Methylene Blue Concentration Research Articles

Surface decoration of Nb2O5 hollow fibers by graphene oxide for enhanced photocatalytic degradation of methylene blue

AbstractThis paper describes the fabrication of ceramic Nb2O5 hollow fibers covered by a thin graphene oxide (GO) layer using the vacuum‐assisted dip‐coating process for the efficient photocatalysis degradation of methylene blue (MB) under UVC light irradiation. Pristine and GO‐coated Nb2O5 hollow fibers were evaluated for photocatalytic degradation at different initial dye concentrations and pH values. A photodegradation of 66.4% of the dye molecules was achieved using the pristine Nb2O5 hollow fibers at 57.4 ± 0.1 mg mL1, initial MB concentration of 10 mg L−1, and pH of 11. Under the same experimental conditions, the GO‐coated Nb2O5 hollow fibers degraded 100% of the MB molecules. Additionally, the GO‐coated Nb2O5 hollow fibers were successfully reused for four reaction cycles and exhibited suitable long‐term stability. Thus, the proposed ceramic Nb2O5 hollow fibers with a surface decorated by a GO layer presented suitable characteristics for use as a photocatalyst in MB degradation.

Synergistic photocatalytic degradation of methylene blue using TiO2 composites with activated carbon and reduced graphene oxide: a kinetic and mechanistic study

This comprehensive study explored the removal of methylene blue (MB) from aqueous solutions as a model pollutant, utilizing solar-driven photocatalysis with nano-sized titanium dioxide (TiO2) and composites with activated carbon (AC) and reduced graphene oxide (RGO). This research introduces continuous solar reactor instead of conventional batch experiments investigating its design configuration. Utilizing response surface methodology (RSM), the study determined the optimal process conditions (MB concentration at 30 mg/L, pH 8.82, irradiation time 138 min), under which TiO2 achieved a 93.13% MB removal efficiency. The study further revealed that the integration of TiO2 with AC and RGO (5% wt.) significantly enhanced the MB photocatalytic degradation. The TiO2/AC composite achieved 98.3% MB degradation in 138 min of solar exposure, related to its large specific surface area of 146 m2/g and a pore volume of 0.439 cm3/g. Likewise, the TiO2/RGO composite demonstrated 97% removal with a surface area of 102 m2/g and a pore volume of 0.476 cm3/g, significantly better than nano-TiO2. Additionally, the research investigated the role of the solar reactor configuration on MB removal. Using 26 mm Pyrex tube diameter with 15 cm long on parabolic aluminum concentrator inclined at 30° optimally achieved the peak MB degradation efficiency. Recyclability tests shown a noticeable decrease in nano-TiO2 efficiency to 56.03% without regeneration; however, after regeneration following the third cycle, the efficiency significantly recovered to 70.07%. Thereby, this paper introduces an innovative, continuous, and well-designed solar reactor system for dye removal, employing nano-TiO2 and its composites with AC and RGO for improved photocatalytic efficiency under statistically optimized process conditions.

Coupling adsorption and in-situ Fenton-like oxidation by iron-containing low-grade attapulgite clay towards organic pollutant removal: From batch experiment to continuous operation

Coupling adsorption and in-situ Fenton-like oxidation process was developed for Methylene blue (MB) using refined iron-containing low-grade attapulgite (ATP) clay, and the removal mechanism was investigated. The MB was initially adsorbed on the porous ATPs, and then the enriched MB was removed by the H2O2-assisted Fenton-like oxidation with the iron-containing ATP catalyst. Under optimal conditions, the ATP powder exhibits the maximum removal efficiency of 100% with negligible iron leaching (1.5 mg L-1) and no sludge formation. Furthermore, polysulfone/ATP (PSF/ATP) pellets were fabricated through a water-induced phase separation process to construct a fixed-bed reactor (FBR) for continuous contaminant removal. For the first cycle, the maximum adsorption capacity was 15.5 L with an outlet MB concentration of 1.973 mg L-1 (˂ 2 mg L-1, GB4287-2012) using the PSF/ATP pellets containing 50.0 g of ATP powders, and the maximum Fenton-like oxidation capacity was 35.5 L with the outlet concentration of 0.831 mg L-1. After five cycles, the total treated volume of the MB solution was ca. 255 L, and the efficiency remained above 99%. After 10 hours of continuous treatment towards practical resin industrial wastewater, the chemical oxygen demand (COD) removal efficiency was still measured at 83.05%, costing 0.398 $ m-3. These results demonstrate the practical applicability of iron-containing low-grade ATP clay for textile water treatment.

Application of sewage sludge derived hydrochar as an adsorbent for removal of methylene blue

Hydrothermal pretreatment (HTP) is used to convert biomass into hydrochar (HC) through the application of heat and pressure in a water-based medium. The HC has emerged as a promising material for various environmental applications including wastewater treatment, soil amendment, and carbon sequestration. In this study, the applicability of sewage sludge (SS) derived HC was tested as an adsorbent for methylene blue (MB) dye removal from wastewater. The HC was also subjected to chemical activation with KOH before the adsorption study. The HC samples were characterized for structural morphology and molecular functionalities using instrumental analysis. All the HC samples exhibited almost similar adsorption capacity (∼190 mg/g) for MB after 24 h of contact time (MB concentration = 200 mg/L, solution pH = 7 and adsorbent dose = 1 g/L). The equilibrium data could be adequately fit in Langmuir model equation. The negative value of free energy indicated favorable MB adsorption process. The study demonstrated that the SS derived HC can be recycled as adsorbent in wastewater treatment plant which is not only an environment-friendly approach but also may reduce cost of tertiary treatment at sewage treatment plant often required to remove emerging contaminants.

Methylene Blue Degradation Using Non-Thermal Plasma

Methylene blue (C16H18ClN3) dye can be decomposed using non-thermal plasma. However, there is a problem in that the maintenance of electrodes and dielectrics is necessary due to the durability and heat generation problems due to the high temperatures. Therefore, in this study, a comparative experiment was performed between the flat DBD plasma module and the diffuser DBD module under the same conditions. For methylene blue decomposition, the characteristic changes in the air flow rate, ozone production rate, energy consumption rate, and decomposition rate were compared. In the experiment, 7 L water was placed in a 15 L reactor, and measurements were performed for approximately 1 h. We performed the same process by setting the initial methylene blue concentration to 143 mg/L. According to the results, the flat DBD module achieved a decomposition rate of 100% in 40 min, an energy yield of 46.7 g/kWh, and an ozone generation amount of 6.5 g/h. The diffuser DBD module achieved a decomposition rate of 90%, an energy production of 24.6 g/kWh, and an ozone generation of 1.97 g/h in 60 min.

Biosorption of methylene blue by bone meal: experimental and modeling with machine learning and full factorial design

Sorption technologies have been proposed for the treatment of water containing methylene blue (MB), a toxic and persistent pollutant. Despite its environmental risks, the role of process variables in MB removal has not been fully explored through experimental design. The objective of this study is to assess the potential of bone meal powder (BMP), an underexplored agricultural byproduct, as an affordable adsorbent for the removal of MB from water. BMP was subjected to a series of analytical characterization techniques, and its adsorption capacity was evaluated through a comprehensive factorial design, which investigated the effects of biosorbent dosage, solution pH, and initial MB concentration. The study revealed that the highest adsorption level was 14.49 mg g−1, attained under the following conditions: 1 g L−1 BMP, pH 11, and 100 mg L−1 MB. The adsorption equilibrium was reached within 60 min, with a measured capacity (qexp) of 18 mg g−1. Theoretical adsorption isotherms indicated a capacity of 63 mg g−1, which aligned well with the Langmuir model. To predict adsorption outcomes, machine learning models were applied, with multiple linear regression performing best. Optimization of decision trees and neural networks improved accuracy but risked overfitting. FT-IR, XRD, and ICP analyses indicated ion exchange as a significant mechanism of adsorption. In desorption studies, H2SO4 was the most effective agent, achieving 68.72% desorption efficiency. BMP exhibited optimal recyclability for up to four cycles before efficiency declined.

Optimization of methylene blue photodegradation by Cr-PTC[sbnd]HIna/TiO2 composite using box-behnken design application

The Cr-PTCHIna/TiO2 composite synthesized using an isonicotinic acid modulated chromium and perylene-based metal-organic framework (Cr-PTCHIna MOF) and titanium oxide (TiO2) showed promising results for the photodegradation of methylene blue. The composite was synthesized through the solvothermal method with a molar ratio of Cr and Ti of 1:1 mmol. The XRD diffraction patterns of Cr-PTCHIna/TiO2 composite showed sharp peaks at 2θ = 12°, 25°, 27°, 37°, 48°, 54°, 55°, and 62° with crystal sizes of 14.144 nm. The Cr-PTCHIna/TiO2 composite has a band gap energy of 2.02 eV and a rod-shaped morphology with a particle size of 239.16 nm. The Box-Behnken Design (BBD) demonstrated that the composite can achieve an optimum degradation efficiency of methylene blue of 88.55 % under methylene blue initial concentration of 35.7 ppm, pH 6.6, and photocatalyst mass of 0.13 % under 250-watt Mercury lamp irradiation for 2 h.

3D Printed Metal Organic Framework Hydrogel for Dye Adsorption and Gas Sensing

AbstractMetal organic frameworks (MOFs) have tunable chemical structures, orderly pore structures, and modifiable surface functional groups making them a promising material for environmental remediation. However, their rigid powder morphology poses significant challenges for customizing MOF structures with adjustable mechanical properties. Here, we synthesis the stretchable UV‐curable MOF hydrogels through high‐resolution digital light processing 3D printing, and evaluated its adsorption effect on seven common dyesand.The results showed that it had selective adsorption effect on methylene blue (MB), and the adsorption effect increased with the increase of the initial concentration of MB: its adsorption capacity on 6 mgL−1, 12 mgL−1 and 24 mgL−1 MB solution reached 13.55 mgg−1, 26.31 mgg−1 and 50.70 mgg−1 respectively. Compared to powdered MOFs, the 3D‐printed MOF (Cu‐BTC) exhibited superior adsorption for dye and radioactive pollution, with methylene blue adsorption increasing from 8.93 mgg−1 to 25.05 mgg−1 and I2 adsorption from 141.56 mgg−1 to 792.65 mgg−1. Furthermore, the 3D‐printed MOF structure proved easily cleanable with dilute HCl and reusable over five times without degradation. In addition, our study highlighted the suitability of the 3D‐printed MOF for CO2‐sensing devices, demonstrating its broad applicability in environmental remediation and sensing technology.

One-pot construction of α-Fe2O3/ZnNiFe2O4 heterojunction by incomplete sol/gel-self-propagating method with choline chloride-ethylene glycol media and its photo-degradation performance

A magnetic α-Fe2O3/ZnNiFe2O4 composite photocatalyst was synthesized through a one-pot reaction employing choline chloride-ethylene glycol deep eutectic solvents and an incomplete sol-gel self-propagating method. The photocatalytic performance was assessed by removing methylene blue (MB) under 40 W visible light. With a 1.0 g/L catalyst dosage, 10 mg/L MB concentration, and pH levels of 6 and 12, removal rates of 97 % and 99 % were achieved within 90 min, respectively. The composite also demonstrated effective degradation of methyl orange (MO) and malachite green (MG). Stability tests revealed minimal reduction in photocatalytic activity after four cycles. Active species analysis identified ·O2⁻ and ·OH as the primary agents in the photocatalytic process. XRD, XPS, UV–VIS DRS, HRTEM, PL, and EIS analyses confirmed the formation of a Z-scheme heterojunction between ZnNiFe2O4 and α-Fe2O3, which enhanced the specific surface area, electron transport capacity, and narrowed the band gap. This heterojunction improved the separation efficiency of photogenerated electron-hole pairs, resulting in enhanced photocatalytic activity and stability. This study presents a novel approach for preparing Z-scheme heterojunction photocatalysts through a one-pot reaction.

Novel Efficient and Eco‐Friendly Biosorbent Derived from Ditax (Detarium senegalense) Fruit Hulls for Removal of Cationic Dyes: Adsorption Modeling and Statistical Optimization

AbstractRemediation of wastewater laden with dyes using optimized and less expensive techniques remains a challenge for environmental protection. In the current research work, alkaline activation approach was employed to derive a biosorbent from ditax fruit hulls (DS‐FHB), and its sorption performance was tested on Methylene blue (MB) dye biosorption with optimizing adsorption parameters. Structural and chemical properties of DS‐FHB including crystallinity, morphology, and surface functionality were analysed using XRD, SEM, FTIR technics, and pHPZC determination. Optimization of adsorption parameters using a centered composite design (CCD) from response surface methodology led to achieving a peak dye removal rate of 98.97 %. The optimal conditions were determined as DS‐FHB mass of 0.23 g, pH 7.12, contact time 39.00 min, and initial MB concentration of 69.35 mg/L. The findings demonstrated a strong alignment with both the Langmuir isotherm and pseudo‐second order kinetic model, suggesting their appropriateness in describing the adsorption process of MB onto DS‐FHB. According to the Langmuir isotherm model, the sorption of MB dye onto DS‐FHB occurred by monolayer formation with a maximum dye sorption capacity of 96.453 mg/g. Based on the structural and physico‐chemical properties of DS‐FHB biosorbent, and its adsoption applicability evaluated in the experimental conditions, detax derived‐biosorbent can be proposed as a successful and effective low‐cost biosorbent for removing cationic dyestuffs from aqueous solutions.

High-performance removal of methylene blue dye using porous lignin extracted from sugarcane bagasse by deep eutectic solvent

This study evaluated the ability of triethyl benzyl ammonium chloride/lactic acid deep eutectic solvent extracted lignin (TEBAC/LA-DES-L) to adsorb methylene blue (MB) without additional functional group modification. The structure and morphology of TEBAC/LA-DES-L were characterized using SEM, BET, FT-IR, and TGA techniques. Various factors influencing MB adsorption, such as extraction temperature, solution pH, adsorbent dose, initial MB concentration, adsorption time, and reaction temperature, were investigated. The Redlich-Peterson isotherm displayed a good fit for the experimental data, with a maximum adsorption capacity of 85.16 mg/g. Kinetic analysis suggested that the adsorption process followed the pseudo-second-order model, with adsorption occurring in <100 min on DES-L-4 h. The mechanism of MB adsorption on DES-L-4 h was attributed to electrostatic attraction, hydrophobic interactions, and hydrogen bonding forces. Overall, DES-L-4 h demonstrated high adsorption capacity and rapid adsorption rate, making it a promising adsorbent for effectively removing cationic dyes from wastewater.

Silica Gel From Bagasse Ash for Methylene Blue Adsorption

Most silica sources are from non-renewable natural sand or rock materials, which affect the element's diminishing availability in the environment. Because bagasse ash has a relatively high silica concentration, it can be used as a silica source to manufacture silica gel. HCl is added during the sol-gel process of silica gel synthesis. The silica gel's characterization employs FTIR, XRD, and SEM instruments. Characterization results showed that silica gel contains silanol groups identified by the appearance of vibrations at the wavenumber of 3383,93 cm-1 and 1635,17 cm-1. Vibrations of the siloxane group appear at the wavenumber of 1020,83 cm-1 and 579,88 cm-1. Silica gel diffractogram showing dilated diffraction peaks at 2q = 22,90ᵒ. Silica gel has potential as an adsorbent in adsorbing methylene blue dye. The ideal parameters for the methylene blue adsorption process are pH 10 and 45 minutes of contact time., silica gel weight of 0.1 g, and methylene blue concentration of 100 mg/L. Using the Langmuir isotherm rule, the silica gel of bagasse ash has a high adsorption capacity of 56.818 mg/g.

Clinical aPDT's effect on Candida albicans: Antifungal susceptibility, virulence gene expression, and correlation with leukocyte and neutrophil counts

BackgroundOur previous clinical trial demonstrated that antimicrobial photodynamic therapy (aPDT) with methylene blue (MB) and potassium iodide (KI) effectively killed Candida albicans (C. albicans) in adult AIDS patients with oral candidiasis, regardless of biofilm formation or 25S rDNA genotype. This study evaluated changes in antifungal susceptibility and virulence gene expression in C. albicans before and after aPDT, and explored factors related to clinical aPDT efficacy. MethodsTwenty-one adult AIDS patients with C. albicans oral candidiasis were divided into Group a (400 μM MB, N = 11) and Group b (600 μM MB, N = 10). Both groups received two aPDT treatments, where MB was applied for 5 min, followed by 300 mM KI, and illuminated for 30 min (37.29 J/cm²). C. albicans isolates were collected before and after treatment to assess antifungal susceptibility (fluconazole, itraconazole, flucytosine, amphotericin B) and gene expression (CAT1, HWP1). Peripheral blood tests were analyzed for correlations with aPDT efficacy. ResultsaPDT reduced minimum inhibitory concentration (MIC) values for amphotericin B, fluconazole, and flucytosine, with significant reductions primarily after the first treatment. MIC reductions differed between groups, with Group a showing greater decreases in flucytosine and fluconazole MICs, and Group b in amphotericin B MICs. No significant changes in CAT1 or HWP1 expression were observed. Clinical efficacy of aPDT negatively correlated with leukocyte and neutrophil levels. ConclusionsaPDT effectively reduces MICs of antifungal drugs against C. albicans isolated from treated patients, particularly after the first treatment. The concentration of MB required to reduce MICs varies among different antifungal drugs. aPDT does not alter CAT1 or HWP1 expression, and its clinical efficacy in eradicating C. albicans is negatively associated with leukocyte and neutrophil levels.

Effective removal of different dyes using run-of-mine and processed coal samples

Coal, traditionally utilised solely for combustion, is now being investigated for its potential as an adsorbent in purifying drinking water by eliminating hazardous metal ions. Limited research exists regarding its effectiveness in reducing organic dye levels. Presented here are the outcomes of an extensive investigation into various carbon samples' efficacy as adsorbents for wastewater color removal. Samples of coal sourced from Western Coalfield Limited (WCL) were meticulously processed and characterized, encompassing run-of-mine coal and acid-leached coal. A comprehensive array of techniques, including scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, was employed for coal characterization. Proximate analysis and gross calorific value (GCV) were employed to assess coal's physical attributes. The adsorption behavior of methylene blue (MB) and crystal violet (CV) on coal was scrutinized, varying factors such as contact time, pH, initial MB and CV concentrations, and adsorbent doses. Optimal adsorption parameters for MB were determined as pH 2, initial concentration of 1 ppm, 0.2 g adsorbent dose, and 60 min contact time. For CV, optimal conditions were pH 8, initial concentration of 6 ppm, 0.4 g adsorbent dose, and 45 min contact time. MB adsorption kinetics favored the pseudo-second-order reaction model, with Freundlich isotherms providing a better fit than Langmuir isotherms. Conversely, CV adsorption kinetics favored the pseudo-second-order reaction model, with Langmuir isotherms exhibiting a superior fit compared to Freundlich isotherms.

Synergistic adsorption-photocatalytic degradation of methylene blue by Fe3O4/HKUST-1 composite modified with graphene oxide

Abstract Methylene blue (MB) is the most commonly used cationic dye, but the complex structure of MB makes it harder to be removed from the wastewater by conventional techniques. The integration of adsorption and photocatalytic has been proposed to overcome the drawbacks of the sole technology for more efficient and eco-friendly removal. A magnetic MOF composite, Fe3O4/HKUST-1, was successfully synthesized using the solvothermal method. The addition of graphene oxide (GO) uses the in situ method. XRD and FTIR results revealed the presence of GO, which was dispersed into the composite. SEM images for the composite showed GO(20)/Fe3O4/HKUST-1 was octahedral with Fe3O4 and GO distributed on the surface and between HKUST-1. When the initial concentration of MB was 50 mg/L, the composites exhibited high MB removal efficiency (92,75%) under irradiation through the combination of adsorption-photocatalytic. The effective removal of Fe3O4/HKUST-1 combined with the photocatalyst properties of GO, makes the composite highly efficient for applications in water purification. The adsorption kinetics of MB on the GO(20)/Fe3O4/HKUST-1 were well-fitted with the pseudo-second-order kinetic model.

Adsorption parameters optimization of spent coffee ground biochar for methylene blue removal using response surface methodology

This study investigates the potential of spent coffee ground biochar (SCGB) as a sustainable and cost-effective adsorbent for the removal of methylene blue (MB), a hazardous dye commonly used in the textile and printing industries. A response surface methodology (RSM) approach with central composite design (CCD) was employed to systematically investigate the effects of key process parameters, including adsorbent dosage, solution pH, contact time and temperature, on MB removal efficiency. The analysis revealed that adsorbent dosage and temperature as critical factors influencing MB removal, with a linear model providing a strong correlation. Optimal conditions for MB removal were determined to be 0.99 g of SCGB, 30 min of contact time, 30 °C temperature, and a solution pH of 7. Under these conditions, MB removal reached 99.99%, with a desirability of 1.000. The experimental results closely matched the predicted values, differing by only 0.02%, thus validating the accuracy of the model. Kinetic studies indicated a rapid adsorption process, well-described by both pseudo-first and pseudo-second order models. Isotherm analysis confirmed the applicability of the Freundlich model, suggesting favorable adsorption with increasing MB concentration. The high adsorption capacity of SCGB is attributed to its carbonaceous and porous structure, highlighting its potential as an effective adsorbent for dye removal in wastewater treatment applications.

Development of a Novel Adsorbent Derived from Olive Mill Solid Wastes for Enhanced Removal of Methylene Blue.

Industrial wastewater discharge, tainted with hazardous substances, including dyes like methylene blue (MB) from the textile sector, further emphasizes the need for water treatment to produce safe drinking water. This study explores the potential of olive mill solid waste, an abundant and cost-effective agricultural waste in Mediterranean regions, to yield high-quality activated carbon (AC) with zinc chloride activation for MB adsorption. The activation process, carried out at a modest temperature of 500 °C without the need for an inert atmosphere, resulted in AC with remarkable characteristics, boasting a substantial surface area of 1184 cm2·g-1 and a total pore volume of 0.824 cm3·g-1. Extensive characterization of the AC was carried out through a large range of surface techniques. The pH of the solution had minimal influence on MB adsorption, the maximum removal was 95%, which was under slightly acidic pH conditions (5.8), and the adsorbent dose was 0.4 g·L-1 for a 50 mg·L-1 MB concentration. Equilibrium data pertaining to MB adsorption were subjected to fitting with different models, namely Langmuir, Freundlich, and Temkin. Notably, the Langmuir model exhibited the best fit, revealing a maximum monolayer adsorption capacity of 500 mg·g-1 at 25 °C, and the adsorption kinetics closely followed a pseudo-second-order model.

Enhanced visible light-assisted photocatalytic activity of g-C3N4 decorated with ZIF-8 and AgI ternary heterojunctions

Fabrication of a suitable photocatalyst system that responds to visible light has become a requirement for photocatalytic environmental remediation processes. For better transfer/separation of photogenerated-charges, successful interfacial engineering to build photocatalytic heterojunctions is essential for improving the photodegradation performance. Herein, ternary composites of zeolitic-imidazolate-framework-8 (ZIF-8) coupled with AgI nanoparticles assembled on g-C3N4 have been fabricated, characterized using XRD, FESEM, EDX, TEM, PL, UV–visible DRS, and N2-adsorption–desorption, and used as visible-light-driven photocatalysts for photocatalytic destruction of methylene blue (MB). The ternary AgI/ZIF-8/g-C3N4 photocatalyst achieved superb photodestruction activity (94.2 %) within 120 min. Besides, the first-order degradation rate constant reached 0.02431 min−1, which was nearly 1.5, 2.5, 4.5, and 5.5 times greater than that reached by ZIF-8/g-C3N4 (0.01628 min−1), g-C3N4 (0.00941 min−1), AgI (0.00542 min−1) and ZIF-8 (0.00441 min−1), respectively. The improved photocatalytic behavior was accredited to the synergistic influence of the photo-charge carrier transfer/separation pathway and the electron mediation assisted by ZIF-8. The trapping tests supported the recommended photocatalytic mechanism, which suggested that the O2− radicals were the main reacting agents in this process. The parameters affecting the photodegradation, including the AgI/ZIF-8/g-C3N4 dose, the solution pH, and the MB concentration were systematically tested in this work. Furthermore, the AgI/ZIF-8/g-C3N4 demonstrated good degradation stability after multi-consecutive rounds (only 1 % deduction in its activity after 5 rounds), and thus, it is projected to be a promising photocatalyst in wastewater treatment.

Methylene blue adsorption on Y-zeolite as a nano-porous adsorbent: equilibrium and kinetic studies

ABSTRACT The elimination of dye pollutants from industrial wastewaters, notably from sectors such as textiles and dyeing, remains a pivotal aspect of pollution mitigation endeavours. This research introduces an innovative strategy employing Y zeolite as a nano-porous adsorbent for eliminating methylene blue (MB), a prevalent cationic dye. Y zeolite was synthesised via hydrothermal technique. Through methodical experimentation, the impact of temperature, contact time, concentration, pH and adsorbent quantity on removal efficiency were examined with optimal conditions achieving 93.83% MB removal. The synthesised Y zeolite underwent characterisation utilising diverse techniques, including SEM, TEM, XRD, BET, and FTIR, which elucidated the structural and chemical characteristics. The surface area and pore diameter of Y zeolite were determined to be 229.1 m2/g and 20.3 Å, respectively. Utilisation of Response Surface Methodology (RSM) using design expert software facilitated the exploration of influential parameters, such as pH, temperature, contact time, adsorbent quantity, and MB concentration. The optimal conditions of pH = 7, temperature = 43°C, contact time = 85 min, adsorbent dosage = 0.5 g/L, and initial concentration = 30 ppm were obtained. Furthermore, reusability and durability of Y zeolite through multiple cycles of MB adsorption was assessed, revealing a retained efficiency of ~ 70% after 5 consecutive cycles. Kinetic studies confirmed pseudo-2nd-order model, emphasising chemisorption as the rate-limiting step. Equilibrium data fitting to the Langmuir isotherm highlighted the homogeneity of active adsorption sites on the zeolite surface, emphasising a high adsorption capacity. In conclusion, this study offers a promising solution for the removal of MB from aqueous solutions using Y zeolite as a nano-porous adsorbent. The findings underscore the importance of zeolite’s porosity and surface characteristics in enhancing adsorption efficiency, providing valuable insights for future applications in water treatment and environmental remediation efforts. This research showed that Y Zeolite is effective, low cost, eco-friendly, and can be regenerated as an adsorbent to eliminate MB from aqueous systems.

Photocatalytically active layered double hydroxide-PVDF composite membranes for effective remediation of dyes contaminated water

In this work, polyvinylidene fluoride (PVDF) intercalated CuFe layered double hydroxides (LDH) membranes were fabricated and investigated for UV-LED/persulfate degradation of methylene blue (MB), crystal violet (CV), methyl orange (MO), and Eriochrome black T (EBT) dyes from water. The PVDF-CuFe membrane exhibited improved heterogeneity, surface functionality (CuO, Fe–O, Cu–O–Fe), surface roughness, and hydrophilicity. The process parameters were optimized by response surface methodology, and maximum MB removal (100%) was achieved within 45.22–178.5 min at MB concentration (29.45–101.93 mg/L), PP concentration (0.5–2.41 g/L) and catalyst dosage (1.84–1.95 g/L). The degradation kinetics was well described by a pseudo-first-order model (R2 = 0.982) and fast reaction rate (0.029–0.089/min). The MB dye degradation mechanism is associated with HO·/SO4•− reactive species generated by Fe3+/Fe2+ or Cu2+/Cu+ in PVDF-CuFe membrane and PP dissociation. The PVDF-CuFe membrane demonstrated excellent recyclability performance with a 12% reduction after five consecutive cycles. The catalytic membrane showed excellent photocatalytic degradation of crystal violet (100%), methyl orange (79%), and Eriochrome black T (60%). The results showed that UV-LED/persulfate-assisted PVDF-CuFe membranes can be used as a recyclable catalyst for the effective degradation of dye-contaminated water streams.