MB Adsorption Capacity Research Articles

Simultaneous removal of cationic methylene blue and anionic reactive red 198 dyes using magnetic activated carbon nanoparticles: equilibrium, and kinetics analysis.

For the simultaneous adsorption of cationic dye (methylene blue, MB) and anionic dye (reactive red 198, RR198) from aqueous solution, magnetic activated carbon (MAC) nanocomposite as a promising adsorbent was prepared and used. The concentration of MB at different time intervals was determined using a UV-Vis spectrophotometer while the concentration of RR198 was determined using a high performance liquid chromatography (HPLC) system. The effect of solution pH, contact time, adsorbent amount, and dye concentration were investigated. Also, both kinetic and isotherm experiments were studied. The optimum pH was 10 and 5.5 for adsorption of MB and RR198, respectively, and the equilibrium status was achieved after 120 min. The adsorption kinetics was controlled by the pseudo-second order kinetic model more than pseudo-first order. The best-fitted isotherms were Freundlich and Langmuir models for MB and RR198, respectively. The higher values of Freundlich adsorption capacity (Kf) for MB in comparison with RR198 refer to MAC affinity to remove cationic dyes more than anionic dyes. Apparently, there was no substantial change in the adsorption efficiency among the 10 adsorption-desorption cycles. Overall, MAC can be considered as an effective and efficient viable adsorbent for cationic and anionic dyes removal from industrial wastewaters.

Rapid and tunable selective adsorption of dyes using thermally oxidized nanodiamond

In the present study, capability of nanodiamond (ND) for the adsorption of anionic (methyl orange, MO) and cationic (methylene blue, MB) dyes from aqueous solution was investigated. Employing fourier transform infrared (FTIR) spectroscopy, Boehm titration method and zeta potential, it was found that the simple thermal oxidation of ND at 425 °C, increased the content of carboxylic acid of ND and accordingly the zeta potential of ND decreased considerably. Therefore, a series of oxidized NDs (OND) at various oxidation times and as-received untreated ND (UND) was used as adsorbents of MO and MB. The adsorption experiments exhibited that UND had large adsorption capacity, very fast adsorption kinetics and excellent selectivity for MO over MB. These results suggested that the adsorption tendency of UND toward anionic MO dye followed not only by electrostatic interactions but also via the chemical interaction caused by the strong hydrogen bond between the sulfonate groups of MO and the oxygen containing groups on the surface of UND. In contrast, ONDs exhibited higher adsorption capacity for cationic MB whose tendency toward MB increased by increasing the thermal oxidation time due to the promotion of the negative charge on the surface of OND leading to the higher electrostatic attraction. The adsorption rate of MB on ONDs was also very high. Kinetics data was well fitted with the pseudo- second-order model for most of the adsorbents. The adsorption selectivity analysis revealed that ONDs displayed more adsorption capacity for MB compared with MO which was also attributed to high electrostatic interactions of cationic dye with negative charges of ONDs. Finally, the release behavior of NDs was also demonstrated after soaking in ethanol and acetone.

Facile Synthesis of NaOH-modified Fishbone Charcoal (FBC) with Remarkable Adsorption towards Methylene Blue

Abstract This study has demonstrated the preparation of NaOH-FBC and investigated its potential application as an adsorbent to remove MB from aqueous solution. Adsorption Experiments of MB removal were carried out based on the parameters of initial pH, initial MB concentration, temperature and contact time. Results showed that the specific surface area of the NaOH-FBC reached up to 61.13m2/g. The experimental adsorption data were analyzed with Langmuir and Freundlich isotherm models. The kinetic adsorption models were also studied. By fitting the Langmuir adsorption isotherm model, the qmax of the NaOH-FBC was highly achieved as 605.82±9.09 mg/g, compared to 70.42±1.34 mg/g produced by the untreated FBC. The MB adsorption process using the untreated FBC was a non-spontaneous and endothermic process, which was well fitted with the pseudo-first-order kinetic model and Freundlich adsorption isotherm model. However, the MB adsorption process of the NaOH-FBC was a spontaneous and endothermic process, which was in accordance with the pseudo-second-order kinetic model and Freundlich adsorption isotherm model. Furthermore, with the increase of pH, temperature and contact time, the adsorption capacity of MB onto the FBC and NaOH-FBC were both increased. The adsorption results suggest the efficiency and potential of NaOH-FBC as a MB adsorbent.

One-pot preparation of MnO x impregnated cotton fibers for methylene blue dye removal.

Using natural cotton fibers (CF) as a matrix, a series of novel MnOx impregnated cotton fibers (designated as Mn-X@BCF) were prepared in this study through a one-pot sono-assisted KMnO4 reduction process with no additional reducers. The as-prepared Mn-X@BCF was covered by a uniform and dense layer of MnOx nanospheres (10–30 nm), the amount of which was significantly improved by CF pretreatment and linearly correlated with KMnO4 concentration. Specifically, when KMnO4 concentrations increased from 5 mmol L−1 to 100 mmol L−1, the impregnation ratios of MnOx on BCF increased from 0.34% to 14.98% accordingly. Mn-X@BCF showed substantial removal for the typical dye MB. Under the studied conditions, MB removal equilibrium was reached within 10 minutes and solution pH showed no significant influence over a wide pH range (2–11). MB adsorption by Mn-25@BCF obeyed the pseudo-second-order kinetic model and Langmuir model well. The calculated maximum adsorption capacity (Qm) of Mn-25@BCF was 46.3 mg g−1, close to the cumulative adsorption capacity (Qc 45 mg g−1) of MB determined during the eight cycles of adsorption. It was proposed that adsorption followed by partial oxidation was the main mechanism of MB removal by Mn-X@BCF. The as-prepared Mn-25@BCF has great potential as an efficient and low-cost material for dye wastewater treatment because of its inexpensive and renewable source of raw materials, fast MB removal kinetics, wide working pH range and easy solid–liquid separation.

Fabrication of three-dimensional porous β-cyclodextrin/chitosan functionalized graphene oxide hydrogel for methylene blue removal from aqueous solution

A three-dimensional porous β-cyclodextrin/chitosan functionalized graphene oxide hydrogel (3D-GO/CS/β-CD) was synthesized by a simple and facile chemical reduction method in the presence of sodium ascorbate which acted as a reducing agent, and its application as an adsorbent for MB removal was investigated. The unique 3D structure enabled the rapid reuse and recyclability of 3D-GO/CS/β-CD without a complicated filtration system. The adsorbent was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller (BET) analysis, and the results of the characterization indicated the successful synthesis of 3D-GO/CS/β-CD. The 3D-GO/CS/β-CD showed an ultrahigh adsorption capacity (1134mg/g) for MB. The investigation of the adsorption behavior demonstrated that the adsorption was well fitted with the pseudo-second-order model and Freundlich model. The simulation of the intra-particle diffusion model illustrated that both film diffusion and intraparticle diffusion were involved in the adsorption process. The thermodynamics analysis suggested that the adsorption process of MB onto 3D-GO/CS/β-CD was spontaneous and endothermic. Furthermore, the regeneration study showed that the 3D-GO/CS/β-CD can be reused in the wastewater treatment application. All these findings demonstrated that the 3D-GO/CS/β-CD could be a cost-effective and promising adsorbent for MB removal from the aqueous solution.

Chitosan-edible oil based materials as upgraded adsorbents for textile dyes

Biopolymer chitosan is a low cost, abundant, environmentally friendly, very selective and efficient anionic dyes adsorbent, being a promising material for large-scale removal of dyes from wastewater. However, raw chitosan (CS) is an ineffective cationic dyes adsorbent and its performance is pH sensitive, thus, CS modifications that address these issues need to be developed. Here, we report the preparation and characterization of two new CS modifications using edible oils (soybean oil or babassu oil), and their adsorption performance for two dyes, one anionic (remazol red, RR) and one cationic (methylene blue, MB). Both modifications extended the pH range of RR adsorption. The babassu oil modification increased adsorption capacity of the cationic dye MB, whereas the soybean oil modification increased that of RR. Such improvements demonstrate the potential of these two new CS modifications as adsorbent candidates for controlling dyes pollution in effluents.

Hydrogen titanate nanosheets with both adsorptive and photocatalytic properties used for organic dyes removal

Titanate nanomaterials have drawn increasing interests due to their special properties, such as ion-exchange performance and photo-activity. In this study, a hydrogen tianate nanosheet (H-TNS) was synthesized through a one-step hydrothermal method. The material shows both good adsorptive and photocatalytic properties, thus can firstly concentrate and then degrade organic dyes through combined adsorption and photocatalysis. H-TNS is a kind of 2D tri-titanate (H2Ti3O7) nanosheet with fine crystal structure, which composes of [TiO6] octahedron skeleton and interlayered H+. Ion-exchange between the dye cation and H+ in the interlayers is the primary adsorption mechanism. Moreover, protonation of titanate can enhance its photocatalytic activity due to the narrowed band gap energy (Eg) and improved visible light adsorption. H-TNS could quickly capture MB and RhB from solutions, with an equilibrium time of 180min. Langmuir model fitted well with the isotherm data (R2>0.99), and the simulated monolayer maximum adsorption capacity of MB and RhB was 81.5mg/g and 52.9mg/g, respectively. Furthermore, the adsorbed MB and RhB on H-TNS could be further photo-degraded under UV light, resulting in a final removal efficiency of 99.9% and 92.7% for the two dyes, respectively. In addition, H-TNS also could be efficiently reused over 5 cycles.

Synthesis of malachite@clay nanocomposite for rapid scavenging of cationic and anionic dyes from synthetic wastewater

Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic (Methylene Blue, MB) and anionic dyes (Congo Red, CR) from synthetic wastewater. Nanocomposite was characterized by TEM, SEM, FT-IR, EDS analysis and zeta potential. TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to 23nm. Various important parameters viz. contact time, concentration of dyes, nanocomposite dosage, temperature and solution pH were optimized to achieve maximum adsorption capacity. In the case of MB, removal decreased from 99.82% to 93.67% while for CR, removal decreased from 88.55% to 75.69% on increasing dye concentration from 100 to 450mg/L. pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range. Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes. Negative values of ΔG0 for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite. Nanocomposite showed 277.77 and 238.09mg/g Langmuir adsorption capacity for MB and CR respectively. Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone. The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.

Effects of cellulose carbonization on biomass carbon and diatomite composite

The biomass carbon and diatomite composite was prepared by hypoxia pyrolysis method, which adopted diatomite accompanied by cellulose as raw materials. The properties of carbonaceous samples were characterized by Thermal gravity-differential thermal analysis (TG-DTA), X-ray diffraction analysis (XRD), Scanning electron microscope analysis (SEM), Fourier transform infrared spectroscopy analysis (FT-IR), particle size analysis, Zeta potential analysis and MB adsorption capacity analysis. The XRD results showed that the crystallization temperature of opal phase was reduced nearly 350°C by cellulose carbonization in biomass carbon and diatomite composite. The SEM analysis showed that the porous morphology of diatomite was changed by cellulose carbonization at lower temperature. The FT-IR results showed that the absorption peaks of SiOSi around 462cm−1 and 1098cm−1 were significantly weakened as biomass carbon increased. The MB absorption capacity of biomass carbon and diatomite composite was significantly increased by cellulose carbonization, qe was in the range of 39.97–49.82mgg−1, thus the biomass carbon and diatomite composite which was environment friendly and inexpensive had the potential to be an excellent absorbent.

Evaluation on dye removal capability of didodecyldimethylammonium-bentonite from aqueous solutions

ABSTRACTThe removal efficiency of Reactive Blue 19 (RB19) by using surfactant-modified bentonite (MB) from aqueous solutions, and also textile wastewater samples was examined. Natural bentonite (NB) was firstly modified with didodecyldimethylammonium bromide (DDDAB) in order to increase the removal capacity of bentonite. MB was then characterized by Fourier Transformed Infrared Spectrophotometer (FTIR), x-ray diffractometry (XRD), x-ray fluorescence (XRF), Scanning Electron Microscope (SEM)/EDX, zeta potential, elemental, and thermal analysis techniques. The high adsorption capacity of MB was 407.7 mg g−1 at pH = 1.5 and 20°C. The adsorption of Reactive Blue 19 onto MB agreed with the pseudo-second-order kinetic and Langmuir isotherm models.

Studies on adsorption performance of carboxymethyl-β-cyclodextrin nano-cavities grafted onto polyacrylamide

A novel carboxymethyl-β-cyclodextrin grafted polyacrylamide (CM-β-CD-PAM) was successfully prepared and applied in the adsorption of MB molecules in aqueous solution. The adsorption performance of CM-β-CD-PAM for MB was investigated by changing pH values and temperature of dye solution. The results showed that CM-β-CD-PAM was an effective adsorbent and has high adsorption capacity for MB. The negative value of free energy change indicated that the adsorption of CM-β-CD-PAM for MB was spontaneous. The mechanism of adsorption was ascribed to the formation of inclusion complexes between MB molecules and nano-cavities of CDs from CM-β-CD-PAM, hydrogen bonding and electrostatic interactions between adsorbate-adsorbent.

Ordered Mesoporous Carbons as Novel and Efficient Adsorbent for Dye Removal from Aqueous Solution

Ordered mesoporous carbons (OMCs) were successfully synthesized by using hard template and soft template methods. These materials were characterized by XRD, TEM, and N2adsorption-desorption Brunauer-Emmett-Teller (BET). From the obtained results, it is revealed that the obtained OMCs samples showed high surface area (>1000 m2/g) with high pore volume, mainly mesopore volume (1.2–2.4 cm3/g). Moreover, OMCs samples had similar structure of the SBA-15 silica and exhibited high MB adsorption capacity withqmof 398 mg·g−1for OMCs synthesis with hard template and 476 mg·g−1for OMCs synthesis with soft template, respectively. From kinetics investigation, it is confirmed that MB adsorption from aqueous solution obeys the pseudo-second-order kinetic equation.

Ultrasound and microwave-assisted preparation of Fe-activated carbon as an effective low-cost adsorbent for dyes wastewater treatment

A and B are Langmuir isotherm and pseudo-second-order model. We conclude that MB adsorption capacity of Fe-activated carbon is bigger than raw activated carbon, indicating that Fe-activated carbon has better MB removal efficiency.

Monolithic porous rectorite/starch composites: fabrication, modification and adsorption

The monolithic rectorite/starch composites (PRSs) were fabricated by freezing the composite gels and exchanging ice with ethanol to obtain the porous structures. The rectorite layers were randomly oriented and covered with starch in the monolithic PRSs. Two modifications were treated without destroying the porous structures. Starch components were removed to obtain the calcinated PRSs (CPRSs); and starch components reacted with carbon disulfide to obtain the porous rectorite/starch xanthate composites (PRSXs). PRSs, CPRSs and PRSXs exhibited low density and high liquid adsorption due to the porous structures. CPRSs possessed the higher MB adsorption capacity than PRSs, because the resistance of starch on MB adsorption was eliminated. The chelation could form between xanthate groups and Pb (II), and improve the adsorption of Pb (II) of PRSXs. The maximum adsorption capacities could reach 277.0 and 180.8mgg−1 for MB by CPRS and Pb (II) by PRSX, respectively. Moreover, CPRS could be effectively recycled by burning away the adsorbed MB dye; while PRSX could be easily regenerated with ethylenediaminetetraacetic acid disodium salt (EDTA) solution. The modification of PRSs had the potential applications on the treatment of cationic contaminations in water.

One-pot synthesis of C18-functionalized core–shell magnetic mesoporous silica composite as efficient sorbent for organic dye

In this work, a facile one-pot strategy was proposed for the synthesis of C18-functionalized core–shell magnetic mesoporous silica composite (Fe3O4/mSiO2–C18). The Fe3O4/mSiO2–C18 composite, with an average size of 80nm and a functionalized mesoporous silica shell of about 30nm in thickness, has excellent adsorption ability toward methylene blue dye (MB) due to the large surface area (303m2g−1) and the abundant hydrophobic C18 groups. The adsorption equilibrium was achieved within 20min and the adsorption behavior of MB on Fe3O4/mSiO2–C18 composite fitted the pseudo-second-order kinetic model well (k2=1.29×10−2gmg−1min−1, qe=144.72mgg−1, ho=270.27mgg−1min−1 under 25°C and an initial MB concentration of 10mgL−1). Langmuir and Freundlich isothermal adsorption models can both be used to describe the adsorption process and the maximum Langmuir adsorption capacity of MB on Fe3O4/mSiO2–C18 at 25°C and pH 7.5 is 363.64mgg−1. Thermodynamic parameters show that the adsorption reaction is exothermic and spontaneous (ΔH0=−63.49kJmol−1, ΔG0=−7.80kJmol−1). Ionic strength and pH affected the adsorption slightly. In addition, the MB adsorbed sorbent can be readily separated from water solution by an external magnet because of the high magnetic saturation value (22.62emug−1). After being regenerated by treatment with acidic methanol, the sorbent could be reused for at least 5 cycles with a little decrease in adsorption capacity.

Effect of hydroxyl group of carboxylic acids on the adsorption of Acid Red G and Methylene Blue on TiO2

While TiO2 has generated great interest in the removal of organic pollutants in recent years, the effect of the surface chemical property of TiO2 on the adsorption performance is unclear. Here, TiO2 samples were prepared in succinic (without hydroxyl group), malic (with one hydroxyl group) and tartaric acid (with two hydroxyl groups) by hydrolysis method and labeled as SU-TiO2, MA-TiO2 and TA-TiO2, respectively. Their adsorption performance for anionic dye-Acid Red G (ARG) and cationic dye-Methylene Blue (MB) was investigated. The adsorption study indicates that the adsorption amount of ARG or MB was proportional to the alkalinity or the acidity, which is related to the number of hydroxyl group of the used acids, of the as-prepared TiO2. Therefore, SU-TiO2 displayed the largest adsorption capacity for ARG, while TA-TiO2 had the highest adsorption capacity for MB. Furthermore, TA-TiO2 can be reused at least 5 times without losing its adsorption capacity. The results indicate that the adsorption mechanism involves in the electrostatic interaction and the electron acceptor–donor interaction.

Fabrication of mesoporous Al-SBA-15 as a methylene blue capturer via a spontaneous infiltration route

Mesoporous Al-SBA-15 materials were synthesized via a facile solvent-free method and they present much higher MB adsorption capacity than the siliceous SBA-15.

Assessment of Urtica as a low-cost adsorbent for methylene blue removal: kinetic, equilibrium, and thermodynamic studies

AbstractMethylene blue (MB) removal using eco-friendly, cost-effective, and freely available Urtica was investigated. The morphology of the adsorbent surface and the nature of the possible Urtica and MB interactions were examined using SEM analysis and the FTIR technique, respectively. Various factors affecting MB adsorption such as adsorption time, initial MB concentration, temperature, and solution pH were investigated. The adsorption process was analysed using different kinetic models and isotherms. The results showed that the MB adsorption kinetic follows a pseudo-second-order kinetic model and the isotherm data fit the Langmuir isotherm well. Thermodynamic parameters, such as ΔG°, ΔH°, and ΔS°, were also evaluated, and the results indicated that the adsorption process is endothermic and spontaneous in nature. The MB adsorption capacity of Urtica was found to be as high as 101.01 mg g

Converting real-world mixed waste plastics into porous carbon nanosheets with excellent performance in the adsorption of an organic dye from wastewater

Real-world mixed waste plastics were converted into PCNSs, which exhibited fast adsorption, unprecedented adsorption capacity and excellent recyclability for MB.

Synthesis, structure and photocatalytic activity of calcined Mg-Al-Ti-layered double hydroxides

Mg-Al-Ti layered double hydroxides (LDH), consisting of di-, tri- and tetra-valent cations with different Al3+/Ti4+ ratio, have been synthesized by co-precipitation which was demonstrated as efficient visible-light photocatalysts. The structure and chemical composition of the compound were characterized by PXRD, FT-IR, SAA, N2 adsorption-desorption isotherms, and DSC techniques. It is found that no hydrotalcites structure were formed for Ti4+/(Ti4++Al3+)>0.5 and the substitution of Ti(IV) for Al(III) in the layer increases the thermal stability of the resulting LDH materials. The calcined sample containing titanium showed relatively high adsorption capacity for MB as compared to that without titanium. Results show that the pseudo-second-order kinetic model and the Langmuir were found to correlate the experimental data well. The photocatalytic activity was evaluated for the degradation of the methylene blue. The photocatalytic activity increased with the increase of the Al/Ti cationic ratio. 71% of the dye could be removed by the Mg/Al/Ti-LDH with the cationic ratio Al/Ti=0 : 1 and calcined at 500 °C.