Initial Methylene Blue Concentration Research Articles

Rational Engineering of Nanostructured NiS/GO/PVA for Efficient Photocatalytic Degradation of Organic Pollutants

A novel nanocomposite film synthesized from an inexpensive and easily accessible polymer such as poly (vinyl alcohol) (PVA), which is coated with nickel sulfide (NiS) and graphene oxide (GO), was obtained from used drinking-water bottles. The produced coated film was examined as a potential photocatalyst film for wastewater treatment promotion in a batch system for the removal of methylene blue (MB) and tetracycline (TC) antibiotics. The experimental results show that the presence of GO significantly increases the photocatalytic efficiency of NiS, and the MB and TC degradation results proved that the incorporation of GO with NiS led to a more than one-and-a-half-fold increase in the removal percentage in comparison with the NiS/PVA-coated film. After 30 min of illumination using GO/NiS/PVA-coated film, the removal efficiency reached 86% for MB and 64% for TC. The photodegradation kinetic rate followed the pseudo-first-order rate. Furthermore, the response surface methodology (RSM) model was utilized to study and optimize several operating parameters. The ideal circumstances to achieve 91% elimination of MB are 12 mg L−1 MB initial concentration, two lamps, and an illumination time of 15 min; however, to achieve 85% TC removal, 11 mg L−1 TC initial concentration, two lamps, and a 45 min illumination time should be used. The fabricated nanocomposite photocatalyst film seems to have promise for use in water purification systems.

Adsorption properties of methylene blue and Cu(II) on magnetically oxidized tannic acid cross-linked carboxymethyl chitosan gels

In this work, tannic acid was selected as a green cross-linking agent to cross-link carboxymethyl chitosan to prepare a magnetic adsorbent (CC-OTA@Fe3O4), which was used to remove methylene blue (MB) and Cu2+. CC-OTA@Fe3O4 was characterized by FTIR, 13C NMR, XRD, VSM, TGA, BET and SEM. The adsorption behavior was studied using various parameters such as pH value, contact time, initial concentration of MB and Cu2+, and temperature. The results showed that adsorption of MB and Cu2+ followed the pseudo-second-order model and the Sips model. The maximum adsorption capacities were determined to be 560.92 and 104.25 mg/g MB and Cu2+ at 298 K, respectively. Thermodynamic analysis showed that the adsorption is spontaneous and endothermic in nature. According to the results of FTIR and XPS analyses, the electrostatic interaction was accompanied by π–π interaction and hydrogen bonding for MB adsorption, while complexation and electrostatic interaction were the predominant mechanism for Cu2+ adsorption. Furthermore, CC-OTA@Fe3O4 displayed remarkable stability in 0.1 M HNO3, exhibited promising recyclability, and could be easily separated from aqueous solutions in the magnetic field. This study demonstrates the potential of CC-OTA@Fe3O4 as an adsorbent for the removal of cationic dyes and heavy metals from wastewater.

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.

Adsorption studies of methylene blue on cation-modified graphene oxide and graphene oxide/MXene membranes

Membranes prepared from graphene oxide (GO) have greater advantages over traditional materials for water treatment, while MXene is a good candidate for pollutant removal. However, the effect of different cations introduced into the prepared GO membranes on their adsorption performance must be further explored. In this study, a series of cation-modified GO and GO/MXene membranes were prepared based on the self-assembly of GO. Na+-modified membranes were found to be more effective at removing methylene blue (MB) than multivalent cation-modified GO membranes. However, the cation-modified GO/MXene membranes improved the MB adsorption efficiency, and the higher the ionic valence, the more pronounced the effect. In addition, the effects of the pH, temperature, contact time and initial concentration of MB on the adsorption performance of the membranes were investigated. The best removal of MB was achieved under neutral conditions, and the adsorption process was consistent with quasi-secondary kinetics and Langmuir isotherm models. The fitting results of the Langmuir isotherm model showed that the maximum adsorption capacities of the cation-modified GO membranes for MB were 654.9, 319.8, and 246.3 mg/g, respectively. The maximum adsorption capacities of the cation-modified GO/MXene membranes for MB were 687.3, 497.6, and 772.4 mg/g, respectively. Furthermore, the results of the intraparticle diffusion model revealed that the entire adsorption process was controlled by both external and internal diffusion. The thermodynamic analysis results indicated that the entire adsorption process was a heat-absorbing process and could proceed spontaneously. That the findings suggest that the Na+-modified GO and Al3+-modified GO/MXene membranes demonstrate the best adsorption effects and are promising adsorbents for MB removal.

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.

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.

Experimental study of methylene blue adsorption from aqueous solutions onto natural Algerian goethite

ABSTRACT The objective of this work is to study and model the methylene blue (MB) sorption, from aqueous solutions by goethite. The equilibrium time was reached during 10 min of agitation with 26.21 ℅ efficiency. MB removal efficiency is improved with an increased absorbent dose (0.5–08 g/L) for an initial 10 mg/L concentration. Treatment efficiency decreases with the increase of initial MB concentration (2–100 mg/L). The best adsorption yields were obtained in basic media. MB sorption kinetics via goethite leads to several results as to mechanisms that govern kinetics and isotherms equilibrium: Blanchard's model provides a better fit of the experimental results compared to Lagergren's model. Thus, the MB sorption kinetics is described by the pseudo-second order. Particle diffusion is involved in the MB removal mechanism, but it is not the only limiting step and the Boyd model application confirms that diffusion in the pores is the limiting step of the MB sorption process. The Elovich model is well verified and translated probably the existence of chemical-type interactions between MB and goethite. The study of MB adsorption isotherms showed that Freundlich, Temkin, and Elovich models are the best adapted than the Langmuir model. Finally, we can assess that goethite can be an interesting natural adsorbent for MB elimination from polluted waters in basic environments.

Sustainable removal of methylene blue dye from textile effluents by magnetized Tea waste and Peanut shells

Methylene blue finds numerous applications across various industries but its prolonged exposure to living organisms can result in significant health risks. In this study, the adsorption of magnetized Peanut shells and Tea waste for methylene blue dye removal has been reported. The biosorbents were synthesized by co-precipitation method and their suitability for methylene blue adsorption was confirmed through characterization techniques including Scanning Electron Microscope, Fourier Transfer Infrared Spectroscopy and X-Ray Diffraction analysis. After optimizing for pH (8.0), temperature (312 k), biosorbents dosage 25 mg/L with contact periods (35 min for Tea waste@Fe3O4 and 40 min for Peanut shells@Fe3O4), and initial methylene blue concentrations (5 ppm), the removal percentages of 95.88 % for Tea waste@Fe3O4 and 84.11 % for Peanut shells@Fe3O4 were achieved effectively. The equilibrium data for MB dye adsorption fitted well with the Langmuir model (R2 = 0.99) for Tea waste@Fe3O4 which indicated the formation of monolayer formation of adsorbate at the surface of adsorbent and the Freundlich model (R2 = 0.98) for Peanut shells@Fe3O4 confirmed the multilayers formation of MB dye at the material surface. Kinetic studies specified that both Tea waste@Fe3O4 (R2 = 0.99) and Peanut shells@Fe3O4 (R2 = 0.99) followed the pseudo-second order. Thermodynamic analysis showed that the adsorption process on Tea waste@Fe3O4 and Peanut shells@Fe3O4 was spontaneous (−ΔG) and endothermic. Tea waste@Fe3O4 exhibited ΔH (27.97 kJ/mol) and entropy ΔS (93.69 kJ/mol) while ΔH = 208.9 kJ/mol and ΔS 62 kJ/mol were found for Peanut shells@Fe3O4. The performance of the proposed biosorbent in industrial effluent demonstrated their effectiveness, highlighting their potential as a cost effective and sustainable solution for wastewater treatment.

Preparation of graphene from polyethylene terephthalate (PET) bottle wastes and its use for the removal of Methylene blue from aqueous solution

We present a method to produce graphene flakes (GFs) from polyethylene terephthalate (PET) bottle wastes by the pyrolysis method using modified bentonite as a catalyst. The as-synthesized GFs are analyzed in terms of crystal phase, morphology, and surface chemistry. The synthesized GFs have a porous, thin, and leaf-like morphology with a length ranging from a few hundred nanometers to a few tens of micrometers. The XRD and FT-IR results confirm the graphitization of PET and the presence of oxygen-containing functional groups on the surface of synthesized GFs. The obtained GFs are used as adsorbents for the removal of methylene blue (MB) from aqueous solution. The effects of various factors including, contact time, pH, and initial MB concentration, on the MB removal efficiency are examined. In addition, the adsorption isotherm models of Langmuir and Freundlich are studied. The best-fitting model is observed with the Freundlich isotherm model.

Photodegradation, kinetics and non-linear error functions of methylene blue dye using SrZrO3 perovskite photocatalyst

The degradation of methylene blue dye-contaminated wastewater via photocatalysis is an efficient approach towards environmental remediation. The SrZrO3 perovskite photocatalyst was synthesized using the modified Pechini sol-gel method, and characterized using XRD, FESEM, FTIR, and UV–visible spectrophotometer. Crystallite size obtained by the Scherrer and Williamson-Hall methods were 45.56 and 44.50 nm, respectively. The sample exhibited an orthorhombic crystal structure. The optical bandgap was estimated to be 5.31 eV. Kinetic study for the degradation of methylene blue dye using SrZrO3 in the presence of H2O2 showed complete decontamination of the methylene blue dye in the time interval of 90–120 min under visible light irradiation. The degradation efficiency was above 80.1 % under illumination and less than 40.1 % in dark. Kinetic studies were performed by varying the dose of photocatalyst and initial concentration of methylene blue. It was observed that higher dose of the photocatalyst and lower concentration of the contaminant produced higher rate of degradation. The solution pH 3 and catalysts dosage of 200 mg yielded the highest rate of degradation. The experimental data fitted best into the Psuedosecond order kinetic model with the highest R2 value, indicating a strong linear relationship. The experimental data was subjected into nonlinear error functions, where the Psuedo-second order kinetic model demonstrated lower values of error functions. The results suggest that the prepared SrZrO3 photocatalyst coupled H2O2 is a promising photocatalyst for the decontamination of methylene blue dye under visible light irradiation.

Superabsorbent ZnO/rubber-based hydrogel composite for removal and photocatalytic degradation of methylene blue

A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50 wt%. An NR/PAA hydrogel containing 40 wt% of NR (NR-40) had a water absorption capacity of 214 g/g (21,400 %) of its dry weight. The compressive modulus increased 512 % and sample integrity was improved due to the physical entanglement of NR chains. NR-40 hydrogel removed 97 % of methylene blue (MB) from the aqueous solution in 1 h (at initial concentrations of 10–1000 mg/L) and produced a maximum removal of 1191 mg MB/g of hydrogel at an initial MB concentration of 4500 mg/L. The adsorption of MB was an endothermic process. Fourier transform infrared spectroscopy indicated that hydrogen bonding and electrostatic interaction drove the process. After the in-situ incorporation of ZnO into NR-40, absorbed energy from sunlight generated active species that could photocatalytically degrade adsorbed MB in the hydrogel matrix. The scavenger tests indicated that superoxide radical anions and hydroxyl radicals were the main species for this process. The hydrogel composite material showed good stability and could be regenerated and reused over 10 cycles, degrading >80 % of the adsorbed dye. This novel natural-based hydrogel provides double functions of adsorption and photodegradation of toxic dyes without the requirement of chemicals and a separation process.

Exploring the sustainable elimination of dye using cellulose nanofibrils- vinyl resin based nanofiltration membranes

This study focuses on the development of a novel self-cleaning nanofiltration membrane for the efficient removal of the cationic dye methylene blue (MB) from industrial wastewater. The membrane is composed of vinyl resin (VR), cellulose nanofibrils (CNF), and titanium alpha aluminate (TAAL) nanoparticles.The TAAL loading ranged from 1 to 5 wt%, the pH varied from 5 to 10, and the initial MB concentration ranged from 10 to 50 ppm. Using a dead-end filtration system, the (VR/CNF@TAAL) membrane with 5 wt% TAAL at pH 10 demonstrated excellent performances. It achieved a remarkable 98.6% removal efficiency for 30 ppm MB dye, with a maximum adsorption capacity of 125.8 mg/g. The adsorption kinetics analysis revealed that the process followed the pseudo-second-order model, indicating a chemisorption mechanism. The rate constant was determined to be 1.2732 × 10–3 g mg−1 min−1. The Freundlich isotherm model provided a better fit (R2 = 0.996) than the Langmuir model, suggesting multilayer adsorption on the nanocomposite membrane surface. In addition to its high adsorption and filtration capabilities, the (VR/CNF@TAAL) nanocomposite membrane exhibited cost-effectiveness and environmental friendliness as an adsorbent for MB removal from industrial wastewater. The membrane’s self-cleaning property further contributes to sustainability by reducing the need for additional chemical treatments.

Studying the kinetics and removal mechanism of the methylene blue dye in a continuous adsorption process using prepared mesoporous materials

ABSTRACT This study investigated the removal of a typical organic pollutant methylene blue (MB) dye from wastewater by a prepared mesoporous SBA-15 adsorbent in a continuous adsorption system (fixed-bed column). The structural and textural properties of the SBA-15 adsorbent were determined using different characterization techniques. The adsorption of continuous system experiments assessed the bed height effect, initial concentration, and flow rate on a breakthrough curve. The kinetic constants and breakthrough curves were obtained using the Thomas and Yan models. The breakthrough results revealed that SBA-15 has an excellent adsorption efficiency for use in the continuous adsorption system. The findings explain that MB removal achieved the maximum uptake (84 mg/g) at 6 cm of bed height, 0.5 mL/min of flow rate, and 30 mg/L initial concentration of MB. SBA-15 can be efficiently regenerated by calcination and re-employed 5 times in a fixed-bed system without a significant loss in its adsorption capacity of MB from MB solutions. As a result, SBA-15 was determined as the appropriate media to be adsorbent for MB. This study suggests that the prepared SBA-15 is feasible to use effectively for MB removal from the wastewater.

Facile Fabrication of Hydroxyapatite and Bentonite Encapsulated Biopolymeric Hybrid Composites for Selective Removal of Methylene Blue

AbstractDyeing industries release their hazardous dyeing effluents into the environment which affects the human health and ecosystem. Hence, the removal of dye from waste‐water is mandatory one. In this present study, focus on the fabrication of bio‐clay‐ceramic hybrid composites by dispersing bentonite (BT) clay and ceramic hydroxyapatite (HA) into alginate (Alg) and gelatin (Gel) polymeric matrixes by in‐situ method which gives BTHAAlg and BTHAGel hybrid composites for methylene blue (MB) removal. The various adsorption influencing parameters such as shaking time, adsorbent dosage, pH and initial MB concentration were optimized under batch method. The highest MB adsorption capacities of BTHAAlg and BTHAGel composites were found to be 43.70 and 47.50 mg/g respectively with optimized conditions of 100 mg/L of initial MB concentration, 40 min shaking time and 0.1 g dosages. In pH studies, the high MB adsorption capacity of bio‐clay‐ceramic composites were noticed at pH 11. The characterization techniques like FTIR, SEM and EDAX analysis were performed to find the physico‐chemical properties of bio‐clay‐ceramic composites. The equilibrium data of hybrid composites towards MB adsorption was well fitted with Langmuir isotherm model than D‐R and Fruendlich models because of higher r and low sd values. The negative values of ▵Go at three different temperatures (303, 313 and 323 K) indicate that the spontaneous nature of MB adsorption, while positive values of ΔHo and ΔSo revealed that the MB adsorption onto hybrid composites was endothermic in nature and more randomness occurred at solid/liquid interfaces. In kinetic studies, the MB adsorption onto hybrid composites was well fitted with pseudo‐second‐order and intra‐particle diffusion models. The electrostatic attraction and hydrogen bonding plays a dominant role in MB adsorption onto BTHAAlg and BTHAGel bio‐clay‐ceramic composites. The regeneration studies proposed that the hybrid composites can be reusable upto five cycles. Hence, the developed bio‐clay‐ceramic hybrid composites were act as best adsorbents for MB removal.

Synthesis and characterization of mesoporous caged silica for efficient adsorption of methylene blue from aqueous solution

Addressing the challenge of removing dyes from textile industry wastewater is crucial for wastewater treatment. Adsorption, utilizing suitable materials, emerges as a promising solution. This work introduces caged silica as an effective adsorption material for wastewater treatment in the textile industry. The proposed caged silica was synthesized via the hard template synthesis method, commonly used in various applications such as catalysts and wastewater treatment. Caged silica exhibited an amorphous structure with notable BET surface area (448m2/g), pore volume (0.325cm3/g), and average pore size (2.4nm), confirmed through detailed characterization. Evaluation of its adsorption capacity for methylene blue (MB) revealed an impressive removal efficiency of approximately 95% within the initial 20 min. The adsorption process followed the pseudo-second-order model and adhered more closely to the Freundlich isotherm model than the Langmuir model. Additionally, the study investigates the effects of pH, percent removal efficiency, cyclic stability, and initial MB concentration on the adsorption procedure. Consequently, the synthesized caged silica stands out as a promising mesoporous material for efficiently removing MB from aqueous solutions, offering practical application potential in wastewater treatment.

Catalytic Activity of CuO-bentonite Bead for the Removal of Methylene Blue by Fenton like Process

Non-biodegradable dyes, potentially contaminate the water and poses serious risk to the environment. So their removal requires alarming attention. The formation of CuO-bentonite bead and their dye removal application is the main focus of the current investigation. X-ray diffraction spectroscopy (XRD), Field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray spectroscopy (EDS) analysis were implemented to evaluate the crystalline structure and morphology of the prepared sample. The catalytic activity of the CuO-bentonite bead was studied against the dye methylene blue (MB) by an advanced oxidation process like Fenton. The experimental data shows a maximum 94.08 % of the dye removal capacity of the beads in just 20 minutes. Further, for the detail dye removal study optimum environments such as initial MB concentration, pH range, and oxidant dosage were altered during the reaction. Additionally, the CuO-bentonite bead showed 89.03 % dye removal even after five reuse cycles; which exhibits the heightened stability and robustness of the CuO-bentonite bead as a catalyst. Therefore, this simply prepared CuO-bentonite bead revealed a new approach to wastewater treatment.

NiTiO3 nanoparticles: An environmental game changer in electro-Fenton wastewater remediation

BackgroundIn the face of escalating water pollution challenges, the study explores the efficacy of Electro-Fenton (EF) treatment using NiTiO3 perovskite-modified cathodes for methylene blue (MB) removal from wastewater. MethodsEmploying a Central Composite Design (CCD) methodology, significant factors influencing the EF process, including initial MB concentration, pH, applied current, and reaction time, were optimized. The NiTiO3 catalyst was meticulously characterized, revealing its rhombohedral crystal structure, uniform particle distribution, and efficient charge transfer properties. FindingsElectrochemical analyses demonstrated the superior performance of the NiTiO3/Graphite electrode, emphasizing its increased electroactive sites, enhanced oxygen reduction capability, and reduced charge transfer resistance compared to the bare Graphite electrode. The EF process was finely tuned, demonstrating a 95.38 % removal efficiency of MB at optimal conditions (initial concentration: 25 mg L−1, pH: 4.5, current: 40 mA, time: 110 min). This study underscores the promising potential of NiTiO3-modified cathodes in advanced water treatment applications, highlighting their robust efficiency and environmental significance in combating persistent organic pollutants.

High-efficient removal of methylene blue by zirconium-based organic frameworks modified with 1,3,5-benzenetricarboxylic acid: Characterization, performances, and mechanisms

The vast discharge of methylene blue (MB) dye in industrial effluent, risks the ecological environment, thus making its removal unavoidable. Recently, metal organic frameworks (MOFs) due to their larger pore volume, surface area and easy synthesis have proved to be exceptionally promising materials for contaminant treatment. Based on 1,3,5-benzenetricarboxylic acid (BTC) as a modifier, a new composite material consisting of BTC and Zr-based MOF (UIO-66-BTC) was fabricated for the effective removal of MB from the effluent. Its synthesis and efficient application has been confirmed by characterization analysis. The influencing factors, adsorption isotherms, and adsorption kinetics of MB adsorption by adsorbent were studied. It was demonstrated that the removal rate of MB adsorption by UIO-66-BTC reached 98.45% and the adsorption amount reached 393.80 mg g−1 at temperature (298 K), pH 7, adsorbent dosage (0.5 g L−1), MB initial concentration (200 mg L−1), and contact time of 720 min, respectively. The maximum adsorption of MB by UIO-66-BTC was 20.827 times higher than that of UIO-66 (18.908 mg g−1). The experimental data fits with the pseudo-second-order kinetic model and Langmuir isotherm, implying that the adsorption process is a monolayer chemisorption process. The thermodynamic and regeneration experiments showed that the spontaneous process enhanced the adsorption of MB at lower temperatures and the adsorption efficiency of MB remained above 68% after five successive cycles. The mechanism of MB adsorption on adsorbents is mainly based on electrostatic interactions, pore filling, hydrogen bonding and π-π interactions. It is concluded that this new adsorbent can be effectively used to treat MB in effluents.

Carrageenan/calcium alginate composite hydrogel filtration membranes for efficient cationic dye separation

The development of biopolymer-based filtration systems for water remediation applications is an extremely fascinating area of research. In this paper, we developed a biopolymer-based filtration system using sodium alginate (NaAlg) and carrageenan (Car) for the removal of the toxic cationic dye, methylene blue (MB). The membrane's properties were assessed using FTIR, TGA, UTM, FESEM, EDS, XRD, and water uptake, revealing commendable thermomechanical stability (5.79 MPa), good hydrophilicity, and compatibility. The experimental results further revealed that lambda Car/calcium alginate (λ-Car/CaAlg) exhibited superior dye rejection (100%) and flux (11.67 L m−2 h−1) compared to kappa Car/CaAlg (κ-Car/CaAlg) (99.22% and 11.19 L m−2 h−1) and plain alginate (CaAlg) (99.63% and 9.79 L m−2 h−1). The high MB rejection rate was attributed to the sieving mechanism and electrostatic interaction. A rejection rate of 100% was achieved at an initial MB concentration of 10 mg/L, pressure of 0.1 MPa, pH of 7, and temperature of 25°C. Furthermore, the hydrogel membranes demonstrated excellent recyclability over nine cycles, indicating their potential for water treatment applications.