtilis based on their biochemical characteristics. The isolates were able to degrade methyl orange dye by 16-75 % and crystal violet by 16-78%, depending on the concentration of the dye. The isolates were more efficient at degrading the dyes at a low concentration of 0.00025 mg/ml, as indicated by a higher percentage of decolourization (53-79%). The percentage phytotoxicity of the untreated methyl red ranged from 33-59%, while the toxicity of the untreated crystal violet ranged from 62-91%. The toxicity of the treated methyl red ranged from 9-34%, while the toxicity of the treated crystal violet ranged from 12-32%. The results revealed that the isolates were capable of degrading methyl red and crystal violet dyes, and could be useful in the bioremediation of azo dyes polluted soil.

Chitosan/polyvinyl acetate/manganese ferrite as a eco-friendly adsorbent for separation of methyl orange dye from aqueous solution

This study presents a novel approach in the field of wastewater treatment, focusing on the development of an eco-friendly magnetic adsorbent, CS/PVAc/MnFe2O4, for the efficient removal of methyl orange (MO) from aqueous solutions. The combination of chitosan, polyvinyl acetate, and manganese ferrite demonstrated a remarkable MO removal efficiency of 96.7% in just 75 min at a pH = 3, utilizing only 0.03 g of adsorbent and 50 mg/L of MO. The material was thoroughly characterized using FT-IR, XRD, SEM, and VSM techniques, confirming its effectiveness. The study successfully applied the Langmuir isotherm and pseudo-second-order kinetics models to describe the adsorption isotherms and kinetics, revealing a maximum adsorption capacity of 80.58 mg/g. The findings underscore the potential of CS/PVAc/MnFe2O4 as a cost-effective and efficient solution for wastewater treatment, particularly in the removal of organic contaminants. This research contributes to the advancement of adsorbent materials and recommends further exploration for industrial applications and development.

A Comparative Study on the Degradation of Methylene Blue and Methyl Orange Dyes Under the Irradiation of Visible Light Using GO–CdO Nanocomposites

Cadmium oxide nanoparticles synthesized from alcoholic method using cadmium chloride monohydride and the composites with GO by simple dispersion method. Two nanocomposites with 5 Wt% and 10 Wt% loading of CdO over GO were prepared and named as GC1 and GC2 respectively. From XRD the CdO nanoparticles were of crystalline nature and were indexed to JCPDS card no: 05-0640 corresponding to Cubic lattice system. The particle like morphology of the CdO was confirmed by SEM and TEM. The decoration of monolayer GO sheets by CdO nanoparticles was unveiled through these studies. The Raman analysis reveals the presence of D and G peaks in the composites with an increased ID/IG ratio. UV-Vis study displays the absorption edge of CdO and a redshift is observed for GC2. From PL study, emission peak occurs at 358 nm for composites along with a quenching of intensity for GC2. The TG-DT analysis reveals the thermal stability of pristine and nanocomposites. Photocatalytic degradation of the as synthesized samples was studied for Methylene orange and Methylene blue dye using a Xenon lamp with 500 W. The degradation of the GC2 happens in 90 minutes with degradation efficiency 73% of was achieved for Methyl Orange dye. For Methylene blue the GC2 sample degrades only in 30 minutes with an efficiency of 94% was achieved.

A feasible approach for azo-dye (methyl orange) degradation by textile effluent isolate Serratia marcescens ED1 strain for water sustainability: AST identification, degradation optimization and pathway hypothesis

Methyl orange (MO) is a dye commonly used in the textile industry that harms aquatic life, soil and human health due to its potential as an environmental pollutant. The present study describes the dye degradation ability of Serratia marcescens strain ED1 isolated from textile effluent and characterized by 16S rRNA gene sequence analysis. The laccase property of bacterial isolate was confirmed qualitatively. The effects of various factors (pH, temperature, incubation time, and dye concentration) were evaluated using Response Surface Methodology (RSM). The maximum dye (MO) degradation was 81.02 % achieved at 37 °C temperature and 7.0 pH with 200 mg/L dye concentration after 48 h of incubation. The beef extract, ammonium nitrate and fructose supplementation showed better response during bioremediation among the different carbon and nitrogen sources. The degree of pathogenicity was confirmed through the simple plate-based method, and an antibiotic resistance profile was used to check the low-risk rate of antibiotic resistance. However, the fate and extinct of degraded MO products were analysed through UV–Vis spectroscopy, FT-IR, and GC-MS analysis to confirm the biodegradation potential of the bacterial strain ED1 and intermediate metabolites were identified to propose metabolic pathway. The phytotoxicity study on Vigna radiata L. seeds confirmed nontoxic effect of degraded MO metabolites and indicates promising degradation potential of S. marcescens strain ED1 to successfully remediate MO dye ecologically sustainably.

Fagonia arabica extract-stabilized gold nanoparticles as a highly selective colorimetric nanoprobe for Cd2+ detection and as a potential photocatalytic and antibacterial agent

In the current study, polar leaves extract of the plant Fagonia arabica (FALE) from the Zygophyllaceae family was used to synthesize sunlight-assisted gold nanoparticles (FALE@AuNPs) with defined size and shape and of excellent colloidal stability. The effect of different physiochemical parameters (FALE dosage, Au3+ ions concentration, sunlight exposure time) on the formation of AuNPs was also studied. The synthesized FALE@AuNPs were characterized using UV–visible spectrophotometry, scanning electron microscopy-energy dispersive X-rays (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), powder XRD, zeta potential (ZP) and dynamic light scattering (DLS). The successful synthesis of FALE@AuNPs in solution was confirmed by the appearance of a localized surface plasmon resonance (LSPR) characteristic peak at 535 nm in UV–Vis spectra. The size estimated by UV–Vis (∼59 nm) was found in good agreement with that determined by SEM (∼60 nm) and DLS (∼61 nm). A zeta potential value of -28±1.5 mV confirms the colloidal stability of FALE@AuNPs. The FALE@AuNPs were utilized as a colorimetric nano-sensor for Cd2+ ion 15 nM limit of detection (LOD) and linear range detection of 0–600 nM. When utilized to identify Cd2+ ion in actual water samples, the nano-probe demonstrated high recovery rates of over 98 % and a low relative standard deviation (RSD) of about 4 %, demonstrating its dependability and efficiency in doing so. FALE@AuNPs were found to be antibacterial against gram-positive as well as gram-negative bacteria. An exceptionally high photocatalytic activity was shown by FALE@AuNPs with 80 % efficiency of degradation examined against methylene blue and methyl orange dye.

Cellulose acetate, a source from discarded cigarette butts for the development of mixed matrix loose nanofiltration membranes for selective separation

This study presents an environmentally friendly method for extracting cellulose acetate (CA) from discarded cigarette filters, which is then utilized in the fabrication of cellulose-based membranes designed for high flux and rejection rates. CA membranes are likeable to separate dyes and ions, but their separation efficiency is exposed when the contaminant concentration is very low. So, we have integrated graphene oxide (GO) and carboxylated titanium dioxide (COOH-TiO2) in CA to develop mixed matrix membranes (MMMs) and studied them against dyes and most used salts. The CA has been extracted from these butts and added GO and COOH-TiO2 nanoparticles to develop MMMs. The present work administers the effective separation of five dyes (methyl orange, methyl violet, methylene blue, cresol red, and malachite green) and salts (NaCl and Na2SO4) along with the high efficiency of water flux by prepared CA membranes. The prepared membranes rejected up to 94.94 % methyl violet, 91.28 % methyl orange, 88.28 % methylene blue, 89.91 % cresol red, and 91.70 % malachite green dye. Along with the dyes, the membranes showed ∼40.40 % and ∼ 42.97 % rejection of NaCl and Na2SO4 salts, respectively. Additionally, these membranes have tensile strength up to 1.54 MPa. Various characterization techniques were performed on all prepared CA membranes to comprehend their behaviour. The antibacterial activity of MMMs was investigated using the Muller-Hinton-Disk diffusion method against the gram-positive bacterium Staphylococcus aureus (S. aureus) and the gram-negative bacterium Escherichia coli (E. coli). We believe the present work is an approach to utilizing waste materials into valuable products for environmental care.

2D/2D SnOx/TiO2 Z-scheme heterojunction with oxygen vacancies for boosted photocatalytic performance and mechanistic insight

A Z-Scheme heterojunction two-dimensional/two-dimensional (2D/2D) SnOx/TiO2 photocatalyst modified with oxygen vacancies (OVs) was successfully prepared using a hydrothermal method. Compared with SnOx and TiO2, the optimized SnOx/TiO2 heterojunction exhibited significantly higher photocatalytic activity for degrading methyl orange (MO). The apparent reaction rate of the SnOx/TiO2 heterostructure under visible light illumination reached 1.8355 min−1, approximately 15.74 times higher than that of SnOx alone. The results confirmed the presence of abundant oxygen vacancies on SnOx/TiO2, which acted as electron traps accelerating electron transfer. Furthermore, analyses including UPS, ESR, and reactive active species trapping experiments indicating a Z-scheme heterojunction were presented between SnOx and TiO2. According to density functional theory (DFT) calculations, the energy bands’ alignment enabled the Z-scheme heterojunction formation, while the inherent electric field drove the reaction. The experimental and computational findings demonstrated that the combined influence of the Z-Scheme heterojunction and OVs enhanced the photocatalytic reaction mechanism, facilitating efficient electron transport and preserving charge carriers with excellent redox capability. And a possible mechanism degradation pathway of MO dye is proposed. This study serves as a source of inspiration for future endeavors in the design and development of Z-Scheme heterojunction photocatalysts incorporating oxygen vacancies, with the aim of achieving enhanced efficiency in environmental remediation processes.

Remediation of Methyl Orange Dye in Aqueous Solutions by Green Microalgae (Bracteacoccus sp.): Optimization, Isotherm, Kinetic, and Thermodynamic Studies

Remediation of Methyl Orange Dye in Aqueous Solutions by Green Microalgae (Bracteacoccus sp.): Optimization, Isotherm, Kinetic, and Thermodynamic Studies

Advancing photocatalytic activity through a green route: Bismuth ferrite@molybdenum trioxide heterostructure for sustainable water treatment

Photocatalysis has become increasingly pervasive in the chemical industry, profoundly impacting operational costs. However, an ideal photocatalyst must possess characteristics such as excellent reactivity, high selectivity, prolonged stability, low toxicity, and cost-effectiveness. Moreover, it should facilitate the efficient separation of photo-generated charge carriers, thereby minimizing recombination rates. In pursuit of advancing photocatalytic activity for sustainable water treatment, this investigation focused on synthesizing a groundbreaking photocatalyst, the Bismuth Ferrite@Molybdenum trioxide heterostructure, using an eco-friendly green chemistry technique with pomegranate extract. This approach aligns with the goal of environmental sustainability and represents a novel contribution to the field. Employing a comprehensive approach, advanced characterization techniques such as XRD, SEM, FT-IR, and UV–Vis were applied to analyze the material's structural, morphological, and optical properties. According to the characterization results, the heterostructure demonstrates superior photocatalytic efficiency, heightened crystallinity, and reduced recombination rates during dye degradation for water treatment compared to both individual photocatalysts. Notably, the composite catalyst exhibits a synergistic impact, outperforming individual BiFeO3 and MoO3 photocatalysts. SEM observations confirm the successful integration of rod-like MoO3 and cylindrical BiFeO3 morphologies, highlighting the strategic combination achieved through the green chemistry route. Furthermore, UV–Vis spectroscopy reveals key optical parameters, emphasizing a narrow bandgap energy of 2.74 eV with a high refractive index of 2.43 eV. The exceptional efficacy of the heterostructure in degrading dyes within the visible spectrum, surpassing expectations within a 4-hour timeframe, highlights its efficiency and precision. Remarkably, achieved degradation rates for Rhodamine B dye (98 %), Methyl Blue (96 %), and Methyl Orange dye (95 %) highlights the promising role of proposed photocatalytic system in effectively addressing water pollutant challenges.

Horseradish Peroxidase Immobilized onto Mesoporous Magnetic Hybrid Nanoflowers for Enzymatic Decolorization of Textile Dyes: A Highly Robust Bioreactor and Boosted Enzyme Stability.

Recently, hybrid nanoflowers (hNFs), which are accepted as popular carrier supports in the development of enzyme immobilization strategies, have attracted much attention. In this study, the horseradish peroxidase (HRP) was immobilized to mesoporous magnetic Fe3O4-NH2 by forming Schiff base compounds and the HRP@Fe3O4-NH2/hNFs were then synthesized. Under optimal conditions, 95.0% of the available HRP was immobilized on the Fe3O4-NH2/hNFs. Structural morphology and characterization of synthesized HRP@Fe3O4-NH2/hNFs were investigated. The results demonstrated that the average size of HRP@Fe3O4-NH2/hNFs was determined to be around 220 nm. The ζ-potential and magnetic saturation values of HRP@Fe3O4-NH2/hNFs were -33.58 mV and ∼30 emu/g, respectively. Additionally, the optimum pH, optimum temperature, thermal stability, kinetic parameters, reusability, and storage stability were examined. It was observed that the optimum pH value shifted from 5.0 to pH 8.0 after immobilization, while the optimum temperature shifted from 30 to 80 °C. K m values were calculated to be 15.5502 and 7.6707 mM for free HRP and the HRP@Fe3O4-NH2/hNFs, respectively, and V max values were calculated to be 0.0701 and 0.0038 mM min-1. The low K m value observed after immobilization indicated that the affinity of HRP for its substrate increased. The HRP@Fe3O4-NH2/hNFs showed higher thermal stability than free HRP, and its residual activity after six usage cycles was approximately 45%. While free HRP lost all of its activity within 120 min at 65 °C, the HRP@Fe3O4-NH2/hNFs retained almost all of its activity during the 6 h incubation period at 80 °C. Most importantly, the HRP@Fe3O4-NH2/hNFs demonstrated good potential efficiency for the biodegradation of methyl orange, phenol red, and methylene blue dyes. The HRP@Fe3O4-NH2/hNFs were used for a total of 8 cycles to degrade methyl orange, phenol red, and methylene blue, and degradation of around 81, 96, and 56% was obtained in 8 h, respectively. Overall, we believe that the HRP@Fe3O4-NH2/hNFs reported in this work can be potentially used in various industrial and environmental applications, particularly for the biodegradation of recalcitrant compounds, such as textile dyes.

Synthesis and characterization of peanut shell-derived ferromagnetic activated carbon: application in the Fenton process for the degradation of methyl orange

The objective of the current work was to synthesize and characterize ferromagnetic activated carbon from peanut shells (PSs) and apply it for the degradation of methyl orange (MO) following the heterogeneous Fenton process. PSs were activated with phosphoric acid and potassium hydroxide at 1:1, 1:2, and 1:3 solid/liquid activation ratios and different concentrations (0.5, 1, and 1.5 M) and pyrolized at 500°C. Based on the iodine indexes, KOH-activated carbon adsorbents exhibited higher porosity than the H3PO4-activated adsorbents. KOH-activated carbon at a 1:3 activation ratio (iodine value 591 mg/g) was selected for magnetization using iron (II) ions and catalytic mineralization of MO dye. The ferromagnetic activated carbon (AC-PS@FeII) was characterized using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) analysis, and nitrogen-adsorption BET measurements. AC-PS@FeII contained ferromagnetite with a cubic spinel structure and a specific area of 181.96 m2·g–1. AC-PS@FeII degraded MO with a degradation efficiency of 99.22% at pH 2, 4 g/L of catalyst dosage, and a 50-min contact time. The results of recyclability tests, using distilled water, revealed a slight decrease in degradation capacity after four runs, indicating that the developed catalyst was appreciably stable. The hetero-Fenton catalyst from peanut shells could be an ideal catalyst for treating wastewater contaminated with dyes as a path toward a circular economy.