Adsorption Of Methylene Blue Dye Research Articles

Production and Characterization of Activated Carbon Derived from Costus Afer Leaves (C. afer) for the Adsorption of Methylene Blue Dye from an Aqueous Solution

Production and Characterization of Activated Carbon Derived from Costus Afer Leaves (C. afer) for the Adsorption of Methylene Blue Dye from an Aqueous Solution

Optimization of Methylene Blue Dye Adsorption onto Coconut Husk Cellulose Using Response Surface Methodology: Adsorption Kinetics, Isotherms and Reusability Studies

Optimization of Methylene Blue Dye Adsorption onto Coconut Husk Cellulose Using Response Surface Methodology: Adsorption Kinetics, Isotherms and Reusability Studies

Synthesis of pumice and medical waste incinerator fly ash based phosphate geopolymers for methylene blue dye adsorption: co-valorization, parameters and mechanism

Synthesis of pumice-based geopolymer composites, GP-0, GP-10, GP-20 and GP-30, substituted with fractions of 0, 10, 20 and 30% by weight of medical waste incinerator fly ash (MWI-FA), respectively and application for dye removal.

Investigation of methylene blue dye adsorption on nanographite oxide prepared by electrochemical exfoliation

The adsorption properties of nanographite oxide (NGO) prepared by electrochemical exfoliation have been explored using methylene blue (MB) dye. It has been found that NGO adsorbs MB molecules through π–π interaction and proton transfer from the carboxyl group of NGO to the MB molecule. It has been proved that the adsorption process obeys the Freundlich isotherm model and the pseudo-second-order kinetic model, the thermodynamic parameters of which indicate that the process occurs spontaneously, while achieving a dye removal rate of 75 to 98% with a final dye concentration of only 0.005 mg dm−3.

Application for fitting of Langmuir and Freundlich equations Studies on the experminatl data of adsorption of Methylene Blue Dye by Cobalt Oxide Surface

This study is based on the investigation of the adsorption property of Methylene blue onto Co3O4 as a surface. the optimum conditions of this study were determind and it was found that the dose of Co3O4 was 50 mg, the pH of adsorption dye was 10, the initial concentration of dye was 15 mg/L, and temperature found to be 45 C°. Langmuir and Freundlich isotherm models were used for investigating the equilibrium adsorption of Methylene blue dye onto Co3O4 . The thermodynamic study shows that the adsorption of the MB dye process was non-spontaneous and endothermic under the studied conditions.

Enhanced sensing performance of carboxymethyl cellulose sodium to hydrogen sulphide gas and methylene blue dye by constructing CuO@ZnO core/shell heterostructure: A DFT/TD-DFT study

Anthropogenic air and water pollution are two of the world's most serious public health threats, causing around 9 million fatalities each year. Accordingly, CuO, ZnO, and CuO@ZnO core/shell structures were optimized utilizing the time-dependent density functional theory (TD-DFT) method to study the effect of CuO@ZnO core/shell on the sensitivity of carboxymethyl cellulose sodium (CMC). Absorption spectra and optical band gap (Eg) have been investigated utilizing the TD-DFT method. The calculated Eg values for CuO and ZnO equal 1.23 and 3.29 eV, respectively, which agree well with those reported in the literature. The effects of H2S gas and methylene blue dye (MB) adsorption on the electronic characteristics of dimer CMC /CuO@ZnO structures were investigated in terms of TDM, HOMO/LUMO energy, and molecular electrostatic potential (MESP). The TDM in dimer CMC/CuO@ZnO structure was increased to 72.152 and 67.606 Debye, while ΔE was reduced by 6.42% and 82.57% due to the adsorption of H2S and MB dye, respectively. This means that it has a faster response to MB than to H2S. Additionally, MESP confirms the increased reactivity of dimer CMC/CuO@ZnO due to the adsorption process. As a result, dimer CMC/CuO@ZnO structures appear to be attractive candidates for H2S and MB dye sensing applications.

Synergistic effect of adsorption and photo-catalysis on the removal of hazardous dyes using steam exploded banana fiber derived micro-cellulose

The utilization of banana fiber derived from micro-cellulose (MC) was exploited as a supporting material for advanced oxidation process (AOP) on the degradation of methylene blue and methyl violet dyes in the presence of H2O2-UV in aqueous medium for the first time using green chemistry protocols. Additionally, it was also effectively utilized for the adsorption of methylene blue dye using addition of H2O2 in the presence of sunlight. The MC powder was fabricated using an acid alkali process from the pseudo-stem of a banana tree. The as-fabricated MC powder was systematically characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrometer (EDX), and zero point charge (pHzpc). The AOP assisted degradation of dye molecules was monitored by using calorimetric techniques as a function of dye concentration and pH in a batch reactor. In a short period of time, the maximum degradation efficiency of 98 % of methylene blue was achieved using MC powder assisted H2O2 under UV irradiation at a minimum irradiation time of 120 min at pH 7.0 using dosage of 0.2 g/L. However, in the absence of UV light, the degradation efficiency of MC powder assisted H2O2 was only about 5–10 % without UV light irradiation. The dye removal was studied as a function of various operational parameters such as pH (3–11), catalyst dose (0.2–0.6 g/L), and initial dye concentration (100–400 mg/L). In the presence of H2O2-sunlight and 0.2 g/L of dosage at pH 7.0 at a minimum contact time of 120 min, MC fiber showed maximum adsorption capacities of 98% and 85% for 100 mg/L and 400 mg/L of methylene blue concentrations. According to the obtained data, the adsorption of methylene blue dye on MC follows the Freundlich isotherm model (R2 = 0.9886) and pseudo-first-order kinetic model (R2 = 0.9596) due to the higher regression coefficients. This process of dye degradation and adsorption process is a novel one and environmentally benign for an effective removal of hazardous dyes.

Efficient Adsorptive Removal of Methylene Blue Dye from Aqueous Solution Using Eragrostis Teff Biomass-Derived Nitrogen and Phosphorus-Codoped Carbon Quantum Dots.

Carbon quantum dots have a great application potential in environmental protection via adsorption technology due to their large specific surface area and negative zeta potential. In this work, nitrogen and phosphorus-codoped carbon quantum dots (NP-CQDs) with a large specific surface area and negative zeta potential were successfully synthesized by a single-step hydrothermal synthesis. Batch adsorption studies were utilized to assess the adsorbent's capacity to remove common methylene blue (MB) dye contaminants from an aqueous solution. The experiment showed that MB dye could be removed in 30 min under optimum experimental conditions, with a removal efficiency of 93.73%. The adsorbent's large surface area of 526.063 m2/g and negative zeta potential of -12.3 mV contribute to the high removal efficiency. The Freundlich isotherm model fits the adsorption process well at 298 K, with R2 and n values of 0.99678 and 4.564, respectively, indicating its applicability. A kinetic study demonstrated that the pseudo-second-order model, rather than the pseudo-first-order model, is more suited to represent the process of MB dye adsorption onto NP-CQDs. This research established a simple and cost-effective method for developing a highly efficient NP-CQD adsorbent for organic dye degradation by adsorption.

Selective separation of methylene blue from aqueous solution using Mn/Pd decorated chemically modified MoS2 nanocomposites

The presence of dyes in wastewater is posing as serious threat to human health. There are a huge number of physical, chemical, biological and hybrid methods available for the removal of colorants (dyes) from aqueous environment. In this work, we demonstrate the fabrication of new nanocomposites, MoS2-COOH/gly@M (M= Mn, Pd), with high adsorption property fabricated by chemically immobilizing manganese and palladium metallic centers onto the glycine- modified molybdenum disulfide (MoS2) material. The chemical and physical properties of adsorbents were analyzed using Fourier transform infrared spectrometer (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) companied by energy dispersive X-ray and mapping (EDAX & MAP) analyses. Zeta potential (ξ) technique was also used to measure the surface charge of adsorbents. Performances of nanocomposites were investigated on the sewage as adsorbent for dye removal. Synthesized nanocomposites revealed selective adsorption of methylene blue (MB) dye from aqueous mixture of MB and methyl orange (MO). Results displayed the equivalent high adsorption capacity for MB and MO up to 553 and 619 mg/g, respectively (green reaction condition= 120 min contact time, ,25 °C, pH 2.0 and pH 7.0, in the presence of 2 mg adsorbent and 50 mg/L (30 mL) initial concentration of MO and MB). The remarkable adsorption capacity of dye by MoS2-COOH/gly@M (M= Mn, Pd) nanocomposites can be attributed to the intermolecular interactions due to the presence of the amine, hydroxyl, and carboxyl functionalities. To describe the adsorption mechanism of MO and MB dye by synthesized nanomaterials, the pseudo-first-order and pseudo-second-order kinetics were further studied. Isotherm models displayed that the adsorption of MB and MO onto the MoS2-COOH/gly@M (M= Mn, Pd) nanocomposites is more correspondent with the Freundlich model with high-correlation coefficients. The results showed that the electrostatic attraction and H-bonding interaction were the basic cause of the adsorption of these anionic and cationic dyes on the surface of the nanocomposites. One of the distinguished properties of adsorbents is their capability to selectively adsorb MB from an admixture of MO and MB. The adsorption selectively has expanded in the following order: MoS2 < MoS2-COOH/gly@Mn < MoS2-COOH/gly@Pd. Based on the results, this new type of nanocomposites has potential to act as an effective and affordable adsorbent material for dye removal from an industrial sewage.

CuS/Cellulose acetate nanofiber composite: A study on adsorption and photocatalytic activity for water remediation

This paper addresses the pressing concern of environmental deterioration by investigating innovative solutions for tackling water pollution in aquatic ecosystems. Various hazardous pollutants, such as dyes, pharmaceuticals, heavy metals, and pesticides, pose significant threats to both the environment and human health. To combat these issues, in this work we explored the synthesis of composite nanofibers using copper sulfide (CuS) nanoparticles and cellulose acetate (AC) polymer matrix through a gas-liquid sulfurization process. The resulting nanocomposites were used to fabricate nanofibers by the electrospinning technique. The morphological analyses revealed a transition from ribbon-like structures to cylindrical forms as nanoparticle concentration was increased. Chemical analysis confirmed the presence of CuS nanoparticles within the composite nanofibers. XRD studies indicated a covellite crystal structure of the CuS nanoparticles. TGA analysis revealed a coordination complex formation between nanoparticles and dimethylformamide. Optical properties showed variations in band gap energies, from 1.76 to 1.9 eV, as nanoparticle concentration changed. Photocatalysis studies demonstrated that the composite nanofibers exhibited enhanced adsorption and degradation of methylene blue dye under solar irradiation. Overall, this study contributes to understanding the potential application of CuS/AC composite nanofibers for environmental remediation.

Reshaping environmental sustainability: Poultry by-products digestate valorization for enhanced biochar performance in methylene blue removal

Anaerobic digestion is a highly effective and innovative method for treating organic waste while simultaneously generating energy. However, the treatment of the resulting digestate remains a challenging endeavor. To address this issue, poultry by-products digestate is used in this study to prepare biochars at two different pyrolysis temperatures (500/600 °C). Despite their potential, the utilization of untreated biochar is restricted due to its inadequate adsorption capacity. Therefore, each biochar was chemically activated using either HNO3 or KOH to synthesize four activated biochars (BC5@KOH, BC6@HNO3, BC5@HNO3, and BC6@HNO3). The aim is to investigate how the nature of chemical activation and pyrolysis temperature influence the adsorption of methylene blue dye. Characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), Raman analysis, and pHpzc determination, were exploited to comprehensively elucidate the structure and composition of both unprocessed and chemically activated biochars. Among the activated biochars, the adsorbent BC5@HNO3 exhibits the highest methylene blue (MB) adsorption capacity, reaching 101.72 mg.g−1 at 298 K under (pH = 2, ads dose = 0.6 g.L−1, shaking time of 20 min, as optimal conditions for MB adsorption. Adsorption data for each adsorbent strongly aligns with both the Langmuir isotherm model and the pseudo-second-order kinetic model. Moreover, the thermodynamic study reveals that the adsorption process was endothermic and spontaneous. The adsorption mechanism of MB dye was explored using various analytical techniques, including FTIR, SEM, PZC, and pH impact assessment. The findings suggest correlations with electrostatic interactions, hydrogen bonding, pore filling, as well as n-π and π-π interactions. Apparently, activated biochars play a crucial role in efficiently removing methylene blue dye, showcasing their potential as environmentally friendly and effective adsorbents.

Preparation and Characterization of Fe3O4/Poly(HEMA-co-IA) Magnetic Hydrogels for Removal of Methylene Blue from Aqueous Solution.

In the present study, Fe3O4/poly(2-hydroxyethyl methacrylate-co-itaconic acid) magnetic hydrogels (MHGs) were prepared by in situ synthesis of Fe3O4 magnetic particles in hydrogels (HGs). The resulting magnetic hydrogels were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), a vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and N2 adsorption-desorption. The effect of Fe3O4 on the swelling behavior and adsorption of methylene blue (MB) dye of the prepared hydrogel was studied. Parameters such as the dose, pH, contact time, and MB initial concentration were investigated. The results show that 75% (HG) and 91% (MHG) of MB (200 mg/L) were removed at doses of 2 mg/mL and 1 mg/mL, respectively, under a pH of 6.8 and a contact time of 10 min. The adsorption behavior followed the Langmuir isotherm model, indicating that the adsorption process takes place in monolayers and on homogeneous surfaces. The Langmuir capacities for MB adsorption using the HGs and MHGs were 78 and 174 mg/g, respectively. The adsorption kinetics followed a pseudo-second-order kinetic model. In addition, thermodynamic studies carried out show that the adsorption process is spontaneous and endothermic. Adsorption-desorption studies indicate that the magnetic hydrogel can remove MB for four cycles with removal efficiencies above 90%. Therefore, a MHG is suitable as an alternative material for MB adsorption.

Preparation and Upscaling of Zeolite@TiO2 Core‐shell for the Removal of Pb(II) and Methylene Blue Dye from Wastewater

AbstractThe present work reports the preparation and adsorption kinetics of a Zeolite@TiO2 multifunctional adsorbent for the removal of heavy metal (Pb(II)) and organic pollutants (methylene blue) from wastewater. The design of the material is a core‐shell having a porous core of zeolite and the surface is supported with the growth of nano TiO2 for a tunable surface and interface designing for efficient wastewater treatment. The formation of Zeolite@TiO2 core‐shell has been characterized by XRD, XPS, SEM, TEM, and DRS spectroscopic techniques. BET surface analysis indicated increased surface area for efficient adsorption. The design of multifunctional adsorbent acts as a charged crossing point for quick adsorption and breakdown of pollutants in water. The adsorption of Pb(II) and methylene blue (MB) dye follows the Freundlich adsorption isotherm confirming presence of multilayer of TiO2 in the adsorption process. Complete adsorption for Pb(II) is achieved in 25 minutes whereas MB dye is completely adsorbed within 15 minutes with high adsorption capacities. Photocatalytic degradation activity for MB dye were also analyzed and indicated 30 mg/l was degraded in 10 min. The DRS and photoluminescence life time study support good photocatalytic activity. The regeneration and recyclability of the core‐shell material have also been studied and reported.

Synthesis of CuO/CeO2 Nanocomposites for Adsorption and Efficient Photocatalytic Degradation of Methylene Blue Dye

Nanocomposites are composed of a wide range of systems, including 1-D, 2-D, 3-D, and unstructured substances, and are blended at nanometer sizes with very distinct constituents. Due to the presence of quantum confinement, surface Plasmon response, tunneling of electrons, and density of states, nanocomposites are superior materials that display unusual and distinctive features. Photocatalysts benefit from unique features offered by nanocomposites made of two or more semiconductors with differing band gaps. Due to their uses and possible threats to living things, dyes are considered the most significant water contaminants. Industrial effluent must be treated using powerful adsorbents and photocatalysts to remove dangerous chemical dyes from contaminated water sources. This paper employs a co-precipitation approach to create photocatalytic CeO2 nanoparticles and a CuO/CeO2 nanocomposite for the inexpensive removal of Methylene Blue (MB) from aqueous solution. In this approach, the dispersion of electrons and holes is induced by the absorption of visible light, leading to the breaking of water molecules into radicals. These radicals serve as agents for the degradation of dyes. Utilizing X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Ultra-Violet Visible spectroscopy (UV–Vis), and Fourier Transform Infrared spectroscopy (FTIR), the CuO/CeO2 nanocomposite has been characterized. The peaks in XRD suggest that the nanocomposite is most likely made up of the crystalline phases of CuO and CeO2. A sequence of smaller peaks and larger peaks are visible in the measured pattern, spanning the 20° to 40° 2θ range, indicating the presence of amorphous or loosely organized regions inside the material. The results of the FTIR study show that CuO and CeO2 phases are present in the nanocomposite simultaneously. The results further suggest that the CuO/CeO2 nanocomposite exhibits notable photocatalytic activity, successfully facilitating the decomposition of the reactants under UV-Vis light exposure for a certain period.

Brazilian palygorskite as an alternative to commercial adsorbents for methylene blue: A discussion about composition, morphology and pore profile

Palygorskite has attracted particular attention as a specialized adsorbent due to its high specific surface area, porous texture and abundant surface groups, but its processing for commercial products makes the resulting material more expensive. In this scope, the aim of this work is to evaluate the potential of Brazilian naturally occurring palygorskite samples with low processing degree as an alternative to commercial palygorskites adsorbents for methylene blue, evaluating samples with different compositions, morphologies and microporous profiles. Materials were characterized using FTIR, X-ray diffraction, X-ray fluorescence, scanning electron microscopy, and surface area analysis (BET method). The Brazilian ones were processed in bar and disk mills and passed through a # 325 mesh sieve system. All samples showed common palygorskite X-ray diffraction patterns and specific surface area ranging from 100 to 147 m2/g. The application of clay samples was investigated for the adsorption of methylene blue (MB) dye, and the influence time of adsorption, initial dye concentration and adsorbent dosage were evaluated. The methylene blue adsorption was best described by the pseudo-second order model. The adsorption kinetics of methylene blue by palygorskite conforms to the pseudo-second-order model (R2 = 0,9997). The maximum removal capacity for methylene blue was determined to be 694 (±36.53) mg/g. Additionally, the Freundlich model demonstrated the most favorable mathematical fit. Adsorption capacities varied between 49 and 150 mg/g for 300 mg/L MB solutions, with noteworthy performance exhibited by Brazilian samples, achieving up to twice the adsorption compared to their commercial counterparts, despite possessing lower specific surface areas. The presence of two distinct pore modes, centered at 25 and 45 Å, proved pivotal in the sample with the highest adsorption capacity, reaching adsorption equilibrium at 40 min.

Adsorption behavior and mechanism of modified Pinus massoniana pollen microcarriers for extremely efficient and rapid adsorption of cationic methylene blue dye

Herein, a novel biosorbent was successfully fabricated through a two-step process employing Pinus massoniana pollen as raw material. The efficacy of this biosorbent in eliminating methylene blue (MB), a typical organic cationic dye, from highly concentrated industrial wastewater was investigated. The results demonstrated that by adjusting the wettability of pollen microcarriers, it is possible to significantly increase their adsorption capacity for cationic dyes, resulting in a remarkable 25-fold improvement. The modified Pinus massoniana pollen microcarriers (MPPMC) exhibited an optimal adsorption capacity (585 mg/g) under specific conditions and a rapid equilibrium (97.6% in 5 min, uptake 487.8 mg/g) even at room temperature, showing excellent performance in removing MB efficiently and quickly. It is worth noting that the modified microcarriers could be regenerated via a simple pH-controlled adsorption-desorption cycle, maintaining their superior efficiency (> 99%) even after undergoing five cycles, indicating their excellent reproducibility. The MB adsorption process on MPPMC obeyed the pseudo-second-order kinetic model and followed the Langmuir model. Through the introduced modifications, the substantial deprotonation of carboxyl groups notably augmented electrostatic and hydrogen bonding interactions between MPPMC and MB. Overall, this study offers a sustainable, eco-friendly biological adsorbent, and the MPPMC exhibit the considerable potential for efficient and rapid removal of organic cationic dyes in wastewater.

PURIFICAÇÃO ÁCIDO-BASE EXPERIMENTAL DE CASCAS DE ARROZ CARBONIZADAS: EXPLORANDO SUA EFICÁCIA NA ADSORÇÃO DE RESÍDUOS NÃO VALORIZADOS DA INDÚSTRIA DE ARROZ

The burning of rice husks produces natural silica and generates charcoal with excellent properties for the adsorption of different pollutants. The objective of this study was to enhance the adsorption properties of this industrial residue from burning rice husk through acid and base purifications. The raw coal (RC) was initially modified with HCl(aq.) and then with NaOH(aq.), and subsequently renamed MC. Efficiency was verified by the adsorption of methylene blue (MB) dye, considering a concentration of 10 mg L-1, dosage of 0.05 g L-1, pH 6.7, and 120 min. MB removal was 78% for RC and 97% for MC, with experimental capacities of 144.78 mg g-1 and 180.78 mg g-1, respectively. The kinetics were better adjusted by Avrami (R2 0.99, error &lt;2.8%). The properties of charcoal improved with the modification, presenting a more porous structure, greater surface area and functional groups that contributed to adsorption, proving that simple purification methods, such as acid-base purification, can be crucial for waste reuse.&#x0D;

Design and synthesis of a new coordination polymer of zinc (II): Crystal structure and evaluation for its adsorption studies in removing perilous organic dye pollutants in aqueous medium

The contamination of aqueous environments by hazardous organic dye pollutants has become a pressing global concern, necessitating innovative strategies for effective water purification. In this research, we present the design, synthesis, and comprehensive evaluation of a new zinc(II) coordination polymer, formulated as [Zn(HIPA)(HIZ)2]n⋅H2O (CP-1), specifically tailored for adsorption studies aimed at the removal of hazardous organic dye pollutants from aqueous mediums. The CP-1 was effectively synthesized using a hydrothermal synthesis approach and incorporates two distinct organic ligands, namely, 5‑hydroxy isophthalic acid, and imidazole, along with a water molecule within the crystal lattice. The structural and morphological attributes of the synthesized coordination polymer (CP-1) are elucidated through a comprehensive characterization process, including SCXRD, PXRD, FTIR, UV–VIS spectroscopy, TGA, SEM, and BET analysis. Single-crystal diffraction of CP-1 confirms that Zn is coordinated in a tetrahedral environment. The CP-1 was systematically examined for dye adsorption of four hazardous organic dyes namely methylene blue (MB), methyl orange (MO), crystal violet (CV) and congo red (CR). Batch adsorption experiments were conducted, probing the influence of variables such as contact time, pH, temperature, the effect of dosage and initial dye concentration on the adsorption efficiency of CP-1. The CP-1 shows the best adsorption efficiency for MB followed by MO, CV, and CR. The CP-1 exhibits high selectivity and efficient MB and MO dyes adsorption at room temperature and neutral pH. Moreover, three different kinetic models were utilized to attain a deeper comprehension of the reaction mechanism involved in the adsorption of MB and MO. Amongst these models, the pseudo-second-order kinetic model demonstrated the best fit for both cases. Furthermore, the density functional theory with the dispersion correction (Grimme's DFT-D3) was utilized to support the dye's adsorption mechanism with the CP-1. To study this, the dispersion corrected interaction energies were computed for the dye-complex systems at B3LYP-D3/6–31G(d,p)/LANL2DZ level of theory. The efficient adsorption performance, coupled with its structural and chemical stability, suggests that CP-1 holds great potential for practical applications in water treatment processes aimed at addressing the pressing challenge of organic dyes pollutant contamination. Further research and exploration of its adsorption properties can unveil its full potential for future applications as a dye adsorbent.

Sustainable oil palm trunk fibre based activated carbon for the adsorption of methylene blue

Activated carbon (AC) is becoming the limelight due to its widespread application as an adsorbent for wastewater treatment, gases, and catalysis. However, its high consumption and price have drawn more attention to the sustainable use of natural resources as precursor for AC production. This study focuses on synthesising AC from two types of oil palm trunk (OPT) fibres, a significant agricultural waste products produced by Malaysia's thriving palm oil industries. The BET surface area of about 2057.9 m2 g−1 was achieved by chemical activation with phosphoric acid (H3PO4). The efficiency of the synthesised AC was critically analysed based on the adsorption experiments with methylene blue (MB) by varying several parameters (dosage of adsorbent, pH, initial dye concentration, and temperature of the solution) to elucidate the adsorption mechanism(s). A maximum adsorption capacity of 320.4 mg g−1 at 50 °C was achieved, and the Temkin (r2 = 0.98, 0.95, 0.95) and Langmuir (r2 = 0.94, 0.93, 0.95) isotherm models fitted the adsorption process better than the Freundlich (r2 = 0.95, 0.90, 0.86) model. Besides, the pseudo-second-order model (r2 > 0.90) best described the adsorption process, favouring chemisorption over physisorption. Thermodynamics showed MB adsorption on AC was spontaneous except at the highest dye concentration. It was exothermic at lower dye concentrations (50 and 100 mg L−1) and endothermic at higher ones (300, 500, and 700 mg L−1). In a nutshell, this study reveals that OPT fibre is a promising precursor for synthesising highly porous AC for the adsorption of MB dye.

Jute Stick-Derived Cellulose-Based Hydrogel: Synthesis, Characterization, and Methylene Blue Removal from Aqueous Solution.

In this work, microcrystalline cellulose (MCC) was isolated from jute sticks and sodium carboxymethyl cellulose (Na-CMC) was synthesized from the isolated MCC. Na-CMC is an anionic derivative of microcrystalline cellulose. The microcrystalline cellulose-based hydrogel (MCCH) and Na-CMC-based hydrogel (Na-CMCH) were prepared by using epichlorohydrin (ECH) as a crosslinker by a chemical crosslinking method. The isolated MCC, synthesized Na-CMC, and corresponding hydrogels were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electronic microscopy (SEM), and energy dispersive spectroscopy (EDS) for functional groups, crystallinity, surface morphology, and composite elemental composition, respectively. Pseudo-first-order, pseudo-second-order, and Elovich models were used to investigate the adsorption kinetics. The pseudo-second-order one is favorable for both hydrogels. Freundlich, Langmuir, and Temkin adsorption isotherm models were investigated. MCCH follows the Freundlich model (R2 = 0.9967), and Na-CMCH follows the Langmuir isotherm model (R2 = 0.9974). The methylene blue (MB) dye adsorption capacities of ionic (Na-CMCH) and nonionic (MCCH) hydrogels in different contact times (up to 600 min), initial concentrations (10-50 ppm), and temperatures (298-318 K) were investigated and compared. The maximum adsorption capacity of MCCH and Na-CMCH was 23.73 and 196.46 mg/g, respectively, and the removal efficiency of MB was determined to be 26.93% for MCCH and 58.73% for Na-CMCH. The Na-CMCH efficiently removed the MB from aqueous solutions as well as spiked industrial wastewater. The Na-CMCH also remarkably efficiently reduced priority metal ions from an industrial effluent. An effort has been made to utilize inexpensive, readily available, and environmentally friendly waste materials (jute sticks) to synthesize valuable adsorbent materials.