Methylene Blue Removal Research Articles

Surface enriched ternary hybrid via interfacial polymerization as an effective adsorbent for dye removal

Methylene blue (MB) is a carcinogenic pollutant that can negatively affect both human health and marine life. Developing effective adsorbents for MB removal is therefore crucial for ensuring safe human life and mitigating environmental issues. Herein, we present an interfacial polymerization to synthesize polydopamine assisted multi-walled carbon nanotubes stitched graphene oxide (PDA@MWNTs/GO) as an effective adsorbent for MB removal. Stitching the PDA layer interfacially onto MWNTs/GO effectively prevents disintegration, diminishes agglomeration/restacking issues, and maximizes adsorption sites. The inherent catecholamine functionality within the PDA layer significantly enhances hydrophilicity. These distinctive characteristics endowed the PDA@MWNTs/GO composite with exceptional adsorption capacity for the cationic MB. The effects of MB concentration, pH, and temperature on the dye solution were thoroughly investigated. The results of the adsorption isotherm and kinetics analysis revealed conformity with the Langmuir isotherm model and adherence to the pseudo-second-order kinetic model. Moreover, PDA@MWNTs/GO demonstrated removal efficiency, exceeding 90% after three consecutive cycles of reuse. The adsorption mechanism was driven by electrostatic attraction and π–π stacking. The superior adsorption performance, attributable to the diverse functionalities and high removal efficiency, demonstrates the potential of PDA@MWNTs/GO as an efficient adsorbent for MB and can also function for other cationic dye impurities.

Structural Analysis and Adsorption Studies of (PbO, MgO) Metal Oxide Nanocomposites for Efficient Methylene Blue Dye Removal from Water.

In the present work, magnesium oxide (MgO) and lead oxide (PbO) nanoparticles were prepared by the co-precipitation method. Their structural parameters and morphology were investigated using XRD, HRTEM, and FTIR. The formation of the phases was seen to have small average crystallite sizes and an orthorhombic crystal structure for both MgO and PbO nanoparticles. The results of HR-TEM showed irregularly shaped nanoparticles: quasi-spherical or rod-like shapes and spherical-like shapes for MgO and PbO nanoparticles, respectively. The produced nanoparticles' size using X-ray diffraction analysis was found to be 17 nm and 41 nm for MgO and PbO nanoparticles, respectively. On the other hand, it was observed from the calculations that the optical band gap obeys an indirect allowed transition. The calculated values of the band gap were 4.52 and 4.28 eV for MgO and PbO NPs, respectively. The MB was extracted from the wastewater using the prepared composites via absorption. Using a variety of kinetic models, the adsorptions were examined. Out of all the particles, it was discovered that the composites were best. Furthermore, of the models currently under consideration, the pseudo-second-order model best fit the degradation mechanism. The resultant composites could be beneficial for degrading specific organic dyes for water purification, as well as applications needing a wider optical band gap.

Arthropods-mediated Green Synthesis of Zinc Oxide Nanoparticles using Cellar Spider Extract: A Biocompatible Remediation for Environmental Approach

This study presents an eco-friendly approach to synthesizing zinc oxide nanoparticles (ZnO NPs) using extracts from cellar spiders, addressing environmental and health concerns associated with conventional methods. The spider extract efficiently reduced zinc acetate dihydrate, and the synthesized ZnO NPs underwent comprehensive quantitative characterization, including size, shape, morphology, surface chemistry, thermal stability, and optical properties using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential measurements, thermogravimetric analysis (TGA), and UV-vis spectroscopy. The nanoparticles exhibited intended characteristics, and their adsorption capability for methylene blue (MB) was quantitatively assessed using the Freundlich isotherm model and pseudo-second-order kinetic model, providing numerical insights into MB removal efficiency. The study demonstrates the potential of these green-synthesized ZnO NPs for applications in environmental remediation, wastewater treatment, and antibacterial therapies, contributing to both sustainable nanomaterial development and quantitative understanding of their functional properties.

Melamine-Maleic Acid Polyamide Adduct / Polyacrylonitrile Nanofibers as a Novel Adsorbent for Removal of Methyelene Blue Dye from Aqueous Solutions

Efficient removal of methylene blue (MB) dye from aqueous solutions is crucial for addressing environmental pollution. This study investigates the potential of Melamine-maleic acid polyamide adduct/polyacrylonitrile (ME-MA amide polymer/PAN) nanofibers as a novel adsorbent for MB dye removal. Characterization via scanning electron microscopy (SEM) revealed surface morphology changes, with fiber diameters ranging from 1 to 3 μm. Thermal stability analysis demonstrated enhanced stability for ME-MA/PAN compared to pure PAN fibers. Fourier transform infrared (FT-IR) analysis confirmed the presence of hydroxyl, amide, and thiol groups on the nanoparticle surface, covalently attached to the nanofiber surface. Through electrospinning, ME-MA/PAN composites were synthesized, showing promising capabilities for dye removal. Optimal conditions were observed at pH 12 and a ME-MA PAN dose of 0.02 g. MB removal efficiency increased with higher initial dye concentrations, peaking at 30 mg/L, and higher temperatures up to 40°C. Adsorption isotherm models indicated Langmuir adsorption capacity (Qm) of 111.10 mg g−1 and a separation factor (RL) of 0.297, with Freundlich constants (1/n) and KF values of 0.418 and 22.9, respectively. Kinetic and thermodynamic studies revealed favorable conditions for MB dye removal, validating ME-MA amide polymer/PAN nanofiber composites as environmentally friendly and effective materials for eliminating toxic MB dye from aqueous solutions. This research highlights the potential of ME-MA/PAN nanofibers in addressing dye pollution, suggesting their application in wastewater treatment for sustainable environmental management. Further investigation into regeneration methods and scalability is recommended for practical implementation in real-world scenarios.

Methylene blue dye efficient removal using activated carbon developed from waste cigarette butts: Adsorption, thermodynamic and kinetics

This study aimed to obtain activated carbon using waste cigarette butts, which is one of the most harmful and toxic environmental materials. In addition, cigarette butts were converted into activated carbon in the thermal carbonization stage using ZnCl2 (1:2 ratios by mass) as a chemical activator. Brunauer-Emmett-Teller test, Fourier transform infrared spectrometry, Scanning electron microscope, and Elemental analysis were used to determine the activated carbon’s surface morphology, elemental composition, functional group, and surface properties. As a result of the Brunauer-Emmett-Teller test, it was observed that the activated carbon obtained had a high surface area of 667.9 m2/g. In the study, it was determined that the Langmuir model can best describe the adsorption isotherm model. In addition, the maximum adsorption capacity of activated carbon for methylene blue dye was 285.7 mg g −1 at 25 °C. The results obtained in the study support that the pore structure of cigarette butts will be one of the strong alternatives in the production of activated carbon for the removal of methylene blue dye.

Computational intelligence for empirical modelling and optimization of methylene blue adsorption phenomena utilizing an activated carbon‐supported [Co(NH3)6]Cl3 complex

AbstractThe study focuses on the efficiency of hexaamminecobalt (III) chloride (HACo, [Co(NH3)6]Cl3) immobilized on activated carbon for removing methylene blue (MB) from water solutions. The primary objective of this study was to assess the sorption performance of HACo immobilized on activated carbon in removing MB from water solutions. Additionally, predictive models were developed to optimize the MB removal percentage. Lastly, the study aimed to determine the optimal conditions for achieving maximum MB removal. Samples were characterized using scanning electron microscopy. Batch sorption experiments were conducted to analyze the impact of MB concentration, adsorbent mass, pH, temperature, and contact time. Predictive models were built using multiple linear regression and neural network techniques, specifically artificial neural networks (ANN) and hybrid ANN–particle swarm optimization (ANN‐PSO). The PSO‐ANN model with a single hidden layer of eight neurons trained using the Levenberg–Marquardt algorithm demonstrated high accuracy in predicting MB removal percentage, with mean absolute percentage error (MAPE) = 0.083788, root mean square error (RMSE) = 0.11441, and R2 = 0.99693. The MB adsorption process followed a mono‐layer with one energy model and a pseudo‐first‐order kinetic model. Optimization using the genetic algorithm revealed that the maximum MB removal percentage of 99.56% is achievable at an MB concentration of 9.36 mg/L, adsorbent mass of 15.72 mg, and temperature of 311.2 K. The study confirms the effectiveness of HACo immobilized on activated carbon for MB removal. The PSO‐ANN predictive model proved superior in accuracy compared to empirical models. Optimization results provide the optimal conditions for maximizing MB removal, offering valuable insights for practical applications.

Photocatalytic activity of ZnO doped Nano hydroxyapatite/GO derived from waste oyster shells for removal of Methylene blue.

Hydroxyapatite (HAp) stands as an inorganic compound, recognized as a non-toxic, bioactive ceramic, and its composition closely resembles that of bone material. In this study, nHAp was prepared from waste oyster shells, which are biowaste rich in calcium carbonate. nHAp with its unique catalytic property can be used as an adsorbent in various fields, including wastewater treatment. nHAp with an exceptional surface adsorbent with excellent chemical stability, enabling its catalytic function. Nano hydroxyapatite doped with Zinc oxide (ZnO) by wet chemical precipitation and made into a composite with Graphene oxide (GO) by modified hummers method followed by grinding, which was taken as 9:1 ratio (nHAp/ZnO and GO) of weight, enhances its tensile and mechanical strength. The energy band gap of nHAp photocatalyst was evaluated as 3.39eV and that of the in nHAp/ZnO/GO photocatalyst was narrowed to 1.77eV. The ternary nanocomposites are very efficient in generating the photogenerated electrons and holes, thereby improving the degradation potential of dye effluents to by-products such as CO2 and H2O. The nanocomposites photocatalyst were characterized by FTIR, XRD, SEM, TEM, EDS, XPS, DRS, and BET techniques. The UV-visible study shows the complete dye degradation efficiency of the prepared nanocomposites photocatalyst. In this study, the prepared nanocomposites nHAp/ZnO/GO have studied their efficiency for the removal of MB dye in a batch process by varying the dosage from 0.1 to 0.5g, and the effects of dosage variations, pH, kinetic, scavenger study were evaluated at a time interval of 30min. The removal of dye was found to be 99% at 150min of 0.3g dosage and pH = 12 is most favorable as it reached the same percentage at 90min. The as-prepared nanocomposite nHAp/ZnO/GO fits the kinetic rate constant equation and shows a pseudo-first-order reaction model. This study indicates the suitability for dye removal due to the synergistic effect and electrostatic interaction of the synthesized ternary nanocomposite, which shows the potential, socially active, low-cost-effective, eco-friendly, and safe for photocatalytic degradation of MB from wastewater.

Replacing Potassium Hydroxide with Carbide Lime Waste in Preparing Sludge-Based Activated Carbon for Methylene Blue Removal from Aqueous Solutions

Replacing Potassium Hydroxide with Carbide Lime Waste in Preparing Sludge-Based Activated Carbon for Methylene Blue Removal from Aqueous Solutions

Electrocoagulation employing recycled aluminum electrodes for methylene blue remediation

This work focuses on the recycling of aluminum-based metal joinery waste in the context of the treatment of wastewater containing organic materials, such as dyes, by electrocoagulation (EC); aluminum scraps were used as electrodes to process synthetic solutions of the methylene blue (MB) dye. The study investigated the effect of different parameters, including pH (3, 4, 5, 7, 9, 11) current density (100, 150, 200, 250 A/m2), electrolysis time (30, 60,120 min), sodium chloride concentration (0.5, 1, 2 g/L) and the initial dye concentration (10, 20, 45, 60 mg/L) on the removal efficiency of MB. The results showed that the optimum conditions for MB removal were achieved at the original pH of the solution which is 7 using a current density of 200 A/m2 and an inter-electrode distance of 1 cm with 10 mg/L as a dye concentration and 2 g/L of electrolyte. The removal efficiency under these conditions can reach 97.81 %. An estimation was made of the electrical energy needed to attain the ideal removal, which was found to be approximately 0.97kWh/g removal dyestuff the electrode consumption was 0.13 (kgAl /g of dyestuff), with an operation cost of 0.106 ($/g of dyestuff). The study suggests that EC using only two aluminum electrodes is efficient technique for the removal of MB from synthetic wastewater. The removal of the dye was monitored by UV–visible spectroscopy and scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) is used for the identification of the functional groups of MB in the obtained sludge by the EC process; and the aluminum electrodes surfaces, before and after treatment, were characterized by scanning electron microscopy (SEM) and Dispersive Energy Spectroscopy (EDS).

A new nanocomposite as adsorbent and catalyst for enhanced removal of methylene blue

In this study, we present, for the first time, the preparation and characterization of a few-layer graphene (FLG)/Fe3O4/Ag nanocomposite functionalized with polyacrylic acid (PAA) polymer for the removal of methylene blue (MB). X-ray Powder Diffraction (XRD) analysis confirmed the coexistence of Fe3O4 and Ag nanoparticles. The results demonstrate a high adsorption ability (qmax 141.60 mg/g) of the nanocomposites, achieving 98% removal of MB dye within 40 min at a concentration of 50 mg/L, with a nanoadsorbent amount of 100 mg. Furthermore, the findings indicate that the FLG/Fe3O4/Ag@PAA adsorbent maintains high dye removal efficiency over four consecutive cycles. The FLG/Fe3O4/Ag@PAA nanocomposites exhibit significantly enhanced catalytic reduction activity on organic pollutants. The reduction of MB can be completed in 300 s in the presence of NaBH4 as a reducing agent, using 5 mg of nanocatalyst and a concentration of MB dye of 50 mg/L. These results suggest that the nanocomposite can serve not only as an adsorbent but also as a promising catalyst for the reduction of organic dyes.

Enhancing methylene blue removal: Synthesis, characterization, and performance evaluation of chemically activated carbon adsorbents

In response to the pressing environmental issue of efficiently removing methylene blue (MB) from aqueous solutions, this study introduces a novel approach utilizing activated carbon (AC) synthesized via a two-stage activation process involving zinc chloride (ZnCl2) and ammonium sulfate ((NH4)2SO4). SEM analysis confirms the development of a porous structure at distinct activation temperatures (700 °C and 260 °C), while comprehensive characterizations, including FTIR, BET, TGA, CHNOS, and XRD, provide valuable insights into the structural and chemical properties of the synthesized AC. Optimization of the activation process at the second stage using (NH4)2SO4 yields a remarkable surface area of 939.63 m2/g, crucially enhancing functional groups such as Hydroxyl (O-H) and Carbonyl (CO). The experimental design involved optimizing various parameters, including contact time (0–180 mins), initial concentration (200–500 ppm), temperature (25–55 °C), pH (4−10), and adsorbent dosage (0.4–0.65 g). Batch adsorption optimization experiments demonstrate exceptional efficiency, achieving 99.91 % MB removal and a 90.827 mg/g capacity. Furthermore, Langmuir and second-order kinetic model fitting indicate favorable adsorption behavior, supported by thermodynamic analysis revealing an endothermic process. Notably, AC exhibits excellent regenerative potential over four cycles, emerging as a promising candidate for advancing water purification practices; the modified AC achieves WHO standards for MB removal in drinking water.

Optimization of methylene blue removal by H3PO4 thermochemically treated mixed pineapple peel and algae adsorbent and insight on the adsorption mechanism

Optimization of methylene blue removal by H3PO4 thermochemically treated mixed pineapple peel and algae adsorbent and insight on the adsorption mechanism

Preparation of highly microporous activated carbon by utilizing inherent iron in coal through CO2 and steam co-activation for improving CO2 capture and methylene blue removal

Pore-tailoring by utilizing the inherent iron mineral in coal for highly microporous activated carbon (AC) preparation for boosting adsorption ability is a promising strategy. In this work, AC-XFeS2 (X indicates the contents of pyrite in coal, 0–3 wt.%) was prepared via blending demineralized Taixi coal and pyrite and followed by CO2 and steam co-activation. The iron minerals transformation, AC physicochemical textural development and performance were investigated by various analyses. The results indicate that: (1) Pyrite (FeS2) can transform into magnetite (Fe3O4) and hematite (Fe2O3) during CO2 and steam co-activation. Pyrite declines the graphitization degree and enhances the increment of AC’s C=O, COO, and π–π* content. Pyrite favors the increase of AC’s micropore porosity. High SBET and Smic of 1587 m2/g and 949 m2/g of AC-1FeS2 were achieved, which is higher by 13.5% and 83.6% than AC of 1398 m2/g and 517 m2/g, respectively. (2) The CO2 adsorption capacity of AC-1FeS2 is up to 2.06 mmol/g at 25 °C and 1.0 bar, which is higher by 11.3% than 1.85 mmol/g of AC. The enhancement of micropore by pyrite is the main aspect of improving CO2 capture. (3) AC-1FeS2 presents maximum MB adsorption capacity, reaching 63.3 mg/g, which is higher by 19.3% than 53.3 mg/g of AC. A serious of kinetics models was studied and the MB adsorption process could be better reflected by Pseudo second-order kinetics (R2=0.9538). The enhanced pore-filling, π–π* stacking and C=O complexation are one aspect of improving MB removal. In addition, the effect of Fe-O bonds or magnetic particles including Fe3O4 also enhances MB removal. The results of this investigation could provide new avenues and theoretical support for cost-effective AC with highly microporous production by utilizing high-iron-sulfur coal, to some extent, guide the actual industrial application.

Mesoporous magnetic biochar derived from common reed (Phragmites australis) for rapid and efficient removal of methylene blue from aqueous media

A novel mesoporous magnetic biochar (MBC) was prepared, using a randomly growing plant, i.e., common reed, as an exporter of carbon, and applied for removal of methylene blue (MB) from aqueous solutions. The prepared sorbent was characterized by nitrogen adsorption/desorption isotherm, saturation magnetization, pH of point of zero charges (pHPZC), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The obtained MBC has a specific surface area of 94.2 m2 g−1 and a pore radius of 4.1 nm, a pore volume of 0.252 cm3 g−1, a saturation magnetization of 0.786 emu g−1, and a pHPZC of 6.2. Batch adsorption experiments were used to study the impact of the physicochemical factors involved in the adsorption process. The findings revealed that MB removal by MBC was achieved optimally at pH 8.0, sorbent dosage of 1.0 g L−1, and contact time of 30 min. At these conditions, the maximum adsorption was 353.4 mg g−1. Furthermore, the adsorption isotherm indicated that the Langmuir pattern matched well with the experimental data, compared to the Freindlich model. The ∆G was − 6.7, − 7.1, and − 7.5 kJ mol−1, at 298, 308, and 318 K, respectively, indicating a spontaneous process. The values of ∆H and ∆S were 5.71 kJ mol−1 and 41.6 J mol−1 K−1, respectively, suggesting endothermic and the interaction between MB and MBC is van der Waals type. The absorbent was regenerated and reused for four cycles after elution with 0.1 mol L−1 of HCl. This study concluded that the magnetic biochar generated from common reed has tremendous promise in the practical use of removing MB from wastewater.Graphic

Engineered K-doped ZnO/borneol based hydrogel composite material for led-based photocatalytic degradation of methylene blue and evaluation of antimicrobial activity

The significant improvement of decolorization and disinfection technologies has been a hotspot in wastewater reutilization. In this study, we realized a novel construction of K-doped nano-ZnO and borneol based hydrogel composite material (K-ZnO/B-hydrogel) by low-temperature in situ sol–gel growth. The techniques such as fourier transform infrared (FTIR), X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and X-ray energy dispersive spectroscopy (EDS) were applied to recognize the synthesized hydrogel. The results revealed that K-doped ZnO nanoparticles had been uniformly decorated onto the B-hydrogel. Ultraviolet-visible (UV–vis) absorption spectra showed that impurity doping of potassium element into ZnO could reduce the band gap, improving the visible light absorption efficiency. Under LED illumination, the photodegrading rate of K-ZnO/B-hydrogel was approximately 2.3 times greater than that of K-ZnO/B-hydrogel on methylene blue (MB) removal. Remarkably, aside from CO2 and H2O, no by-products were generated during the photodegradation process. In addition, the antimicrobial activities against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of K-ZnO/B-hydrogel achieved up to 99.9%, which were at least 1.5 times higher than K-ZnO/B-hydrogel. This composite will push ahead with a closed-loop wastewater treatment system for dye and pathogenic microorganism disposal, which combines the excellent adsorption ability of hydrogel and the outstanding photocatalytic ability of ZnO nanoparticles with easy sample handling and separation, and help to eliminate secondary pollution.

Optimization of Fe/Ni, Fe/Cu bimetallic nanoparticle synthesis process utilizing concentrated Camellia sinensis extract solution and activity evaluation through methylene blue removal reaction

In this study, we introduce a synthesis process of bimetallic nanoparticles (BNPs) Fe/Ni and Fe/Cu utilizing concentrated Camellia sinenis extract that was optimized with a solvent ratio of ethanol/H2O 4/1 (v/v), a metal ratio of 5/1 (w/w), a total polyphenol content (TPC) in the solution of 12.5 g.l−1, pH = 3–4, 25 °C, and the reaction time ranging from 30 min to 50 min. The structural and morphological characteristics of the resulting materials were determined using several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The maximum removal efficiency of methylene blue (MB) by BNPs Fe/Ni and Fe/Cu materials was found to be 88.60% and 91.06%, respectively, at a concentration of MB = 25 mg.l−1 and 25 °C. According to the results of the kinetic modeling study, the adsorption process of MB on the two BNPs materials followed second-order kinetics, with the maximum adsorption capacities of MB on Fe/Ni and Fe/Cu BNPs being 26.94 mg.g−1and 28.00 mg.g−1, respectively.

Revolutionizing photocatalysis: Synergistic enhancement of structural, optical, and photodegradation properties in Be-doped V2O5 nanoparticles for efficient methylene blue removal

This study focuses on the investigation of beryllium (Be) doping in V2O5 nanoparticles and the coordinated effects it has on the structural, optical, and photocatalytic characteristics of the material. XRD analysis reveals modifications in the orthorhombic structure upon Be doping, decreasing crystallite size (68.7–46.6 nm), and increased dislocation line density. Optimizing charge carrier mobility and separation is crucial for improving photocatalytic activity, and this is achieved via these adjustments. Raman spectra indicated increased crystallinity with Be doping. The optical analysis demonstrated an adjustable band gap (2.47–2.60 eV) and reduced refractive index (2.49–2.45), that enhance light absorption efficiency. More importantly, the study shows that Be-doped V2O5 nanoparticles have better photocatalytic activity for the breakdown of methylene blue, indicating its potential for environmentally friendly remediation. The present work contributes to the advancement of customized doping approaches for maximizing V2O5 functioning across a range of applications by clarifying the complex impacts of Be doping.

Optimizing Methylene Blue Dye Adsorption onto Liquid Natural Rubber-Based Hydrogel: Kinetics, Isotherms and Reusability

In recent years, notable advancements have taken place in the textile industry, particularly with the widespread use of synthetic dyes such as methylene blue (MB). However, the environmental impact of these dyes has raised significant concerns. Their potential to influence both chemical and biochemical demand poses risks, leading to potential disruptions in aquatic plant photosynthesis. Additionally, concerns exist regarding the toxicity and potential carcinogenicity of these dyes to humans. This study achieved successful hydrogel synthesis through the efficient utilization of ultrasonic methods, combining liquid natural rubber (LNR), acrylic acid (AAc), and pectin (Pc) to adsorb MB from aqueous solutions. Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were employed to analyze the structure. Utilizing Response Surface Methodology (RSM), the study investigated the effects of the AAc:LNR weight ratio and Pc weight on hydrogel preparation for MB removal. This led to the development of a quadratic polynomial model with an ANOVA-derived R2 value of 0.9970. Optimal conditions for hydrogel production were identified as a 3.00 g/g AAc:LNR weight ratio and 0.0325g of Pc, resulting in an impressive 99.07% MB removal effectiveness. The limit of detection (LOD) for methylene blue adsorption was calculated at 0.64 ppm. The kinetics and isotherms of MB removal were described by the pseudo-second-order and Freundlich models, respectively. Furthermore, the investigation into hydrogel reusability demonstrated its capability for up to five utilization cycles. The LNR/AAc/Pc hydrogel exhibits promising potential as an effective, cost-efficient, and environmentally conscious adsorbent for MB removal. This makes it applicable to water treatment scenarios involving cationic dyes.

Functional properties and continuous adsorption process of Arenga pinnata shell and its porous biochars for aqueous methylene blue removal

Arenga pinnata shell, an agricultural-processing residue, was used as an alternative precursor for synthesizing Arenga pinnata shell particles (ASP), Arenga pinnata shell biochar (ASB), and Arenga pinnata shell activated biochar (ASAB) for methylene blue (MB) adsorption. Optimized adsorbent was observed for ASAB fabricated via an impregnation ratio of KOH to ASP of 0.5:1 (w/w) at 700 °C for 30 min of activation time under N2 pyrolysis, with a surface area, pore volume, and average pore diameter of 967 m2/g, 0.572 cm3/g, and 2.47 nm, respectively. The adsorbent also possesses the largest carbon constituent (90.4 %), negative surface charge (−36.4 mV), and abundant oxygen-containing functional groups. Dynamic MB adsorption properties on the adsorbents from the aqueous environment under continuous mode at 25 °C were determined using the Thomas and Yoon-Nelson models. Although the ASP and ASB presented comparatively favorable adsorption properties, the optimum adsorption performance was observed for the ASAB. Its superior functional features contributed to the largest adsorption capacity of 203.86 mg/g. The elemental composition analysis indicated the presence of sulfur on the ASAB surface, which supported the findings. This research demonstrates the utility of Arenga pinnata shell as an eco-friendly precursor for high-performance adsorbent fabrication with excellent MB adsorption properties.

Improving Adsorption Efficiency of Recycled Activated Carbon from Household Water Purifiers through Sonication

Objectives:This study evaluated the potential of recycled activated carbon from household water purifiers as an adsorbent for removing methylene blue. It aimed to achieve resource recycling and dyeing wastewater treatment through the sonication modification of recycled activated carbon.Methods:After sieving recycled activated carbon from water purifiers to a particle size of 75-150μm, the material, in this paper referred to as PCB-S, was processed using sonication to enhance its adsorption capacity. The characteristics of PCB-S were analyzed using SEM, XRD and BET analysis. To evaluate its efficacy, adsorption experiments were carried out varying the following parameters: PCB-S dosage (0.05-0.6gL-1), pH (2.0-10.0), initial concentration of methylene blue (100mgL-1), reaction time (1440 min), and temperature (298 K). The data from these experiments were analyzed using first and second-order kinetic models to understand the reaction kinetics, and the adsorption efficiency was further compared using Langmuir and Freundlich isotherm models. Finally, the thermodynamic properties of the adsorption process between PCB-S and methylene blue were studied to determine its endothermic nature and spontaneity.Results and Discussion:The analysis of the surface characteristics of PCB and PCB-S revealed that sonication significantly altered the pore structure of the activated carbon, leading to increases in both the specific surface area and pore volume. XRD analysis, indicated that sonication had no impact on the crystalline or amorphous structure of the activated carbon. PCB-S demonstrated superior porosity and adsorption capabilities compared to PCB. With a dosage of 0.6gL-1, PCB-S was able to remove 65% of methylene blue from the solution. The adsorption kinetics were best described by a pseudo-second-order kinetic model, with the Langmuir adsorption isotherm fitting the data most accurately. The Gibbs free energy (-1.90~-1.32kJ mol-1) and enthalpy change (7.44 kJ mol-1) confirmed that the adsorption reaction was endothermic.Conclusion:This study confirmed that recycled activated carbon from water purifiers exhibits excellent effectiveness as a dye removal adsorbent when subjected to sonication treatment. Therefore, the possibility of utilizing recycled household water purifier filters as adsorbents is expected to contribute to reducing waste disposal costs by promoting resource recycling.