Methylene Blue Adsorption Studies Research Articles

Nigella sativa seed based nanocomposite-MnO2/BC: An antibacterial material for photocatalytic degradation, and adsorptive removal of Methylene blue from water

Antimicrobial Nigella sativa seed-based nanocomposite, MnO2/BC, was synthesized and utilized for the water purification through adsorption, and the photocatalytic degradation. MnO2/BC was prepared by co-precipitation method, and characterized using FT-IR, XRD, SEM, TEM, TGA, and DSC techniques. The composite was investigated for inhibition of bacterial cells growth. FT-IR spectrum indicated the presence of oxygenous groups on the surface; TGA and DSC showed thermal degradation; and XRD, SEM, and TEM investigations indicated amorphous, and porous nature of MnO2/BC having particle size of 190–220 nm. The nanocomposite inhibited the growth of both Gram-positive and Gram-negative bacteria cells in water. The adsorption of Methylene blue from water was investigated in batch method in terms of amount of MnO2/BC, dye concentration, pH, time, and temperature. 1.0 g L−1 of MnO2/BC removed more than 98% of Methylene blue from aqueous solution having concentration of 10 mg L−1 and pH 7.0 at 27 °C. The maximum Langmuir adsorption capacity of MnO2/BC was 185.185 mg g−1 at 45 °C. The adsorption was an endothermic process which obeyed Freundlich isotherm, and pseudo-second order kinetics. Therefore, the Methylene blue binding onto MnO2/BC surface was site-specific partially through the weak hydrogen bonding, and electrostatic interactions. The photocatalytic activity of MnO2/BC has been investigated by degrading the Methylene blue molecules/ions in water under the sunlight and 85% of degradation was achieved during 120 min irradiation. The dye was desorbed at lower pH and regenerated MnO2/BC was used for second cycle of Methylene blue adsorption. The results obtained for this study are much better than the previous Methylene blue adsorption studies with acid washed Black cumin seeds and MnFe2O4/BC for which the capacities were 73.529 mg g−1 and 10.070 mg g−1 at 27 °C, respectively (J. Mol. liq. 2018a, 264, 275–284; J. Clean. Prod. 2018a, 200, 996–1008).

Kinetics, Isotherm, and Thermodynamic Studies of Methylene Blue Adsorption on Polyaniline and Polypyrrole Macro-Nanoparticles Synthesized by C-Dot-Initiated Polymerization.

This work unraveled kinetics, isotherm, and thermodynamic properties of methylene blue (MB) adsorbed on polyaniline (PANI) and polypyrrole (PPY). The two polymers, PANI and PPY, synthesized by a facile C-dot (CD)-initiated polymerization method have been proven as the effective adsorbent materials to remove MB from wastewater. This dye model is also generally employed as a redox indicator in analytical chemistry and exhibits blue in an oxidizing environment, but it is colorless when exposed to a reducing agent. The effects of temperature, adsorbent amount contact time, and dye concentration were consistently examined. The adsorption capacity of the polymers at 28 °C could reach 19.2 mg/g. The adsorption equilibrium of the dye was attained after 90 and 120 min of contact time with PANI and PPY, respectively. The equilibrium details were well described by Freundlich and Langmuir isotherms. Results showed that PANI and PPY prepared using CD-initiated polymerization are better adsorbents compared to the commercial PANI powder for the removal of MB from water.

Equilibrium isotherms, kinetics, and thermodynamics studies of methylene blue adsorption on pomegranate (Punica granatum) peels as a natural low-cost biosorbent

Equilibrium isotherms, kinetics, and thermodynamics studies of methylene blue adsorption on pomegranate (Punica granatum) peels as a natural low-cost biosorbent

Isotherm studies of methylene blue adsorption onto waste tyre pyrolysis powder-based activated carbons

This study was aimed to investigate the adsorptive ability of activated carbons derived from waste tyre pyrolysis powder by CO2 activation and ZnCl2 activation. The derived activated carbons and char were characterized for yield and specific surface area. Methylene Blue dye was used as a model pollutant to probe the performance of activated carbons. Result shows that the CO2-activated waste tyre pyrolysis powder exhibits a higher surface area of 97.0 m2/g, hence a greater methylene blue removal capacity of 47.2 mg/g. The methylene blue adsorption data by activated carbons and char obeyed the Langmuir isotherm with R2 of more than 0.99, describing the monolayer adsorption onto homogeneous surface. Physical activation of waste tyre pyrolysis powder using CO2 yields activated carbon with a promising performance for dyes removal from water.

Low-Cost and High-Capacity Dye Remover: a Study of Methylene Blue Adsorption by a Thermoplastic-Elastomer Blend System

A thermoplastic elastomer blend of sulfonated polystyrene-block-poly-(ethylene-ran-butylene)-block-polystyrene (SEBS) copolymer with polypropylene (PP) has been studied for its promising application as an adsorbent. Batch adsorption experiments were performed for the removal of cationic methylene blue from aqueous solution. A detailed characterization on the adsorbent blend was carried out by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry (TGA) in order to determine the microstructural identity and thermal stability. Thermodynamic parameters and kinetic model of the adsorption process were evaluated. High adsorption values were obtained depending on the initial dye concentration and temperature from 303 to 400 mg/g. Gibbs free energy values of the adsorption were found to be 8.6, 5.5, and 5.3 kJ/mol at temperatures 275, 298, and 313 K, respectively, suggesting that the process is not spontaneous. The enthalpy of the adsorption was − 34.2 kJ/mol which indicates that the process is slightly out of physisorption range but at the beginning of chemisorption rage and exothermic in nature. Adsorption process caused a small increase in the disorder with a value of 93.9 J/K mol. Dye adsorption process were found to comply with pseudo-second-order kinetics. Adsorption data were well fitted by Langmuir isotherm model. The study showed that thermoplastic elastomer adsorbent film introduced here has a potential to be an economical alternative to available adsorbents for cationic dye removal of waste waters.

Kinetics, isotherm, and thermodynamic studies of methylene blue adsorption from water by Mytella falcata waste.

This work evaluates the application of Mytella falcata shells, discarded in large quantities in the state of Alagoas, Brazil, as adsorbent for methylene blue dye (MB). It was investigated how the amount of adsorbent (M), the average particle diameter (G), and the agitation speed (A) affected the adsorption. Kinetic and equilibrium studies were conducted, and the pseudo-second-order equation adequately represented the kinetic data and isotherms following Liu's model (q max=8.81mgg-1 at 60°C). The adsorption was spontaneous, favorable, and endothermic. Mytella falcata shell is a suitable adsorbent for MB and could potentially contribute to its removal from the environment.

Kinetics and equilibrium studies of methylene blue adsorption on 2D nanolamellar Fe3O4

ABSTRACTNanolamellar Fe3O4 as magnetic adsorbents was prepared using sodium dodecyl sulfonate as a template. Thermogravimetric measurements characterisation showed that the as-synthesised product contained about 6 wt% sodium dodecyl sulfonate. The adsorption performance of nanolamellar Fe3O4 for the removal of organic dye from aqueous solution was evaluated using methylene blue as a model dye. The product exhibited an excellent ability to adsorb methylene blue from aqueous solutions with a maximum methylene blue removal rate of 96.8%. The adsorption kinetics can be described by a pseudo-second-order equation, and the adsorption isotherm agreed well with Langmuir adsorption equation. Furthermore, the dye saturated nanolamellar Fe3O4 could be regenerated using acidic ethanol solution, and the nanolamellar Fe3O4 showed excellent reusability. The results indicate the potential use of the adsorbent for the removal of methylene blue from aqueous solution.

Kinetic Studies of Methylene Blue Adsorption on to Activated Carbon Prepared from Plantain Pod (Musa paradisiac)

Kinetic Studies of Methylene Blue Adsorption on to Activated Carbon Prepared from Plantain Pod (Musa paradisiac)

Surface characterization and methylene blue adsorption studies on a mesoporous adsorbent from chemically modified Areca triandra palm shell

Activated carbon was prepared from Areca triandra palm shell (ATPS) by chemical activation with sulphuric acid, and its application for the adsorption of methylene blue dye from aqueous solution was investigated. FTIR spectral analysis and Boehm titrations were used to examine the oxygenated surface functional groups tailored to adsorb cationic toxins from solutions, point of zero charge estimated the surface charge for electronic affinity induced by chemical treatment. BET and SEM analyses revealed mesoporous adsorbent with homogenous pores and the BET surface area is 27.3 m2/g. The influence of process parameters, namely contact time, initial concentration, adsorbent dosage and pH was evaluated by batch adsorption studies. The equilibrium adsorption data were fitted with three isotherm models, among them Langmuir isotherm model best fitted and the maximum adsorption capacity of methylene blue was found to be 312.5 mg/g. The kinetic adsorption data best fitted with pseudo-second-order kinetics out of three kinetic models tested. The thermodynamic parameters, Gibb’s free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) ascertain that the adsorption is a spontaneous endothermic process with high affinity between surface and dye. The results of the present study suggest that the adsorbent prepared from ATPS is a potential adsorbent for the treatment of effluent containing cationic dyes.

Experimental and modeling studies of methylene blue adsorption onto particles of peanut shell

ABSTRACTIn this study, adsorption of methylene blue from aqueous solution onto peanut shell has been investigated. Experimental data obtained from dye adsorption have been studied by five two-parameter (Langmuir, Freundlich, Dubinin–Radushkevich, Temkin, and Frumkin) and five three-parameter (Redlich–Peterson, Sips, Toth, Radke–Prausnitz, and Koble–Corrigan) isotherm models. Eight nonlinear error functions (sum squares errors, hybrid fractional error function, Marquardt’s percent standard deviation, average relative error, sum of absolute error, the coefficient of determination, nonlinear chi-square test, and standard deviation of relative errors) were examined for isotherm equations. In order to explain the adsorption kinetics fit of pseudo-first-order, pseudo-second-order, Elovich, and intraparticle kinetic models were used. The best fitting isotherm model was the Radke–Prausnitz and kinetics model was pseudo-second-order. Adsorption experiment showed that the maximum capacity of agricultural waste for methylene blue was 67.57 L · g−1 at 25°C.

Methylene Blue Adsorption on the Basal Surfaces of Kaolinite: Structure and Thermodynamics from Quantum and Classical Molecular Simulation

AbstractOrganic dyes such as methylene blue (MB) are often used in the characterization of clays and related minerals, but details of the adsorption mechanisms of such dyes are only partially understood from spectroscopic data, which indicate the presence of monomers, dimers, and higher aggregates for varying mineral surfaces. A combination of quantum (density functional theory) and classical molecular simulation methods was used to provide molecular detail of such adsorption processes, specifically the adsorption of MB onto kaolinite basal surfaces. Slab models with vacuum-terminated surfaces were used to obtain detailed structural properties and binding energies at both levels of theory, while classical molecular dynamics simulations of aqueous pores were used to characterize MB adsorption at infinite dilution and at higher concentration in which MB dimers and one-dimensional chains formed. Results for the neutral MB molecules are compared with those for the corresponding cation. Simulations of the aqueous pore indicate preferred adsorption on the hydrophobic siloxane surface, while charge-balancing chloride ions adsorb at the aluminol surface. At infinite dilution and in the gas-phase models, MB adsorbs with its primary molecular plane parallel to the siloxane surface to enhance hydrophobic interactions. Sandwiched dimers and chains are oriented perpendicular to the surface to facilitate the strong hydrophobic intermolecular interactions. Compared with quantum results, the hybrid force field predicts a weaker MB adsorption energy but a stronger dimerization energy. The structure and energetics of adsorbed MB at infinite dilution are consistent with the gas-phase binding results, which indicate that monomer adsorption is driven by strong interfacial forces rather than by the hydration properties of the dye. These results inform spectroscopic studies of MB adsorption on mineral surfaces while also revealing critical areas for development of improved hybrid force fields.

Kinetic and equilibrium study of methylene blue adsorption using H2SO4− activated rice husk ash

The objective of this study is to evaluate the performance of H2SO4− activated rice husk ash (ARHA) (burned at different temperatures (300–550°C) as compared to granular activated carbon (GAC) in the removal of methylene blue (MB) from aqueous solution. Batch studies were performed to evaluate the influences of various experimental parameters like pH (4, 7, 9, and 11), initial concentration (5, 10, 15, 20, 25, and 50 mg/L), and contact time (0, 1, 5, 15, 30, 45, 60, 90, and 120 min). BET surface areas for ARHA300 (burned at 300°C) and ARHA550 (burned at 550°C) were determined as 143 and 68 m2/g, respectively. It was observed that the dye uptake by GAC and ARHA300 were not changed significantly when the pH of dye solution was increased from 4 to 11. Uptakes of dye were rapid and the adsorption increased with increasing contact time in all experiments. According to the R2 values for the adsorption of MB on ARHA300, ARHA500, and GAC, Langmuir model yields fit better than the Freundlich model. The maximum adsorption capacity, qmax of ARHA300 (44.25 mg/g), had the highest value. The pseudo-second-order kinetic model yields the best fit for adsorption on ARHA300 and ARHA550 and the correlation coefficients R2 of the model for the linear plots are very close to 1 at various concentrations.

Kinetic modeling of methylene blue adsorption onto acid-activated spent tea: A comparison between linear and non-linear regression analysis

The kinetic study of methylene blue (MB) adsorption using acid-activated spent tea (AAST) as an adsorbent from aqueous solution with the aim of comparing linear and non-linear regression analysis methods was performed at varying initial MB concentrations (10-100 mg/l). Hence, spent tea leaves, which were activated using concentrated sulfuric acid, were prepared. The physicochemical characteristics of the prepared adsorbent were also measured. In addition, a scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) instruments were employed to determine the size, morphology, and functional groups of AAST. Furthermore, the influence of different particle sizes of adsorbent on the adsorptive removal efficiency of MB was evaluated. The obtained data on MB adsorption were fitted using 4 kinetic models, namely pseudo first-order, pseudo second-order, Elovich, and intraparticle diffusion (I-D). The results of kinetic investigations showed that pseudo second-order kinetic model compared to the other applied models, with significant coefficient of determination (r 2 > 0.98), could best fit the experimental data of MB adsorption. In addition, among all linear forms of the pseudo second-order model, form 1 could better fit the MB adsorption data. Additionally, by comparing the performance of both linear and non-linear forms of the pseudo second-order kinetic model, it can be postulated that non-linear regression analysis could be more appropriate than the linear approach for kinetic study of MB adsorption onto the AAST adsorbent. Ultimately, based on the results of particle size experiments, the smaller the size of the adsorbent particles, the higher the adsorption efficiency of MB will be.

Kinetics Study of Methylene Blue Adsorption Onto Activated Carbon by Means of Spectrophotometry

Goal of this work is to explore adsorption phenomenon of methylene blue on activated carbon. The adsorption process was monitored at 30 0C and 50 0C. We used spectrophotometric method for concentration estimation and on the basis of obtained results we proposed kinetics mechanism and equilibrium isotherms. Adsorption has been found to be an efficient and economically cheap process to remove pollutants such as colors, dyes and metal impurities. Adsorption processes using activated carbons are widely used to remove pollutants from wastewater. By fitting experimental results, pseudo-second order and Elovichev model gave very satisfactory results with the correlation coefficient R = 0.99994 and R = 0.99973, successively. Equilibrium isotherms of the methylene blue on the activated carbon were determined and correlated with common isotherm equation Freundlich, Langmuir and Temkin model. Rate of adsorption increased with increase in experimental temperature, which goes in favor of endothermic process. Adsorption of methylene blue onto activation carbon is happening probably through chemisorption path.

Study of Methylene Blue adsorption on keratin nanofibrous membranes

In this work, keratin nanofibrous membranes (mean diameter of about 220nm) were prepared by electrospinning and tested as adsorbents for Methylene Blue through batch adsorption tests. The adsorption capacity of the membranes was evaluated as a function of initial dye concentration, pH, adsorbent dosage, time and temperature. The adsorption capacity increased with increasing the initial dye concentration and pH, while it decreased with increasing the adsorbent dosage and temperature, indicating an exothermic process. The adsorption results indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich and Temkin isotherm models.A mean free energy evaluated through the Dubinin–Radushkevich model of about 16kJmol−1, indicated a chemisorption process which occurred by ion exchange. The kinetic data were found to fit the pseudo-second-order model better than the pseudo-first-order model. The obtained results suggest that keratin nanofibrous membranes could be promising candidates as dye adsorption filters.

Natural Portuguese clayey materials and derived TiO2-containing composites used for decolouring methylene blue (MB) and orange II (OII) solutions

The use of some Portuguese clay materials as alternative low-cost adsorbents, as well as substrates to immobilize titania for decolouring methylene blue (MB) and orange II (OII) dye solutions, was studied. For MB adsorption studies, the experimental data were mathematically fitted using Langmuir and Freundlich adsorption models. The clayey materials showed distinct adsorption behaviour. The dye removal was high with the use of the bentonite-rich sample collected on the Benevila region (AV), the other illitic–kaolinitic (OV) and kaolinitic (BA) presented lower efficiency. The studied clays were not capable to adsorb OII dye molecules, due to their anionic character. The removal of OII was improved by using photocatalysis, testing new clay/titania composites prepared by mixing distinct proportions of each component. Decolouring of OII solutions reached acceptable levels (between 94–80%), but the materials are less efficient than pure commercial TiO2 powder. Concerning MB solutions, the combined effect of adsorption and photocatalysis resulted in very satisfactory performances, even for mixtures containing relatively low content of TiO2 catalyst. By testing titania gel impregnated clays, high OII decolouration efficiency (up to 99%) is obtained in short time (2h). However, the decolouration of MB solutions by these materials was much slower (20h) although the final colour attenuation reached 96.5%.

Kinetics and isotherm studies of methylene blue adsorption onto polyaniline nanotubes base/silica composite

A cationic dye, such as methylene blue (MB), was adsorbed from water by using polyaniline nanotubes (PANI NTs) base/silica composite as adsorbent. Experiments were conducted by using the UV–visible spectroscopy and by varying parameters namely: initial concentration of MB and contact time. The percentage of color removal decreased with increase of initial dye concentration. Equilibrium data were fit to Langmuir isotherm. The Langmuir isotherm fits best the MB adsorption data on PANI NTs base/silica composite.The kinetic models: pseudo first order, pseudo-second order and the intraparticle diffusion models were applied to the experimental data. It was observed that pseudo-second order kinetic model described the adsorption process better than any other kinetic models. Results obtained indicate that PANI NTs base/silica composite could be employed as an efficient adsorbent much more than the conventional PANI base/silica composite powder for dye uptake.

Thermodynamic studies of methylene blue adsorption onto Fe-doped sulfated titania

Adsorption equilibrium of methylene blue onto Fe-doped sulfated titania (FST) samples was studied at different temperatures (298, 303, and 308 K). Based on the wavelength scanning from 580 to 760 nm, the wavelength of maximum absorbance of methylene blue was determined to be 666 nm and the corresponding calibration curve can be described by the equation of A = 0.0068 + 0.1514C. The adsorption of methylene blue onto FST samples was conformed to the Langmuir isotherms. The absorption capacity of each FST sample for methylene blue increases with increasing temperature. The increase in the adsorption parameters (q m, b, and K 0) and the positive ΔH θ reveal the endothermic feature of this adsorption process. The negative ΔG θ shows the adsorption of methylene blue onto FST samples can be carried out spontaneously at the examined temperatures. Furthermore, with the calcination temperature increases, the variation in crystallization degree, the surface and the sulfur species will obviously influence the adsorption properties of FST samples and the thermodynamic parameters of this adsorption process.

The Kinetic Study of Methylene Blue Adsorption over MgO from PVA Template Preparation

The Kinetic Study of Methylene Blue Adsorption over MgO from PVA Template Preparation

Kinetics Studies of Methylene Blue Adsorption onto Spherical Chitosan Resin

Investigated the sorption kinetics of methylene blue on spherical chitosan resin. Studied the influences of ionic strength, pH， initial concentration on the adsorption process. The adsorption of methylene blue increases with the decreasing ionic strength and the increasing pH and the initial concentration of the system. Furthermore, the adsorption process correspondes with Lagergren pseudo-second kinetic equation and the finess (R2) of the model was above 0.99.