Initial Methylene Blue Research Articles

Improving Photocatalytic Efficiency with Titanium Dioxide Quantum Dots

Titanium dioxide quantum dots (TiO2-QDs), synthesized using a microwave-assisted method, represent a significant advancement in photocatalysis, particularly in the treatment of environmental pollutants. This study focuses on TiO2-QDs synthesized at 200°C for a duration of 5 minutes, using titanium butoxide as a precursor. Characterization through TEM, XRD, PL, and UV-Vis-DRS analyses revealed uniform quantum dots with an average size of 5.28 nm, a bandgap energy of 3.22 eV, and a crystalline anatase phase, indicative of high photocatalytic activity. Notably, these TiO2-QDs demonstrated exceptional performance in degrading methylene blue (MB) in water, achieving a remarkable treatment efficiency of 97.6% in 120 min, significantly outperforming both conventional titanium dioxide nanoparticles and commercial titanium dioxide materials. The reaction conditions were evaluated based on factors such as catalyst dose, initial MB concentration, and pH. The results indicate that optimal degradation efficiency of MB was achieved at a pH of 7, with a catalyst dose of 0.15 g/L and at a low MB concentration. The efficiency slightly decreased to 94.5% after five reuse cycles, emphasizing its significant reusability and stability. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Cnicus Benedictus roots as a low-cost adsorbent for methylene blue dye removal from aqueous solution: kinetic and equilibrium studies

In this research, Cnicus Benedictus roots powder (CBRP) was utilized as a low-cost adsorbent for removing methylene blue (MB) as a cationic dye from aqueous solution. Characterization of CBRP by Boehm titration method, Fourier transform infrared (FT-IR) and environmental scanning electron microscope (ESEM) indicates the presence of different types of functional groups and a very rough surface filled with cavities, suitable for MB adsorption. The effect of various parameters such as CBRP dose (0.2–2 g/1L), contact time (0–180 min), initial pH (1–10), coexisting anions/cations and the initial MB concentration (100–500 mg L−1) on MB adsorption were examined, the results showed that MB uptake depends on the pH of solution, the electrostatic attraction forces, the formation of H-bonds and π–π interactions are the possible CBRP–MB interaction mechanisms. Adsorption kinetic of MB on CBRP was best represented by linear and non-linear form of the pseudo-second order model. The experimental equilibrium data were best described by linear and non-linear forms of Langmuir and Redlich–Peterson isotherm models (R 2> 0.98) with a maximum MB adsorption capacity of 85.47 mg g−1 at 25 °C, the adsorption efficiency R (%) was greater than 90 (%). MB adsorption-desorption experiments showed the reusability of CBRP for five consecutive cycles. According to the obtained results, CBRP can be used as a natural adsorbent material for cationic dyes removal from aqueous solution.

CARBON-SILICA COMPOSITE AS ADSORBENT FOR REMOVAL OF CATIONIC DYE (METHYLENE BLUE)

The aim of this research was to synthesize carbon-silica composite (CSC) as an adsorbent for cationic dye removal from wastewater. Molasses, a by-product of the sugar industry, was successfully utilized to prepare CSC by sol-gel method with tetraethoxylsilane (TEOS) as silica source. The physicochemical properties of the composites were studied by N2 adsorption, FTIR and TGA. The highest specific surface areas of CSC was 144 m2/g at a molasses/TEOS ratio of 0.8, with a mesopore volume of 83% and average pore width of 9.71 nm. This optimal CSC was evaluated for methylene blue (MB) adsorption using batch experiments under varying adsorption times and initial MB concentrations. Adsorption equilibrium was reached within 14 h and the pseudo-second order equation provided the adequate fit for the kinetic studies, suggesting that dye adsorption was limited by chemisorption. The equilibrium data were best described by the Sips model with a maximum adsorption capacity of 180.22 mg/g. The CSC derived from molasses is considered a potentially promising adsorbent for cationic dye removal in wastewater.

Sugarcane peel ash as a sorbent for methylene blue

Sugarcane peel waste (SPW) modified by combustion was used as a sorbent for methylene blue (MB) in aqueous medium under the influence of parameters such as pH of the medium, initial MB concentrations, contact time, SPW dosage, and temperature using batch experiments. The microstructure of the adsorbent was analyzed using Fourier infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffractometer (XRD). The quantity (mg/g) of adsorbed MB increased with increased contact time, rise in dye concentration, as well as the solution pH. Similarly, the temperature of the system improved the sorption effectiveness with maximum sorption capacity of 65.4 and 81.2% at 45 °C and 55 °C for USPW and MSPW, respectively. At an initial MB concentration of 100 mg/L, temperature of 45 °C and 55 °C, pH of 4, and reaction times of 80 and 60 min for unmodified sugarcane peel waste (USPW) and modified sugarcane peel waste (MSPW), respectively, optimal MB adsorption of 22.6 and 33.2 mg g-1, respectively, was achieved.

Methylene blue adsorption by chemical-activated Trichanthera gigantea leaf

ABSTRACT This study investigated the potential of NaOH-treated Trichanthera gigantea leaf (TGL) powder as a sustainable, low-cost biosorbent for methylene blue (MB) removal from wastewater. Characterization using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller, and energy-dispersive X-ray spectroscopy (EDX) techniques confirmed favorable morphology, identifying micropores, suitable functional groups, notable surface area, pore volume, and elemental diversity. Batch experiments systematically investigated the influence of operational parameters, including contact time, initial MB concentration (5–35 mg/L), pH (2–10), and biosorbent dosage (2–10 g/L) on adsorption performance. The Langmuir isotherm model best represented the experimental data (R² values of 0.993 and 0.9725), indicating favorable adsorption (RL < 1) and maximum MB adsorption capacities of 0.822 and 0.330 mg/g for treated and untreated TGL, respectively. Statistical analysis (ANOVA) results further identified the most significant factors influencing MB biosorption. These findings highlight the potential of NaOH-treated TGL powder as an effective and eco-friendly solution for removing MB dye from industrial effluents, contributing to sustainable wastewater treatment and environmental protection.

Adsorption Capacity and Efficiency of Composite Thin Sheet Made of Chitosan-Activated Carbon on The Adsorption of Methylene Blue

Abstract Methylene blue (MB) is a waste dye produced by textile industries. One way to reduce MB in polluting the environment is using MB adsorbent materials, such as chitosan (CS)-based composites. This research aims to investigate the adsorption capacity and efficiency of chitosan-activated carbon composites (CS-AC), which are in the form of thin sheets, on MB adsorption. The composite was made by manually mixing the chitosan and activated carbon, and then the mixture was poured into a dish and dried at around 50 °C until a dry, thin sheet was formed. The composites were prepared with varying activated carbon mass concentrations (25%, 50%, 75%, and 100% of chitosan mass). The MB adsorption measurements were carried out using UV-Vis spectroscopy. Adsorption capacity and adsorption efficiency increase with increasing activated carbon content, and the composite containing activated carbon mass 100% of chitosan mass shows the highest values, namely 11.51 mg/g and 95.93%, respectively. Furthermore, the values of adsorption capacity and adsorption efficiency are also influenced by the initial MB concentration and mass of the adsorbent. The adsorption capacity increases with increasing initial MB concentration but decreases with increasing adsorbent mass. Adsorption efficiency increases with increasing initial MB concentration and adsorbent mass.

Box-Behnken design optimization of 2D Ti3C2Tx MXene nanosheets as a microwave-absorbing catalyst for methylene blue dye degradation

The 2D MXene Ti3C2Tx was synthesized from the precursor MAX phase Ti3AlC2 by etching the Al layer using hydrofluoric acid. Different Characterization techniques were employed to investigate the properties of the synthesized Ti3C2Tx. The degradation of methylene blue (MB) dye under microwave irradiation in the presence of the prepared 2D MXene was studied. It was found that the synthesized Ti3C2Tx was an excellent microwave catalyst for MB dye degradation, and results obtained were promising. Using this approach, the dye was almost wholly degraded with a degradation efficiency of 99.85 % in only 10 min without adding any oxidant. The degradation was found to follow the pseudo-first-order kinetic model, and the rate constants obtained varied from 0.10 and reached up to 0.67 min−1. The effect of pH, initial MB concentration and catalyst dosage on the MB dye degradation rate has been studied. It was found that carrying out the reaction at pH values ranging from 2 to 10 did not obviously affect its rate. On the other hand, lower initial MB dye concentrations and higher catalyst dosages significantly increased the degradation rate. The high degradation efficiency was found to be maintained for up to five successive catalytic cycles, ensuring the high stability of the synthesized 2D MXene Ti3C2Tx as a catalyst. Optimization of parameters affecting the degradation process was studied using response surface methodology (RSM). According to the Box-Behnken design, the optimal degradation efficiency (99.92 %) could be achieved by adding 21.24 mg of 2D Ti3C2Tx MXene catalyst and using an initial MB dye concentration of 53.06 ppm (mg/L) during a reaction time of 11.93 min.

Scale-bridging And Modelling Study of Graphene Shell Composite Adsorption for Dye Removal in Water Treatment

Continuous fixed-bed adsorption is a cost-effective water-treatment method for dye removal. This research examined parameters such as bed heights (5, 7, and 9cm), initial methylene blue (MB) concentrations (10, 15, and 20mg/L), and feed flow rates (8, 10, 12 and mL/min) on fixed-bed adsorption performance. Our findings showed that the performance was improved under longer exhaustion times not only with increasing column bed heights, but also with decreasing initial MB concentrations and feed flow rates. Of note, the Thomas and Yoon-Nelson models accurately described MB adsorption in a fixed-bed column, with R2 values from 0.7525 to 0.9833. Response surface methodology via central composite design optimized column bed heights and feed flow rates on the duration required to achieve 50% of column breakthrough. The coefficient of determination (R2) and analysis of variance demonstrated the significance of the Two Factor Interaction (2FI) model in fitting the actual values. The optimum conditions were determined to be as follows: a bed height of 5cm; a feed flow rate of 8mL/min; and a duration of 54.74min to achieve 50% of column breakthrough. Lastly, a confirmatory test further verified the precision of the proposed optimum conditions with an error of only 0.02%.

Chitosan‐Carbon Aerogel for Efficient Removal of Methylene Blue Dye: Synthesis, Characterization, Adsorption Mechanism and Antimicrobial Therapies

AbstractChitosan‐carbon aerogel was synthesized via a facile and eco‐friendly method and characterized for its structural and morphological properties. The composite exhibits remarkable adsorption kinetics and a high potential for removing Methylene Blue (MB) dye, attributed to its enhanced surface area, porous structure, and active functional groups. The adsorption capacity of chitosan‐carbon aerogel increased from 38 to 86.8 mg/g as the pH was raised from 2 to 7. The maximum MB adsorption capacity increased from 22 to 632 mg/g as the initial MB concentration increased from 25 to 2000 mg/L. The saturation adsorption capacity of the chitosan‐carbon aerogel was 668 mg/g. After five reuse cycles, the removal efficiency dropped from 89 % to 73.1 %. Antibacterial tests showed that the width of the inhibition zone for S. enterica was 16.2 ± 0.38 mm, indicating similar antibacterial activity for both chitosan and chitosan‐carbon aerogels. These findings underscore the potential of chitosan‐carbon aerogel as a sustainable and cost‐effective solution for dye removal in wastewater treatment.

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.

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.

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.

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.

Visible light induced photocatalytic degradation of methylene blue using carbon fibre cloth - Bismuth oxybromide – Water hyacinth derived silver nanocomposite

Methylene Blue (MB), a frequently used cationic dye, is recognized for its persistence and probable toxicity, making its removal from wastewater an urgent environmental concern. This study reports the solar photocatalytic degradation efficiency of MB by bismuth oxybromide-green silver nanoparticles (AgNPs) as catalyst. AgNPs were produced by the green synthesis method from an invasive aquatic weed water hyacinth (Pontederia crassipes). The AgNPs were doped on Bismuth oxybromide (BiOBr) nanosheets formed on the surface of carbon fibre cloth (CFC) to form the catalyst CFC-BiOBr-Ag. Under optimum conditions of 5 mg/L of initial MB concentration and near-neutral pH, one piece of CFC-BiOBr-Ag photocatalyst (5.78 mg/L) exhibited 95.68% degradation efficiency of MB in 4 h. TOC removal studies showed a removal efficiency of 74.82% after 4 h, indicating the potential for mineralization of MB. Adsorption-photocatalysis-desorption study revealed complete degradation of adsorbed MB at the end of the photocatalytic degradation. Additionally, the catalyst exhibited good reusability, with more than 84.88% degradation efficiency even after five cycles of use. Under direct sunlight, the CFC-BiOBr-Ag catalyst demonstrated MB degradation efficiency of 97.52% after 3 h of treatment. MB breakdown was evidently done by the hole (h+) and the superoxide radical (O2•−). The mechanism of MB degradation was adsorption and subsequent degradation by the CFC-BiOBr-Ag photocatalyst. The prevalent degradation reactions such as demethylation, ring opening, hydroxylation, •OH radicle attack, desulfonication, hydrolysis etc. led to formation of various intermediates which further mineralized to CO2 and H2O.

Hydrothermal chemical modification of red mud for efficient adsorption of methylene blue

ABSTRACT Red mud (RM) is the industrial solid waste produced after alumina extraction from bauxite, and most RM is directly discharged to the landfill yards without any treatment. In this study, modified red mud (MRM) was synthesized by a hydrothermal chemical modification method as an efficient adsorbent for methylene blue (MB) removal. The prepared MRM was characterized by X-ray fluorescence spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectrometer. The effects of reaction time, initial MB concentrations, MRM dosage, temperature, and system pH were investigated in the MB batch adsorption experiments. The results showed that the modification method increased the specific surface area of RM material from 16.72 to 414.47 m2/g. The maximum adsorption capacity of MRM for MB was 280.18 mg/g under the conditions of initial MB concentration of 1000 mg/L, reaction time of 300 min, temperature of 25 ℃, and natural pH of 6.06. Meanwhile, the adsorption kinetics and equilibrium isotherms were demonstrated to fit well with the pseudo-second-order kinetic model and Temkin isotherm, respectively. This study provides a new method for the valorization of RM and demonstrates that MRM can be used as a low cost and environmentally friendly potential adsorbent for the removal of MB from wastewater.

Effectiveness of Porous Durian Shell-based Activated Carbon for Methylene Blue Adsorption

In this study, durian shell-based activated carbon (DAC) was produced via chemical activation method by utilising durian shell and sulphuric acid (H2SO4) as the starting material and activating agent, respectively. The incorporation of H2SO4 in the DAC production process resulted an improvement in the surface properties and adsorption capacity of the produced DAC adsorbent. Field emission scanning electron microscopy analysis further showed that the produced DAC possessed a porous structure which was beneficial for dye adsorption application. Under operating conditions of 500°C and 3 hours carbonisation temperature and time, the Brunauer–Emmett–Teller (BET) surface area, total pore volume and BET average pore diameter were measured to be 242.03 m2/g, 0.028 cm3/g and 2.28 nm, respectively. The adsorption performance of the produced DAC was then investigated using methylene blue (MB) as the model adsorbate. The optimum MB dye removal and adsorption capacity were found to be 92.05% and 0.767 mg/g, respectively, with 0.6 g of DAC dosage, 10 ppm of initial MB dye concentration and 15 min of contact time.

Degradation by photo-Fenton process using Fe-clay as heterogeneous catalyst under sunlight and microwave irradiation

This study presents a newly developed, highly efficient heterogeneous iron-based catalyst (Fe-CY), supported on treated bentonite clay (CY), designed for the degradation of methylene blue (MB) dye. The bentonite clay underwent a two-stage treatment involving physical and chemical processes to produce the designated treated clay (CY), which served as the support material for Fe-CY catalyst preparation using the wet impregnation technique. Subsequently, the performance of the resulting catalyst was assessed in a photo-Fenton reaction aimed at degrading MB dye under both solar and microwave irradiation conditions. To determine the optimal decolorization conditions, several variables, including catalyst dosage, H2O2 quantity, pH, and initial MB concentration in the reaction system, were systematically investigated. Miscellaneous characterization techniques were employed to assess the support, and prepared catalyst. X-ray diffraction (XRD) was used to determine crystallinity, scanning electron microscopy (SEM) to analyze morphological structure, Fourier-transform infrared spectroscopy (FTIR) to identify surface functional groups, energy dispersive X-ray (EDX) analysis for the purpose of elemental analysis, and Brunauer-Emmett-Teller (BET) for analyzing the textural properties. The experimental findings highlight the remarkable effectiveness of the catalyst in degrading methylene blue (MB). Upon exposure to sunlight and microwave irradiation, the catalyst achieved substantial MB color removal rates of 99.5% and 95.5% within 180 and 8 min, respectively. Moreover, the stability of the catalyst was evaluated across three consecutive cycles, revealing a sustained removal efficiency of 83.05%. Finally, a comprehensive investigation into the mechanism behind methylene blue (MB) removal was conducted, revealing insights into the unique catalytic properties of the Fe-clay catalyst.

Synthesis of iron loaded jackfruit peel biochar through microwave heating as a stable and active heterogenous Fenton catalyst for dye degradation

Iron-loaded biochar derived from jackfruit peels (Fe-JP) was synthesised by pyrolysis in a microwave furnace and iron was loaded onto the peels prior to pyrolysis, facilitated by sonication. The primary objective of the investigation was to examine the degradation process of methylene blue (MB) dye and Acid Red 1 (AR1) dye by the using Fe-JP biochar as a heterogeneous Fenton catalyst. The investigation encompassed an examination of the impact of different operating parameters, such as pH, catalyst dosage, and H2O2 concentration. The synthesised Fenton catalyst underwent characterization using Field Emission scanning electron microscopy (FESEM), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques, Fourier transform infrared (FTIR) spectra analysis, Raman spectroscopy, Brunauer-Emmet-Teller (BET) analysis. At a pH of 3, using an initial MB dye concentration of 20 mg/L and initial AR1 dye concentration of 50 mg/L, an 8 mM H2O2 concentration, and a catalyst dose of 2 g/L, the maximum dye removal efficiency reached 96.5 % and 98 % respectively, while the total organic carbon (TOC) removal efficiency reached 68.5 % and 75 % respectively. The observed reaction time under the given experimental conditions was 120 min. The thermal stability of the biochar catalyst was found to be excellent based on the Thermogravimetric analysis (TGA) and Differential Scanning Calorimeter (DSC) studies. The catalysts that were developed demonstrated remarkable durability and negligible leaching of iron, hence enabling their repeated usage in subsequent cycles. The findings of the investigation suggest that the primary mechanism responsible for the degradation of the dye was the surface-based heterogeneous Fenton activity. Additionally, the effect of adsorption on the elimination of colour under varying pH conditions was examined, which had a very low influence in dye degradation (<30 %). The conducted scavenging investigations in the research have indicated the major involvement of hydroxyl radicals (OH) in the degradation process, followed by surface-bound hydroxyl radicals (OHsurface), superoxide radicals (O2−) and ultimately by singlet oxygen radicals (1O2). The study's economic analysis demonstrated that using microwave mode of heating for catalyst synthesis is both green and cost-effective. This observation suggests the possibility of practical implications in the domain of dye degradation.

Electrolytic synthesis of γ-Al2O3 nanoparticle from aluminum scrap for enhanced methylene blue adsorption: experimental and RSM modeling

The presence of methylene blue (MB) dye in wastewater has raised concern about human health and environmental ecology due to potential carcinogenic, and mutagenic effects. Therefore, this work aims to remove MB dye from wastewater using γ-Al2O3 nanoparticles synthesized from aluminum scrap via simple electrolytic method. The successful synthesis of the adsorbent was confirmed by a range of spectroscopy and microscopy techniques, including XRD, SEM, FTIR, and BET. The central composite design (CCD) of the response surface methodology (RSM) method was used to optimize the processing parameters such as solution pH, contact time, initial MB concentration, and adsorbent dose. The ANOVA results clearly shows that the quadratic model (p < 0.0001) was sufficient to the best predicting of the removal performance of MB dye (R2 = 0.9862). The optimum condition for the maximum MB dye removal (98.91%) was achieved at solution pH of 8.298, initial MB concentration of 31.657 mg/L, adsorbent dose of 0.387 g/L, and contact time of 46.728 min. Nano-γ-Al2O3 was shown to have a good surface area of 59 mg2/g by BET analysis. The adsorption kinetics follows the pseudo-second-order model (R2 = 0.997). With a maximum adsorption capacity of 137.17 mg/g, the Langmuir isotherm model (R2 = 984) provides the best fit to the adsorption isotherm data, indicating a monolayer adsorption process. Furthermore, thermodynamic analysis demonstrated that the adsorption of MB dye was an endothermic and spontaneous process. The reusability study showed that γ-Al2O3 nano-adsorbent retained 85.08% of its original removal efficiency after five cycles. According to the findings of the study, MB dye molecules were taken up by γ-Al2O3 nano-adsorbent via hydrogen bond formation, Van der Waals interaction, and electrostatic attraction. Therefore, γ-Al2O3 nanoparticles can be used as a potentially eco-friendly and low-cost adsorbent for the removal of MB dye from aqueous solutions.