Kinetics and equilibrium studies from the methylene blue adsorption on diatomite treated with sodium hydroxide

Diatomite was treated with sodium hydroxide to remove impurity in order to improve its performance as an adsorbent. The raw diatomite and purified diatomite were characterized by scanning electron microscopy, energy dispersive X-ray analysis and Brunauer–Emmett–Teller adsorption. It was found that the surface area was in order of 15.87 m² g^− 1 for raw diatomite and 31.35 m² g^− 1 for purified diatomite. Scanning electron microscopy images showed the well-developed porous structure of purified diatomite. Purified diatomite improved a more than tenfold increase in adsorption amount from 1.72 mg g^− 1 to 18.15 mg g^− 1 and removal efficiency from 8.60% to 90.75% for methyelen blue initial concentration 100 ppm respectively. The kinetics studies showed that experiment data followed pseudo-second-order model better. The equilibrium data was fitted to Langmuir and Freundlich adsorption isotherms and was found that Langmuir model presented the best fit, showing maximum monolayer adsorption capacity of 27.86 mg g^− 1. The thermodynamic parameters such as the standard enthalpy, standard entropy and standard free energy were evaluated. The obtained results indicated the adsorption of methylene blue onto diatomite treated with sodium hydroxide is endothermic and spontaneous process and confirmed the applicability of this purified inorganic material as an efficient adsorbent for basic dyes.     

Chitosan modified with Reactive Blue 2 dye on adsorption equilibrium of Cu(II) and Ni(II) ions

This study aimed at immobilizing Reactive Blue 2 (RB 2) dye in chitosan microspheres through nucleophilic substitution reaction. The adsorbent chemical modification was confirmed by Raman spectroscopy and thermogravimetric analysis. This adsorption study was carried out with Cu(II) and Ni(II) ions and indicated a pH dependence, while the maximum adsorption occurred around pH 7.0 and 8.5, respectively. The pseudo second-order kinetic model resulted in the best fit with experimental data obtained from Cu(II) (R = 0.997) and Ni(II) (R = 0.995), also providing a rate constant, k₂, of 4.85 × 10⁻⁴ and 3.81 × 10⁻⁴ g (mg min)⁻¹, respectively, thus suggesting that adsorption rate of metal ions by chitosan-RB 2 depends on the concentration of ions on adsorbent surface, as well as on their concentration at equilibrium. The Langmuir and Freundlich isotherm models were employed in the analysis of the experimental data for the adsorption, in the form of linearized equations. Langmuir model resulted in the best fit for both metals and maximum adsorption was 57.0 mg g⁻¹ (0.90 mmol g⁻¹) for Cu(II) and 11.2 mg g⁻¹ (0.19 mmol g⁻¹) for Ni(II). The Cu(II) and Ni(II) ions were desorbed from chitosan-RB 2 with aqueous solutions of EDTA and H₂SO₄, respectively.     

Artificial neural network optimization for removal of hazardous dye Eosin Y from aqueous solution using Co2O3-NP-AC: Isotherm and kinetics study

The present research is focused on the synthesis and characterization of cobalt (III) oxide (Co₂O₃) nanoparticle loaded on activated carbon to prepare an outstanding sorbent for the removal of eosin Y (EY) as hazardous dye from aqueous solution. The sorbent was identified by SEM and XRD analysis. The effect of solution pH, adsorbent dosage (0.005–0.02 g), contact time (0.5–30 min) and initial eosin Y concentration (30–80 mg L⁻¹) on the adsorption process was investigated and modeled by artificial neural network. Following optimization of variables, the experimental equilibrium data was analysis by Langmuir, Freundlich, Tempkin and D–R isothermal models and explored that the data well presented by Langmuir model with a maximum adsorption capacity of 555.56 mg g⁻¹ at 25 °C. Kinetic studies at various adsorbent dosage and initial EY concentrations show that high removal percentage (>90%) was achieved within 15 min of the start of every experiment at most conditions. The adsorption of EY follows the pseudo-second-order rate equation in addition to intraparticle diffusion model. The experimental data were applied to train the multilayer feed forward neural network with three inputs and one output with different algorithms and different numbers of neurons in the hidden layer. The minimum mean squared error (MSE) of 1.49e − 04 and determination coefficient of (R²) 0.9991.     

Removal of Reactive Blue 21 onto magnetic chitosan microparticles functionalized with polyamidoamine dendrimers

Chitosan/poly(amidoamine) (MCS/PAMAM) microparticles were prepared as magnetic adsorbents for removal of Reactive Blue 21 (RB 21) dye from aqueous solution. Characterization of these particles was carried out using scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray diffractometry and vibrating sample magnetometry. The results indicate that the magnetic chitosan microparticles (MCS) were functionalized with PAMAM dendrimers and maintained its intrinsic magnetic properties. The effects of initial pH, adsorbent dose, initial concentration, contact time and temperature on adsorption were investigated. Kinetic studies showed that the dye adsorption process followed a pseudo-second-order kinetic model but that the adsorption rate was also influenced by intraparticle diffusion. Equilibrium adsorption isotherm data indicated a good fit to the Langmuir isotherm. The maximum adsorption capacities obtained from the Langmuir model were 555.56, 588.24, 625.00 and 666.67 mg g⁻¹ at 303, 313, 323 and 333 K, respectively. The thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of the adsorption. Recycling experiments confirmed the relative reusability of the adsorbent.     

Palladium,silver, and zinc oxide nanoparticles loaded on activated carbon as adsorbent for removal of bromophenol red from aqueous solution

The adsorption of bromophenol red (BPR) onto three adsorbents including palladium, silver and zinc oxide nanoparticles loaded on activated carbon (Pd-NP-AC, Ag-NP-AC and ZnO-NP-AC) in a batch system has been studied and the influence of various parameters has been optimized. The influence of time on removal of BPR on all adsorbent was investigated and experimental data were analyzed by four kinetic models including pseudo first and second-order, Elovich and the intraparticle diffusion equations. Following fitting the experimental data to these models, the respective parameters of each model such as rate constants, equilibrium adsorption capacities and correlation coefficients for each model were investigated and based on well known criterion their applicability was judged. It was seen that the adsorption of BPR onto all adsorbents sufficiently described by the pseudo second-order equation in addition to interparticle diffusion model. The adsorption of BPR on all adsorbent was investigated at various concentration of dye and the experimental equilibrium data were analyzed and fitted to the Langmuir, Freundlich, Tempkin, Dubinin, and Radushkevich equations. A single stage in batch process was efficient and suitable for all adsorbents using the Langmuir isotherm with maximum adsorption of 143 mg g^?1 for Pd-NP-AC, 250 mg g^?1 for Ag-NP-AC and 200 mg g^?1 for ZnO-NR-AC. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° for Pd-NP-AC adsorbent were calculated.     

Study of competitive adsorption of malachite green and sunset yellow dyes on cadmium hydroxide nanowires loaded on activated carbon

Cadmium hydroxide nanowires loaded on activated carbon (Cd(OH)₂-NW-AC) was applied for removal of malachite green (MG) and sunset yellow (SY) in single and binary component systems. This novel material was characterized and identified by different techniques such as Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis. Unique properties such as high surface area (>1271 m² g⁻¹) and low pore size (<35 Å) and average particle size lower than 50 Å in addition to high reactive atom and presence of various functional groups make it possible for efficient removal of these two dyes. In the single component system in this study, maximum adsorption capacity of 80.6 for SY and 19.0 mg g⁻¹ for MG at 25 °C was reported. The Langmuir model had very well fit with the experimental data (R² > 0.996). A better agreement between the adsorption equilibrium data and mono-component Langmuir isotherm model was found. The kinetics of adsorption for single and binary mixture solutions at different initial dye concentrations were evaluated by the nonlinear first-order and second-order models. The second-order kinetic model had very well fit with the dynamical adsorption behavior of a single dye for lower and higher initial dye concentrations. SY and MG without spectra overlapping were chosen and analyzed with high accuracy in binary solutions. The effect of multi-solute systems on the adsorption capacity was investigated. The isotherm constants for SY and MG were also calculated in binary component systems at concentrations within moderate ranges, the Langmuir isotherm model satisfactorily predicted multi-component adsorption equilibrium data. The competitive adsorption favored the SY in the A mixture solution (both SY and MG concentration at 10 mg L⁻¹) and B mixture solution (25 mg L⁻¹ of SY and 10 mg L⁻¹ of MG). Also, in both cases, kinetic data was fairly described by two-step diffusion model. An endothermic and spontaneous nature for the adsorption of the dyes studied were shown from thermodynamic parameters in single and binary component systems.     

Ionic liquid based periodic mesoporous organosilica: An efficient support for removal of sunset yellow from aqueous solutions under ultrasonic conditions

The efficiency of an ionic liquid based periodic mesoporous organosilica (PMO-IL) in the removal of sunset yellow from aqueous solutions using ultrasonic assisted adsorption method was investigated. The PMO-IL was first characterized by nitrogen sorption and TEM techniques. The optimized conditions (0.013 g of adsorbent, 32 mg L⁻¹ of sunset yellow at 2 min of sonication time and pH 7) were obtained by central composite design (CCD). Fitting the equilibrium data show the suitability of the Langmuir model with second-order equation to control the kinetic of the adsorption process and good reusability (5 cycles) of PMO-IL for adsorption of dye.     

Removal of Acid Green 68:1 from aqueous solutions by calcined and uncalcined layered double hydroxides

Magnesium aluminum layered double hydroxide (LDH) was synthesized by the co-precipitation method followed by calcination. The resulting materials were characterized by X-ray diffraction (PXRD) and attenuated total reflectance with Fourier transform infrared spectroscopy (FTIR/ATR) and simultaneous thermogravimetric analysis/differential scanning calorimetry coupled to mass spectrometry (TGA–DSC–MS). Calcined and non-calcined LDHs were used as adsorbents to remove azo dye Acid Green 68:1 in an aqueous solution. Adsorption experiment results indicated that calcined LDH possesses greater adsorption capacity (154.8 mg g^− 1) than non-calcined LDH (99.1 mg g^− 1). Isotherms showed that adsorption of the dye was more consistent with the Langmuir model. Kinetic experiments of calcined LDH adsorption showed that for low concentration (50, 100 and 200 mg L^− 1), the system reached the adsorption equilibrium in 1, 2, and 4 h, and for higher concentration after 10 h. The best kinetic model was the pseudo-second order. Adsorption studies also showed that the capacity for adsorption of the dye by calcinated LDH does not significantly diminish with pH level variation.     

Controllable synthesis of mesoporous alumina with large surface area for high and fast fluoride removal

Gamma phase of mesoporous alumina (MA) with large surface area was successfully synthesized by a facile hydrothermal method followed by thermal treatment for fluoride removal. The as-synthesized MA nanoparticles with average size of 20 nm–150 nm have ordered wormhole-like mesoporous structure. The pore size is 5 nm with a narrow distribution, and the specific surface area reaches 357 m² g⁻¹ while the bulk density is 0.45 cm³ g⁻¹. Glucose as a small-molecule template plays an important role on the morphology, surface area and pore diameter of the MA. As an ionic adsorbent for fluoride removal, the maximum adsorption capacity of MA is 8.25 mg g⁻¹, and the remove efficiency reaches 90% in several minutes at pH of 3. The Langmuir equilibrium model is found to be suitable for describing the fluoride sorption on MA and the adsorption behavior follows the pseudo-second-order equation well with a correlation coefficient larger than 0.99. The larger surface area and relatively narrow pore size of MA are believed to be responsible for improving the adsorption efficiency for fluoride in aqueous solution.     

Removal of malachite green from aqueous solution by zinc oxide nanoparticle loaded on activated carbon: Kinetics and isotherm study

In this research, a novel adsorbent, zinc oxide nanoparticle loaded on activated carbon (ZnO-NP-AC) was synthesized by a simple, low cost and efficient procedure. Subsequently, this novel material was characterizated and identified by different techniques such as Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis. Unique properties such as high surface area (>603 m²/g) and low pore size (<61 Å) and average particle size lower than 100 Å in addition to high reactive atom and presence of various functional groups make it possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal of MG by ZnO-NP-AC was attained following searching effect of variables such as adsorbent dosage, initial dye concentration and pH. Optimum values were set as pH of 7.0, 0.015 g of ZnO-NP-AC at removal time of 15 min. Kinetic studies at various adsorbent dosage and initial MG concentration show that maximum MG removal was achieved within 15 min of the start of every experiment at most conditions. The adsorption of MG follows the pseudo-second-order rate equation in addition to interparticle diffusion model (with removal more than 95%) at all conditions. Equilibrium data fitted well with the Langmuir model at all amount of adsorbent, while maximum adsorption capacity was 322.58 mg g⁻¹ for 0.005 g of ZnO-NP-AC.     

Synthesis of electrically conducting composite adsorbents for wastewater treatment using adsorption & electrochemical regeneration

Electrically conducting adsorbent materials called Nyex™ 1000 & 2000 have already been reported with comparatively low adsorption capacity for various organic, biologically non-degradable and toxic compounds. Two composite adsorbents called CA₁ & CA₂ were synthesized using synthetic graphite-carbon black and expanded graphite-carbon black respectively. The aim of developing the new adsorbents was to increase the adsorption capacity along with good electrical properties. The developed adsorbents were characterized using N₂ adsorption for specific surface area, Boehm surface titration for surface chemistry, bed electrical conductivity, laser size analyzer for average particle size, and scanning electron microscope (SEM) for particle morphology and shape. Then both the composite adsorbents were tested for the adsorption of acid violet 17 followed by an electrochemical regeneration. The adsorption study revealed that both the adsorbents had almost similar kinetic behavior with a significant increase in adsorption capacity for acid violet 17 (300 & 26 mg g⁻¹ respectively) when compared with the adsorption capacity of previously developed electrically conducting materials called Nyex™ 1000 & 2000 (3.5 and 9 mg g⁻¹ respectively). The composite adsorbent CA₂ was successfully electrochemically regenerated by passing an electric charge of 138 C g⁻¹ at a current density of 14 mA cm⁻² for a treatment time of 60 min, whereas, the composite adsorbent CA₁ could not be regenerated successfully. The regeneration efficiencies of CA₂ were obtained at around 120% during five adsorption–regeneration cycles. The amount of actual charge passed of 138 C g⁻¹ for achieving 100% regeneration efficiency was found to be similar with stoichiometrically calculated amount of charge. The amount of electrical energy required to oxidize each mg of adsorbed acid violet onto CA₂ (24 J mg⁻¹) was found to be significantly lower to that of Nyex™ 1000 & 2000 adsorbents (52 J mg⁻¹ & 32 J mg⁻¹ respectively).     

Nano-TiO2 modified with 2-mercaptobenzimidazole as an efficient adsorbent for removal of Ag(I) from aqueous solutions

Nano-TiO₂ was modified with 2-mercaptobenzimidazole via surfactant activation and used as an adsorbent for the removal of Ag(I) under optimum conditions. The adsorbent was characterized using powder X-ray diffraction and FT-IR spectroscopy. The equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models. Langmuir isotherm describes the adsorption data better than Freundlich isotherm and Temkin. Kinetic studies showed that the pseudo second order kinetic model fits the adsorption kinetic processes well. Maximum adsorption capacity for Ag(I) was 128.2 mg g⁻¹ of nano-TiO₂. The method was successfully applied to the removal of silver from radiology film processing wastewater samples.     

Sorption of heavy metal ions from aqueous solution by a novel cast PVA/TiO2 nanohybrid adsorbent functionalized with amine groups

Sorption of Cd(II), Ni(II) and U(VI) ions onto a novel cast PVA/TiO₂/APTES nanohybrid adsorbent with variations in adsorbent dose, pH, contact time, initial metal concentration and temperature has been investigated. The adsorbent were characterized by SEM and FTIR analysis. BET surface area, pore diameter and pore volume of adsorbent were 35.98 m² g⁻¹, 3.08 nm and 0.059 cm³ g⁻¹, respectively. The kinetic and equilibrium data were accurately described by the double-exponential and Freundlich models for all metals. The maximum sorption capacities were 49.0, 13.1 and 36.1 mg g⁻¹ for Cd(II), Ni(II) and U(VI) ions with pH of 5.5, 5 and 4.5, respectively. Thermodynamic studies showed that the sorption process was favored at higher temperature. The adsorbent can be easily regenerated after 5 cycles of sorption–desorption.     

Effect of heparin coating on epichlorohydrin cross-linked chitosan microspheres on the adsorption of copper (II) ions

Epichlorohydrin cross-linked chitosan microspheres (CS) and chitosan–heparin polyelectrolyte complex microspheres (CSH) were used in the adsorption of copper (II) ions in aqueous solution. The chitosan microspheres were prepared by the phase inversion method. The use of a cross-linking agent improved the resistance to acidic medium. Polyelectrolyte complex microspheres were prepared by impregnating heparin in cross-linked chitosan microspheres. The microspheres were characterized by IR, TGA and DSC. A study on the effect of the pH on the adsorption of copper (II) ions showed that the optimum pH for both CS and CSH microspheres was 6.0. From a kinetic evaluation, it could be established that the adsorption equilibrium was achieved after 8 h for CS and 25 h for CSH microspheres. The adsorption isotherms were interpreted using Langmuir and Freundlich mathematical models. The results revealed that experimental data of CS was best adjusted by Langmuir model, with maximum capacity of surface saturation equal to 39.31 mg g⁻¹. On the other hand, Langmuir and Freundlich models provided a good fit for adsorption by CSH and the adsorption capacity was 81.04 mg g⁻¹. The interactions between copper (II) ions and both CS and CSH were confirmed by electron paramagnetic resonance spectroscopy, which revealed the formation of a square-planar complex with tetrahedral distortion on the surface of the adsorbents.     

Principal component analysis-artificial neural network and genetic algorithm optimization for removal of reactive orange 12 by copper sulfide nanoparticles-activated carbon

In this study a green approach described for the synthesis of copper sulfide nanoparticles loaded on activated carbon (CuS-NP-AC) and usability of it for the removal of reactive orange 12 (RO-12). This material was characterized using instruments such as scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of variables were optimized using Principal component analysis-artificial neural network (PCA-ANN). Fitting the experimental equilibrium data shows the suitability of the Langmuir isotherm. The small amount of proposed adsorbent (0.017 g) is applicable for successful removal of RO-12 (RE > 95%) in short time (31.09 min) with high adsorption capacity (96.9 mg g⁻¹)     

Removal of perchlorate from aqueous solution using protonated cross-linked chitosan

Protonated cross-linked chitosan was used to remove perchlorate from aqueous solution. Adsorption isotherms, the effects of pH and co-existing anions on the adsorption process, proper actual contact time in the adsorption column and the regeneration ability of the adsorbent were investigated. The equilibrium data fitted well with Langmuir and Freundlich isotherm models, and the maximum monolayer adsorption capacity was 45.455 mg g^?1. To balance the protonated degree of the amino groups and the effect of the ion competing on adsorption capacity, the optimal pH value was determined to be about 4.0. Column adsorption results indicated that the proper actual contact time was 8.1 min and the effluent perchlorate could be steadily kept below 24.5 μg L^?1 up to about 95 bed volumes with the influent perchlorate of 10 mg L^?1. The presence of other anions weakened the perchlorate adsorption, especially the high valence anion such as sulfate. The adsorbents could be well regenerated by sodium hydroxide solution with pH 12 and reused at least for 15 cycles. Electrostatic attraction as well as physical force was the main driving force for perchlorate adsorption.     

Solid phase extraction and removal of brilliant green dye on zinc oxide nanoparticles loaded on activated carbon: New kinetic model and thermodynamic evaluation

The brilliant green (BG) solid phase extraction of carried out following accumulation on including zinc oxide nanoparticles loaded on activated carbon (ZNO-NP-AC) non-toxic and green as material. The influence of variables such as pH, initial BG concentration, contact time, amount of adsorbent, eluent and temperature on BG removal and recoveries were studied and optimized. The high correlation coefficient and possibility of accurate prediction and explanation of experimental data by novel kinetic model show its applicability and superiority for representation of experimental data. The results of present model compared with traditional kinetic models (pseudo-first and second order and intraparticle diffusion model). Additionally, fitting the experimental equilibrium data to numerous conventional isotherm models show that the Langmuir model with high correlation coefficient and low error analysis is more usable to explain the experimental data. The calculated change in entropy and enthalpy of BG adsorption on proposed adsorbent was 136.59 J mol⁻¹ K⁻¹ for 15.0 mg L⁻¹ and 65.2 J mol⁻¹ K⁻¹ 35.2 kJ/mol and 16.1 kJ/mol for 15 mg L⁻¹. The quantitative elution of retained BG by 2.0 mL of EtOH make permit accurate and repeatable monitoring off BG over wide linear range (0.2–500 ng mL⁻¹) with limits of detection (LODs) of 0.08 ng mL⁻¹. The preconcentration factors were 75 and loading half time (t_1/2) values were less than 5 min.     

Chitin as biosorbent for phenol removal from aqueous solution: Equilibrium,kinetic and thermodynamic studies

Phenol removal from aqueous solution was studied employing chitin as low cost biosorbent. Initial biosorption tests carried out in the pH range 2–10 pointed out an optimum pH of 2. Temperature and initial phenol concentration were then varied in the ranges 15 ≤ T ≤ 50 °C and 10.4 ≤ C₀ ≤ 90.8 mg L⁻¹, respectively. The good applicability of Langmuir, Freundlich and Temkin models (R² = 0.990–0.993) to describe equilibrium isotherms suggested an intermediate mono-/multilayer biosorption mechanism along with a semi-homogeneous architecture of biosorbent surface. Biosorption capacity progressively increased from 3.56 to 12.7 mg g⁻¹ when starting phenol concentration was raised from 10.4 to 90.8 mg L⁻¹, and the related sorption kinetics was investigated by pseudo first-order, pseudo second-order and intraparticle diffusion models. The pseudo second-order model, which showed the best fit of experimental data (R² = 0.999), allowed estimating a second-order rate constant of 0.151 g mg⁻¹ h⁻¹ and a theoretical sorption capacity of 7.63 mg g⁻¹. Phenol biosorption capacity increased with temperature up to a maximum value, beyond which it decreased, suggesting the occurrence of a thermoinactivation equilibrium. Finally, to identify the main functional groups involved in phenol biosorption, both raw and phenol-bound materials were explored by FT-IR spectroscopy.     

Cathode materials based on carbon nanotubes for high-energy-density lithium–sulfur batteries

The rational integration of conductive nanocarbon scaffolds and insulative sulfur is an efficient method to build composite cathodes for high-energy-density lithium–sulfur batteries. The full demonstration of the high-energy-density electrodes is a key issue towards full utilization of sulfur in a lithium–sulfur cell. Herein, carbon nanotubes (CNTs) that possess robust mechanical properties, excellent electrical conductivities, and hierarchical porous structures were employed to fabricate carbon/sulfur composite cathode. A family of electrodes with areal sulfur loading densities ranging from 0.32 to 4.77 mg cm⁻² were fabricated to reveal the relationship between sulfur loading density and their electrochemical behavior. At a low sulfur loading amount of 0.32 mg cm⁻², a high sulfur utilization of 77% can be achieved for the initial discharge capacity of 1288 mAh g_S⁻¹, while the specific capacity based on the whole electrode was quite low as 84 mAh g_{C/S+binder+Al}⁻¹ at 0.2 C. Moderate increase in the areal sulfur loading to 2.02 mg cm⁻² greatly improved the initial discharge capacity based on the whole electrode (280 mAh g_{C/S+binder+Al}⁻¹) without the sacrifice of sulfur utilization. When sulfur loading amount further increased to 3.77 mg cm⁻², a high initial areal discharge capacity of 3.21 mAh cm⁻² (864 mAh g_S⁻¹) was achieved on the composite cathode.     

Adsorption studies of methylene blue onto ZnCl2-activated carbon produced from buriti shells (Mauritia flexuosa L.)

The present study reports the preparation of an activated carbon produced from buriti shells (AC_b) using ZnCl₂ as activating agent and its ability to remove methylene blue dye (MB) from aqueous solutions. The obtained AC_b was characterized by N₂ adsorption–desorption isotherms, SEM and FT-IR. The results show that AC_b presents microporous features with BET surface area (S_BET) of 843 m² g⁻¹ and functional groups common in carbonaceous materials. Adsorption studies were carried out and experimental data were fitted to three isotherm models (Langmuir, Freundlich, and Redlich–Peterson) and four kinetic models (pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion). The isotherm model which best fitted to experimental data was Redlich–Peterson. However, the g parameter of this model indicated that the adsorption of MB onto AC_b occurs according to the mechanism proposed by Langmuir, which showed maximum monolayer adsorption capacity of 274.62 mg g⁻¹. Kinetic studies demonstrated that the Elovich model is suitable to describe the experimental data. Moreover, it was found that the intraparticle diffusion is the limiting step of adsorption process.