Methyl Orange Dye Research Articles

Silver Sulfide Anchored Anatase TiO2 Nanoparticles for Ultrafast Degradation of Selective Textile Dyes

AbstractThe surface modification of the TiO2 with selective narrow band gap of metal or metal sulfide is an attractive attention in recent years. Herein, tiny Ag2S nanoparticles are well anchored on the TiO2 surface by a cost‐effective chemical precipitation method for efficient photocatalytic activity. The decoration of Ag2S nanoparticles is clearly identified through electron microscopy studies. The UV‐Vis diffuse reflection spectra (DRS) revealed that TiO2/Ag2S composites absorbed broad spectrum in the visible region. The reduced band‐gap of 2.41 eV by anchored the Ag2S on TiO2 may boosted the photocatalytic activity. Particularly, incorporation of Ag2S nanoparticles increased charge separation efficiency, lowering recombination, and improving photocatalytic performance. Because of their unique structural and optical properties, TiO2/Ag2S composites have increased photocatalytic activity. The photocatalytic performance of the pristine Ag2S and Ag2S anchored TiO2 are Crystal violet (CV) and Methyl orange (MO) dye molecules under same experimental condition. As expected, the TiO2/Ag2S showed highest photocatalytic degradation efficiency than alone TiO2.

Removal of Anionic Methyl Orange Dye from Water by Poly[2-methyl-1H-indole] Derivatives: Investigation of Kinetics and Isotherms of Adsorption.

The adsorption properties toward methyl orange (MO) were evaluated for poly[2-methyl-1H-indole] and its derivatives. The influence of pH, ionic strength of solution, composition, and amount of sorbent on the adsorption of MO dye was investigated; the kinetics of dye adsorption was studied. The adsorption isotherms were analyzed using different models of sorption equilibrium. The presence of chemical interaction between polyindoles and dye was proved by IR and UV spectroscopy methods. The sorption of MO with polymers is realized mainly due to the formation of electrostatic interactions between the sulfogroup of the dye and the imino group of the sorbent. Microphotographs demonstrate the change in the morphology of polyindoles after adsorption, which further confirms the structural changes in the polymers. It was found that the main factors affecting the sorption capacity of the studied materials are the position and nature of substituents in the polymers and the sorption conditions. For example, polyindoles containing a methoxy group in their structure (o-OMePIn and m-OMePIn) have the best sorption activity. These polymers are effective in adsorbing dyes, which means that they can be used in wastewater treatment.

Correction to: Nonlinear Optical Refraction and Absorption Features of Methyl Orange Dye in Polar Solvents

Correction to: Nonlinear Optical Refraction and Absorption Features of Methyl Orange Dye in Polar Solvents

Fabrication of nanocomposite of graphene oxide/bentonite and evaluation its adsorption performances towards methyl orange and methylene blue from aqueous solution

Graphene oxide/bentonite (GO/B) nano composite was used as an adsorbent in the elimination of methyl orange and methylene blue dyes from water. Graphene oxide was synthesized via Hummers’ process and doped with bentonite clay. The obtained adsorbent was identified by FTIR, XRD, TGA, TEM and BET surface area. Some parameters such as solution pH, amount of the adsorbent, contact time, the original concentration of the dye and the operating temperature have been studied. The pathway of adsorption was adequately described kinetically and isothermally. The highest capacity of single layer adsorption of MO and MB was estimated to be 18.69 and 19.84 mgg-1, respectively. ΔG°, ΔH° and ΔS° estimations confirmed the physisorption process with exothermic and spontaneous nature. Moreover, GO/B’s recyclability was promising for using around three runs of adsorption with efficiency above 90 %. Finally, the usage of 50 mg of GO/B to remove MO and MB (50 mg.L-1) from industrial real specimens showed 95 and 93% recovery and 16.73-74.25% removal efficiency towards different metal ions. The preliminary findings suggested that GO/B could actually remove cationic and anionic dyes from solutions.

Brilliant green decolorization by dye decolorizing peroxidase producing bacterium, Achromobacter insolitus isolated from Forest soils of Similipal Biosphere Reserve, Odisha

Dye-decolorizing peroxidases (DyPs) are recently identified superfamily of heme-containing peroxidases which has received much attention for its potential application in dye decolourization. In the current research, six bacterial colonies (SDB1-6) showing lignolytic activity were isolated from forest soils of SBR using a minimal salt medium supplemented with alkali lignin and screened for DyP activity using brilliant green dye supplemented luria bertani agar medium. The highest DyP activity showing bacterium was identified using biochemical and 16SrRNA sequencing and was identified as Achromobacter insolitus. A. insolitus was found to be an efficient strain showing the highest DyP activity of 2.7 U/mL/ml at un-optimized condition. The RSM optimization was conducted to increase the DyP enzyme activity. A. insolitus demonstrated DyP activity of 6.20 U/mL/min with an increase of 2.29 times of enzyme activity in optimal condition of pH 7.0, temperature 25 °C, H2O2 concentration 0.1 mM, and time 24 h. The bacterium was further screened for dye decolorization taking crystal violet, methyl orange, methylene blue, brilliant green and methyl red dyes supplemented in LB medium. The bacterium showed maximum brilliant green degradation ability was analyzed using UV-Vis and FTIR analyses to characterize the degraded product. The highest brilliant green degradation activity of the A. insolitus in the present study could be exploited for bioremediation of brilliant green contaminated industrial effluents in a ecofriendly and cost effective way.

Terminalia bellirica (Gaertn.) Roxb. extract-mediated green synthesis of magnesium oxide nanoparticles for multifunctional applications

Green synthesis has emerged as a pivotal facet of nanotechnology, garnering significant attention for its inherent safety and eco-friendly attributes. This study presents a novel approach utilizing phytochemicals derived from Terminalia bellirica (Gaertn.) Roxb. fruit extract for the environmentally benign synthesis of magnesium oxide (MgO) nanoparticles. The resultant MgO nanoparticles were comprehensively characterized using UV–visible spectroscopy, X-ray Diffractometer (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Energy dispersive X-ray (EDX), and High-Resolution-Transmission Electron Microscope (HR-TEM). The synthesized MgO nanoparticles exhibited remarkable stability, evidenced by zeta potential of −8.84 mV and an average size of 73.41 nm. In an eco-physiological context, the application of MgO nanoparticles at a concentration of 5 mg/100 ml significantly enhanced shoot length (7.94±0.70 cm), root length (8.44±0.53 cm), moisture content (97.16±0.83%), and chlorophyll expression (18.34±0.99 mg/g fresh weight (FW)) in Trigonella foenum-graecum seedlings. Furthermore, the MgO nanoparticles demonstrated biocompatibility with soil bacteria and exhibited potent photocatalytic activity, achieving a 42% degradation efficiency of the organic dye methyl orange under UV irradiation for 60 minutes. In the realm of biomedical applications, MgO nanoparticles displayed dose-dependent cytotoxicity against human breast cancer cells (MCF-7), with an IC50 value of 37.39±0.05 µg/ml. Remarkably, MgO nanoparticles were also harnessed for their memcapacitive properties, showcasing excellent non-volatile memory characteristics, including endurance for 15,000 cycles and retention for 4000 seconds. In summary, this study underscores the multifunctional prowess of MgO nanoparticles synthesized through Terminalia bellirica fruit extract, spanning applications in plant physiology, environmental remediation, cancer therapeutics, and nanoelectronics. The environmentally conscious synthesis approach and diverse functionalities presented herein position these nanoparticles as future promising candidates for sustainable and versatile technological advancements.

Structural simulation and performance evaluation of a novel synthesized ZIF in the adsorption of MO from aqueous solutions.

Zeolitic imidazolate frameworks (ZIFs) are desirable materials widely applied as adsorbent for wastewater treatment. This study synthesizes and applies a novel structured ZIF with organic ligand of 2-methyl imidazole and metal salt of copper (II) sulfate as adsorbent. Its morphology and structure were investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, field emission scanning electron microscope, energy dispersive X-ray spectrometry, and mapping analysis. After structural analysis, the adsorbent structure was simulated and determined using Avogadro and Gaussian software. The removal efficiency of prepared ZIF in the removal of methyl orange from aqueous solution was evaluated. The effect of pH, the concentration of the dye in solution, dosage of the adsorbent, and the contact time between adsorbent and solution on the methyl orange removal were examined using central composite design of response surface methodology in five levels. The maximum dye removal of 99% was obtained for 2g adsorbent/L, pH of 3.3, and initial dye concentration of 121mg/L after 127min contact time. In addition, to reduce the economic costs and energy consumption, the synthesis time was also reduced and used to show the applicability of the adsorbent prepared and understand its advantages and disadvantages in removing methyl orange dye from aqueous solutions. This molecular adsorbent is stable, and it can be stored for months. On the other hand, this ZIF can be easily recovered and reused many times. In this research, after five times of recovery, there was no significant change in the effectiveness of the adsorbent.

EDTA-interlayer modified Mg/Fe layered double hydroxides for enhanced adsorption of methyl orange: Adsorption performance and mechanism study

Herein, we explored the efficacy of ethylenediaminetetraacetic acid (EDTA) intercalation modified layered double hydroxides (LDHs) composites for removing the anionic dye methyl orange (MO) from aqueous solutions. EDTA intercalated layered hydroxides (EDTA-Mg/Fe LDHs) with a 4:1 Mg/Fe molar ratio have been successfully prepared and thoroughly characterized using SEM-EDS, FTIR, XRD, XPS, UV-Vis and Zeta potential analysis. Batch adsorption experiments were conducted to evaluate the adsorption performance of the innovative adsorbent on MO. The results indicated successful EDTA loading into Mg/Fe LDHs, exhibiting excellent adsorption performance for MO. At pH 6.0, with a 0.03 g adsorbent dose, MO removal exceeded 91.10% within 90 min, following a pseudo second order kinetic model. The maximum adsorption capacity reached 1207.43 mg/g, fitting well with the Redlich Peterson model. Thermodynamic parameters suggested a spontaneous and favorable adsorption process. Furthermore, we assessed the desorption and regeneration effectiveness of EDTA-Mg/Fe LDHs, emphasizing the importance of developing cost-effective and environmentally friendly adsorbents with practical applications and scientific significance.

Degradation of methyl orange dye using Fe3O4/GO photocatalyst with iron derived from coastal Glagah Kulon Progo ore

Water pollution by dyes is still a serious problem that needs to be solved. This study offers a solution to degrade methyl orange dye using a photocatalyst material, namely Fe3O4/GO nanocomposite. Magnetite (Fe3O4) was synthesized from iron sand from Glagah Kulon Progo beach, using the coprecipitation method. Graphene oxide (GO) was synthesized by Hummers’ method, while the manufacture of the Fe3O4/GO nanocomposite was done by sonication method. The resulting magnetite, graphene oxide and nanocomposite were then characterized by XRD, UV–Vis and SEM-EDX. The effect of nanocomposite mass variation and irradiation time on the percentage degradation of the synthetic dye methyl orange (MO) in wastewater was investigated. The results of UV-Vis’s characterization showed that the best results were obtained when MO dye was degraded using 0.175 g nanocomposite in 40 mL of wastewater containing 10 ppm MO. The degradation of MO dye reached 99.05% under UV light irradiation for 240 minutes. Then investigated reuse of the nanocomposite was evaluated for three cycles, with the results showing an average efficiency decrease of 5.30%. This research contributes to the development of sustainable and effective photocatalytic materials for the treatment of dye-polluted water, especially MO.

Synthesis of geopolymer powder and beads based on red clay waste for the adsorption of methyl orange dye from aqueous solutions: Characterization, application of response surface methodology, and cost analysis

The current research focuses on the valorization of red clay waste (RCW) to develop alumino-silicate geopolymer binders (GPP) and geopolymer spheres obtained from GPP powder modified with sodium alginate (Alg/GPP). GPP and Alg/GPP were applied in the environmental field for the retention of methyl orange (MO) from an aqueous solution. The raw material and the synthesized geopolymers were characterized by various physico-chemical methods. The results of XRF, XRD, and FTIR confirmed the successful synthesis of GPP and Alg/GPP, while the SEM/EDX findings revealed the homogeneous surface of the adsorbents. A significant specific surface area was detected for GPP (73.56 m2/g) and Alg/GPP (91.24 m2/g) with a high cation exchange capacity around 122 meq/100g for GPP and 185 meq/100g for Alg/GPP. The removal process was performed using the response surface methodology according to the Box-Behnken design, optimizing the retention efficiency of MO by different factors, including temperature, initial concentration, solution pH, and contact time. The obtained data was treated through the analysis of variance (ANOVA) and fitted by a quadratic polynomial model based on multiple regression analysis. In an acidic medium at 45 °C, the optimal conditions for MO retention were estimated to be 120 mg/L of MO concentration in 55 min using GPP and 180 mg/L of MO concentration in 20 min using Alg/GPP. The pseudo-second-order kinetics were more appropriate for describing the MO removal onto GPP and Alg/GPP adsorbents. The Langmuir model identified a high retention capacity of MO around 94.78 mg/g via GPP and 224.85 mg/g via Alg/GPP. The thermodynamic data confirmed that the elimination of MO dye onto GPP and Alg/GPP adsorbents was endothermic, favorable, and spontaneous. This study provided insights into the valorization of composite materials based on solid waste in dye retention, which can potentially be employed in wastewater treatment.

Synthesis and Characterization of a Photocatalytic Material from TiO2 Nanoparticles Supported on Zeolite Obtained from Ignimbrite Residue Used in Decolorization of Methyl Orange

In the present work, a TiO2/zeolite photocatalyst was synthesized by dispersing TiO2 nanoparticles obtained through the sol-gel method onto the surface of natural zeolite derived from ignimbrite residue. The zeolite was obtained from an ignimbrite rubble treatment collected from a quarry in Arequipa City, Peru. The research focused on the effect of zeolite on the TiO2 nanoparticles. The synthesized photocatalysts were characterized using various techniques, including field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDS), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller surface area analysis (BET). The results revealed that the TiO2/zeolite samples displayed high crystallinity, with TiO2 being present in three phases and zeolite being present in the analcime phase. Furthermore, these samples exhibited a band gap of 3.14 eV and a high surface area compared to that of bare TiO2. Finally, the photocatalytic activity of the TiO2/zeolite composite obtained was evaluated toward the decomposition of 10 ppm and 20 ppm of methyl orange (MO) dye. The TiO2/zeolite samples demonstrated improved photocatalytic activity compared to that of pristine TiO2 under the same experimental conditions. This enhancement is primarily attributed to the increased specific surface area of the TiO2/zeolite samples, making them promising materials for future efficient and sustainable photocatalytic applications.

Investigating adsorption behaviour of methyl orange dye onto nano MgAl layered double hydroxide using Box-Behnken Design model

Investigating adsorption behaviour of methyl orange dye onto nano MgAl layered double hydroxide using Box-Behnken Design model

Antifouling polyphenylene sulfone tight-ultrafiltration membrane by co-depositing dopamine and zwitterionic polymer for efficient dye/salt separation

The exceptional hydrophilicity and charge equilibrium of zwitterionic polymers render them highly desirable as antifouling materials. In this study, a novel zwitterionic copolymer Poly(2-aminoethyl methacrylate-Ethyl acrylatesulfopropyl piperidine salt) [P(AE-EA)] was successfully synthesized. Subsequently, a novel tight-ultrafiltration (t-UF) antifouling membrane employed for dye/salt separation was fabricated by co-depositing dopamine (DA) and P(AE-EA) onto the polyphenylene sulfone (PPSU) membrane substrate. The polydopamine (PDA) and P(AE-EA) are covalently linked through the formation of a covalent bond via Michael addition and Schiff base reactions. By regulating the ratio of PDA and P(AE-EA), the optimized membrane shows a denser and hydrophilic selective layer. The composition and characteristics of the membrane are investigated by serial characterization. The electrostatic adsorption between the membrane surface and the pollutant can be effectively weakened by the incorporation of a zwitterionic polymer P(AE-EA) with neutral charged and hydrophilicity. The modified membrane demonstrates exceptional antifouling performance for BSA, high rejection towards both negatively and positively charged dyes (Congo red, Methylene blue, Methyl orange and Rhodamine B), as well as efficient salt permeance for NaCl, Na2SO4, MgCl2, Mg2SO4 in comparison to that of the pure PPSU membrane. The results presented herein demonstrate the remarkable potential of the novel zwitterionic t-UF membrane for effectively separating dye/salt mixture solutions in the textile industry.

Greener approach for the synthesis of Ag decorated ZnO–CeO2 nanostructure using Moringa oleifera LE and its investigation as photocatalyst for degradation of ciprofloxacin and methylene orange

Green synthesis of silver decorated ZnO–CeO2 nanostructure (Ag@ZnO–CeO2 NS) mediated Moringa oleifera LE and its photocatalytic potential against ciprofloxacin antibiotic and Methylene orange dye under sunlight. The synthesized ZnO–CeO2 and Ag@ZnO–CeO2 NS were characterized using X-ray diffraction (XRD) analysis. The crystallite size and crystallinity were calculated to 74 nm and 89% respectively using XRD analysis. X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Ag, Zn, Ce and oxygen vacancies in green synthesized Ag@ZnO–CeO2 NS. Also, PL spectroscopy analysis showed the oxygen vacancies due to defects in nanostructure. The bandgap of prepared nanostructure was calculated to 2.0 eV by UV–visible spectroscopy analysis. Ag@ZnO–CeO2 NS average particles size was evaluated to 40 nm by scanning electron microscopy (SEM) analysis and energy-dispersive X-ray (EDX) analysis confirmed the presence of Ag, Zn and Ce in nanostructure. The Ag@ZnO–CeO2 NS showed an excellent Brunauer-Emmett-Teller (BET) surface area of 165 m2g-1 and 15 nm of pore diameter. Moreover, Fourier transform infrared (FTIR) spectroscopy was used to analyze chemical bonding and interaction and RAMAN spectroscopy confirmed the presence of oxygen vacancies. The thermal decomposition and heat flow was accessed by thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) The Ag@ZnO–CeO2 NS demonstrated great potential for environmental remediation which offered effective approach for the removal of Ciprofloxacin antibiotic and Methylene orange dye from wastewater with 74% and 85% photocatalytic activity respectively. The stability of catalyst after 5 cycles of reusability was evaluated by XRD analysis which showed the crystalline structure. This research contributes to the development of advanced nanomaterials with improved photocatalytic properties and the removal of emerging contaminants.

S-Schematic CuWO4/ZnO nanocomposite boosted photocatalytic degradation of organic dye pollutants

S-schematic CuWO4/ZnO nanocomposite photocatalyst was synthesized by an impregnation method. Synthesized CuWO4 and ZnO nanoparticles, and CuWO4/ZnO nanocomposites were thoroughly characterized. X-ray diffraction (XRD) analysis of the CuWO4/ZnO nanocomposite confirmed the respective triclinic and hexagonal wurtzite structures of CuWO4 and ZnO crystals. Raman and Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS) revealed bond formations in CuWO4 and ZnO, and confirmed the synthesis of the CuWO4/ZnO nanocomposite. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed CuWO4 nanoparticles adhered to ZnO aggregates. Energy dispersive X-ray spectrometry (EDS) confirmed the distribution of CuWO4 on the ZnO aggregates. UV–Vis diffuse reflectance spectroscopy (DRS) showed optical bandgap energies of 2.36 eV for CuWO4 and 3.18 eV for ZnO nanoparticles. The photocatalytic performance of the CuWO4/ZnO nanocomposite was investigated through the degradation of the cationic dyes methylene blue (MB) and Rhodamine B (RhB) and the anionic dye methyl orange (MO). A 5.0%CuWO4/ZnO nanocomposite degraded 100% of MB within 120 min, 91.02% of RhB within 300 min, and 89.13% of MO within 300 min. The pseudo-first order kinetic rate constant fit well for the degradation of all the dyes on the CuWO4/ZnO nanocomposite. The CuWO4/ZnO nanocomposite could better degrade the cationic dyes than the anionic dye in an aqueous solution. The hole (h+), the hydroxyl radical (•OH), and the superoxide ion (•O2−) were the active species responsible for degrading MB, RhB and MO dyes. The proposed CuWO4/ZnO nanocomposite could be applied for environment friendly wastewater treatment.

Strategies for Effective Degradation of Methyl Orange Dye in Aqueous Solution via Electrochemical Treatment with Copper/Graphite Electrodes

This study investigated the electrochemical degradation of methyl orange dye (MO) in aqueous solution using copper/graphite electrodes as anode and cathode respectively. The process parameters such as electrolyte concentrations, current density, pH and temperature were analyzed. The results proved that copper/graphite electrodes were effective for MO degradation and the reaction followed the first-order kinetic model. The degradation efficiency decreased with increasing MO concentration and increased steadily with current density. The pH trend with degradation efficiency was pH 9 (98%) > pH 7 (96%) > pH 3 (77%) after 70 min of electrolysis time, which shows that the alkaline conditions favoured the degradation process. Fourier transform infrared spectroscopy (FTIR) and UV–Vis absorption spectroscopy confirmed the dye degradation process, with the formation of degradation intermediates. The FTIR results revealed that the oxidative degradation of MO may be initiated at the N=N azo bond, which was confirmed by quantum chemical modelling of the electronic structure parameters of MO.

Synthesis and characterization of MOF polymer nanocomposites for Chromium adsorption and their antimicrobial properties

This study describes the preparation of MOF and its polymer composites, namely Co@BTC(MOF1), Co@BTC(PAA)(MOF2), and Co@BTC(PAA)(CTAB)(MOF3), by assimilating cobalt nitrate hexahydrate [(CoNO3)2·6H2O] with trimesic acid, polyacrylic acid (PAA), and cetyltrimethylammonium bromide (CTAB) using a solvothermal procedure at 100℃ for 12 h. All MOF composites exhibited remarkable adsorption properties and thermal and chemical stability properties. These polymer composite MOFs are explored for the adsorption of anionic dyes such as Methyl Orange (MO) and Congo Red (CR), cationic dye Methylene Blue (MB), and Chromium (VI) from wastewater. A 90–95 % adsorption rate for MO and CR dyes was observed within 60 min using 100 mg of MOF composites. Within 60 min, the MOF composites achieved an adsorption rate of 90–95 % for MO and CR dyes when 100 mg of the composites were used. Furthermore, MOF2 and MOF3 have exhibited a remarkable 92 % efficiency in adsorbing Cr(VI) during one hour, following a pseudo-second-order kinetic model. The composites were examined for their anti-bacterial efficacy against Bacillus (Gram-positive), E. Coli (Gram-negative), and Saccharomyces cerevisiae. The results were compared to ciprofloxacin, a conventional antibiotic, using the agar diffusion method. MOF2 and MOF3 have demonstrated long-lasting and potent antimicrobial activity, successfully inhibiting the growth of bacteria for a period of at least 90 days. Furthermore, the polymer composites of MOFs exhibit notable capability in scavenging radicals, particularly against ascorbic acid, as determined by the DPPH method. The inhibition rates for the composites are 68.7 % and 65.9 %, respectively. This indicates that these polymer MOF composites possess potent anti-microbial activity, making them an ideal candidate for addressing the inhibition of bacterial growth.

A floating biosorbent of polylactide and carboxylated cellulose from biomass for effective removal of methylene blue from water

A floating adsorbent bead was prepared from polylactide (PLA) and maleic anhydride (MAH)-modified cellulose in a one-pot process (OP bead). Cellulose was extracted from waste lemongrass leaf (LGL) and modified with MAH in the presence of dimethylacetamide (DMAc). PLA was then added directly into the system to form sorbent beads by a phase separation process that reused unreacted MAH and DMAc as a pore former and a solvent, respectively. The chemical modification converted cellulose macrofibres (55.1 ± 31.5 μm) to microfibers (8.8 ± 1.5 μm) without the need for grinding. The OP beads exhibited more and larger surface pores and greater thermal stability than beads prepared conventionally. The OP beads also removed methylene blue (MB) more effectively, with a maximum adsorption capacity of 86.19 mg⋅g−1. The adsorption of MB on the OP bead fitted the pseudo-second order and the Langmuir isotherm models. The OP bead was reusable over five adsorption cycles, retaining 88 % of MB adsorption. In a mixed solution of MB and methyl orange (MO), the OP bead adsorbed 96 % of the cationic dye MB while repelling the anionic dye MO. The proposed method not only reduced time, energy and chemical consumption, but also enabled the fabrication of a green, effective and easy-to-use biosorbent.

Photocatalytic Degradation of Methylene Blue and Methyl Orange Dye by Using the Core-Shell Structure of Fe3O4@ZnS Nanoparticles

A straightforward and highly efficient method was developed for the synthesis of Fe3O4@ZnS core-shell nanoparticles (NPs). These synthesized materials were subsequently utilized for the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes. The structural characteristics of the prepared sample were meticulously investigated through X-ray diffraction (XRD) and field-effect scanning electron microscopy (FESEM). The XRD analysis confirmed the crystalline phase formation in the Fe3O4 nanoparticles, while a study in the Vibrating Sample Magnetometer (VSM) mode emphasized their strong ferromagnetic behavior. The degradation of dyes was comprehensively studied using UV-Vis analyses, taking into account factors such as pH and initial dye concentration in the decolorization process. The synthesized Fe3O4@ZnS core-shell nanostructure underwent thorough characterization using XRD, UV-Vis spectroscopy, SEM, Fourier-transform infrared spectroscopy (FT-IR), and VSM mode in PPMS. Furthermore, the reusability of the catalyst was explored, yielding promising results. The findings demonstrated the efficient photocatalytic degradation of MB and MO dyes under UV-visible irradiation, achieving significant results within 30-minute intervals.

Plasma electrolytic formation and characterization of MnWO4/WO3 film heterostructures

MnWO4/WO3 p-n heterojunction films were fabricated using a one-step method consisting of the plasma electrolytic oxidation (PEO) of titanium in homogeneous electrolytes containing paratungstate ions and stable water-soluble EDTA-chelated manganese. The influences of the formation current density and W:Mn molar ratio of the electrolyte, which was varied from 1:2 to 2:1, on the composition, morphology, and optical and photocatalytic properties of the resulting coatings were studied. X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray analysis, Raman spectroscopy, and ultraviolet diffuse reflectance spectroscopy were used to characterize the formed composites. Regardless of the W:Mn ratio of the electrolyte, the coatings contained crystalline t-WO3 and m-MnWO4. Depending on the formation conditions, the optical band gap energies of the composites varied from 2.63 to 3.01 eV. The largest absorption red shift and lowest band gap energy were observed in the film composite formed in an electrolyte with W:Mn = 2:1, at a current density of 0.2 A cm−2. Composites obtained in electrolytes with W:Mn ratios of 2:1 and 1:1 exhibited photocatalytic activity in the degradation of rhodamine C and methyl orange dyes in the presence of 10 mmol L–1 H2O2 under ultraviolet and visible light irradiation. The role of hydrogen peroxide in this dye degradation on PEO-coated composites under light irradiation is discussed.