Adsorption Of Reactive Blue 19 Research Articles

Reactive Blue 19 Adsorption on Activated Carbon From Pumpkin (Cucurbita Pepo) Seed Waste: Kinetic, Isotherm and Thermodynamic Studies

In this study, the removal of Reactive Blue 19 dyestuffs in aqueous systems was investigated by adsorption method using activated carbon obtained from the pumpkin seed waste. Activated carbon obtained from pumpkin seed waste functionalized with ZnCl2 was used as an absorbent. Pumpkin seed hydrochar was characterized by FT-IR, SEM, TGA-DTA, BET, and XPS. In the experimental stages, the adsorption equilibrium time was determined as 45 minutes, the adsorbent dosage was 0.8 g and the optimum pH was 6.0. After this step, the adsorption parameters of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms were investigated. It has been pointed out that the adsorption process fits better with the Freundlich isotherm model, and the adhesion occurs in a multilayered manner and on a heterogeneous surface. Freundlich and Dubinin-Radushkevich isotherms support that the bonding mechanism is realized by physical interactions. When the kinetic data were evaluated, it was found to be compatible with the pseudo-second-order kinetic model. The thermodynamic parameters of adsorption indicate that the system is endothermic, and the adsorption of Reactive Blue 19 on activated carbon is a spontaneous process.

Removal of reactive blue 19 from simulated wastewater using Solanum melongena stalk/MWCNTs: thermodynamics, kinetic, equilibrium and regeneration potentials

In the present study, a nanocomposite was prepared for the removal of dye from the aqueous phase. In this regard, multi-walled carbon nanotubes (MWCNTs) were anchored on the stalk of Solanum melongena (SMB) to obtain a robust adsorbent with the capacity to eliminate reactive blue 19 (RB19) using the batch adsorptive processes. Solanum melongena stalk decorated with MWCNTs (SMC) and SMB were characterized using Thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET), Field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR) analysis. With the exception of solution pH, an increase in contact time, adsorbent dose, initial RB19 concentration, and solution temperature were noticed to elevate the uptake potential of SMB and SMC. Kinetic experimental data for SMB and SMC were consistent with the pseudo-second-order and Elovich model, respectively. The experimental isotherm data obtained for SMB and SMC were best expressed by Freundlich and Langmuir models, respectively. After the fifth adsorption–desorption cycle, SMC exhibited 52% of adsorption efficiency. Hence, SMC can be an auspicious candidate for the efficient adsorption of RB19.

Three-dimensional lignin-based polyporous carbon@polypyrrole for efficient removal of reactive blue 19: A synergistic effect of the N and O groups

Reactive blue 19 is one of the abundant carcinogens commonly used in industrial applications. This study transformed industrial lignin into a lignin-based polyporous carbon@polypyrrole (LPC@PPy) by a hydrothermal-activation-in situ polymerization strategy for removal of reactive blue 19. The hydrothermal reaction and polypyrrole polymerization provide abundant O and N groups, and the pore-making process promotes the even distribution of O and N groups in the 3D pore of LPC@PPy, which is favorable for the adsorption of reactive blue 19. The adsorption capacity of LPC@PPy for reactive blue 19 is 537.52 mg g−1, which is 2.04 times the performance of LPC (only hydrothermal and activation process, only have O groups) and 3.36 times that of LC (direct lignin activation, lack of O and N groups). After 8 cycles, LPC@PPy still maintained a high adsorption capacity of 92.14 % for reactive blue 19. In addition, this study found that N and O groups in the material played an important role in adsorption, mainly pyridinic–N, C–OH, –COOR, –C–O– and CC. This work provides a new strategy for the removal of reactive blue 19 and determines the groups that mainly interact with reactive blue 19, which provides a new reference for adsorption, catalysis and related fields.

Hybrid multifunctional biocomposite of chitosan grafted benzaldehyde/montmorillonite/algae for effective removal of brilliant green and reactive blue 19 dyes: Optimization and adsorption mechanism

Herein, a novel hybrid multifunctional biocomposite of chitosan grafted-benzaldehyde/montmorillonite/algae (CHS-BZ/MT/AL) was designed and applied for the highly efficient removal of brilliant green (BG) and reactive blue 19 (RB19) dyes from an aquatic environment. The influence of three processing factors, including CHS-BZ/MT/AL dose (0.02–0.08 g), pH solution (4–9), contact time (5–30 min), and their interactions on the removal rate of BG and RB19 dyes, was examined using the response surface methodology integrated with Box-Behnken design (RSM-BBD). The experimental outcomes of equilibrium and kinetic investigations showed that the adsorption of BG and RB19 dyes on CHS-BZ/MT/AL obey pseudo-second-order and Langmuir models. The CHS-BZ/MT/AL possesses a maximum adsorption capability of 899.5 mg/g for BG and 213.6 mg/g for RB19. The proposed mechanism of BG and RB19 adsorption in the lighting of the CHS-BZ/MT/AL's characterization is mainly included several interactions like electrostatic forces, π-π stacking, n-π stacking, and H-bonding. The current work indicates that the synthesized CHS-BZ/MT/AL with a distinct structure and excellent adsorptive characteristics could be employed to remove hazardous cationic and anionic dyes from industrial wastewater.

Adsorption Behaviors of Cationic Methylene Blue and Anionic Reactive Blue 19 Dyes onto Nano-Carbon Adsorbent Carbonized from Small Precursors.

In this work, an innovative nano-carbon material (N-CM) adsorbent was reported for exploring its adsorption behaviors toward cationic methylene blue (MB) and anionic reactive blue 19 (RB19) pollutants. The proposed N-CM was synthesized by a one-step solvothermal treatment of citric acid and zinc gluconate small precursors. N-CM consists of nanosheets that have an advantageous specific surface area, large sp2/sp3 hybridized domains, and abundant nitrogen/oxygen-containing surface functional groups. The synergistic effects of these features are conducive to the MB and RB19 adsorption. Different from anionic RB19 adsorption (79.54 mg/g) by the cooperative π-π stacking and hydrogen bonding, cationic MB adsorbed onto N-CM mainly by the electrostatic attraction at the natural pH solution (> pHpzc), with an adsorption capacity up to 118.98 mg/g. Interestingly, both MB and RB19 adsorption conformed to the pseudo-second order kinetic (R2 ≥ 0.995) and Langmuir isothermal (R2 ≥ 0.990) models, accompanied by similar maximum monolayer adsorption capacities of 120.77 and 116.01 mg/g, respectively. Their adsorption processes exhibited spontaneously endothermic characteristics. Moreover, N-CM showed superior selective capability toward MB in different mixed dye systems, with high removal efficiencies of 73–89%. These results demonstrate that the high-performance carbon adsorbent prepared from small precursors via low-temperature carbonization shows great potentials in wastewater treatment.

Reactive blue 19 adsorption behaviors of magnesium hydroxide modified biochar derived from the traditional Chinese medical residual

This study examined the reactive blue 19 (RB-19) adsorption behaviors of magnesium hydroxide modified biochar (MBC) derived from the traditional Chinese medical residual. The obtained MBC was characterized using Scanning Electron Microscope (SEM), Fourier Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The static adsorption experiment was carried out to investigate the adsorption properties. The results indicated that pH 4 was best for the adsorption removal of RB-19 in the pH range of 4–9. Compared with the pseudo-first-order model and Elovich model, the pseudo-second-order equation was best to describe the adsorption process (R2 > 0.995). The Langmuir model was better than the Freundlich model to fit the experimental data (R2 > 0.990). The intra-particle diffusion model showed that film diffusion and intra-particle diffusion were involved in the adsorption process. Thermodynamic parameters showed that the RB-19 adsorption by MBC was spontaneous and endothermic. The adsorption mechanism might include electrostatic interaction, pore filling, and hydrogen bond, and the MBC was a promising adsorbent.

Efficient adsorption removal of anionic dyes by an imidazolium-based mesoporous poly(ionic liquid) including the continuous column adsorption-desorption process

The mesoporous poly(N,N′-methylene-bis(1-(3-vinylimidazolium)) chloride), labeled as PDVIm-Cl, with double anions (Cl−) and low monomer molecular weight was synthesized and applied in the adsorption of anionic dyes (acid orange 7 (AO7), sunset yellow (SY), reactive blue 19 (RB19), congo red (CR)). Due to the mesoporous structure, abundant Cl− and positively charged imidazole rings, the poly(ionic liquid) (PIL) exhibited superior adsorption ability towards anionic dyes. What is more, the RB19 adsorption by PDVIm-Cl could achieve the highest capacity (2605 ± 254 mg g−1) which was nearly twice higher than the maximum adsorption capacity of the previously reported materials. All the adsorption kinetic data and isotherms fitted well with the pseudo second-order model and Langmuir-Freundlich model. To better explore the practical potential of the PIL for dye adsorption, the adsorption under different pH values and column adsorption performances were also evaluated. Results showed that PDVIm-Cl exhibited high removal efficiencies for anionic dyes over a wide pH range (2−10). Also, the great reusability could be well demonstrated by the achievable continuous column adsorption-desorption process. It is worth mentioning that the regeneration could be realized with very little desorbent which was far less than the adsorption volume flowing through the column and the desorption efficiency was well maintained after three consecutive cycles. At last, the adsorption mechanism was explored by experiments combined with quantum chemical calculations and showed anionic dyes adsorption by PDVIm-Cl was a joint process dominated by the ion exchange, electrostatic interaction, hydrogen bond and π-π stacking.

Efficiency of activated carbon prepared from scrap tires magnetized by Fe3O4 nanoparticles: characterisation and its application for removal of reactive blue19 from aquatic solutions

ABSTRACT Huge quantities of different dyes are generated by various industries such as cosmetic, leather, printing and textile and food. This study aimed to generate and apply tire-derived activated carbon magnetised with the Fe3O4 nanoparticles (MAC) for the removal of reactive blue 19 (RB19) dye from aquatic solutions. FE-SEM, VSM, XRD, FTIR and BET analyses were used to determine MAC properties. Under optimal conditions of pH 3, the initial concentration of dye 100 mg/L, the composite dose 1 g/L and the reaction time of 45 min, the removal efficiency for RB19 was 93.22%. Isotherm findings illustrated that RB19 adsorption onto the MAC followed the Langmuir model. Moreover, the absorption kinetics is well interpreted by the pseudo-second-order model in low scrutinised concentrations. The SBET and total pure volume for the MAC were 421.11 m2 g−1 and 0.467 cm3 g−1. Under the optimum conditions, maximum adsorption capacity of the MAC in Langmuir model enhanced to the amount of 119.05 mg/g. Also, the reusability (with NaOH) of the MAC revealed about 21% decreases in the removal efficiency within five consecutive runs. It is concluded that the application of the magnetised activated carbon due to its high efficiency in removing RB19 from laboratory and actual samples can be evaluated in future studies to be utilised in real scales.

Adsorption of sulfamethoxazole and reactive blue 19 using graphene oxide modified with imidazolium based ionic liquid

Abstract The adverse effect of organic pollutant such as dyes and pharmaceuticals on aquatic life is of great concern. Thus, in this work, a highly hydrophobic composite made up of graphene oxide (GO) and ionic liquid (IL) was synthesized for the removal of reactive blue 19 (RB19) and sulfamethoxazole (SMZ). GO was first synthesized with the Tour method and the long chain C14 imidazolium IL through a green technique. 13C, 1H NMR and HRMS were used to determine the structure of the synthesized ionic liquid. GO-IL was produced by co-precipitation of GO and IL. FTIR confirmed the presence of the new functional groups on GO-IL. XRD confirmed GO synthesis and the crystalline nature of GO-IL. SEM and TEM confirmed the sheet like morphology of GO and GO-IL and showed enmeshment of IL in the lateral GO sheets. The experimental conditions for the adsorption of RB19 on GO was at 25℃, with pH 2.04 and 3 g/L dose of adsorbent. For GO-IL the optimum dose of 0.5 g/L and 0.9 g/L at pH of 4.01 and 6.28 for RB19 and SMZ adsorption, respectively. Maximum adsorption ( q m ) of 27.25 mg/g and 416.7 mg/g were obtained for adsorption of SMZ and RB19, respectively on GO-IL. Thermodynamic studies revealed adsorption was exothermic and the data obtained supported the pseudo-second order kinetic model, and both Langmuir and Freundlich isotherm models. The adsorption mechanism was attributed to hydrophobic effects, hydrogen bonding, electrostatic and π - π interaction. Regeneration studies showed adsorbent reusability. This is the first report that shows the adsorption study of RB19 and SMZ on GO modified with a C14 long chain imidazolium IL. The hybrid adsorbent improved dispersion in aqueous medium, thus enhancing efficiency and cost effectiveness for the removal of RB19 and SMZ. This study helps to provide mechanistic insight into the adsorption process of RB19 and SMZ.

Adsorption of reactive dyes on lignocellulosic waste; characterization, equilibrium, kinetic and thermodynamic studies

This study researched the use of the easily obtainable and economic agricultural waste of corn silk (CS) for removal of Reactive Blue 19 (RB19) and Reactive Red 218 (RR218) dyes with the adsorption process. Lignin, holocellulose, α-cellulose, thermogravimetric analysis (TGA), fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analyses were completed with the aim of determining the physical and chemical characteristics of the lignocellulosic adsorbent and ash content was determined. Additionally, the contact duration of adsorption, concentration of dye, temperature and pH parameters were investigated with equilibrium, kinetic and thermodynamic parameters determined to research the mechanism of adsorption. For both reactive dyes the removal efficiency is linked to the effective pH. With initial dye concentration of 200 mg/L, temperature of 25 °C, and adsorbent concentration of 0.25 g/50 mL fixed, maximum removal efficiency was 99% obtained at pH 2.0. The study calculated 6 different two-parameter isotherms and according to the best R2 value, the Temkin and Freundlich isotherm models were selected. The maximum capacity of CS for adsorption of RB19 and RR218 was 71.6 mg/g and 63.3 mg/g at adsorbent dose of 0.25 g/50 mL for initial dye concentration of 500 mg/L, pH 2.0 and 25 °C. According to the kinetic model results calculated with the aid of experimental data, a good adsorption process occurred. Thermodynamic parameters like enthalpy variation (ΔH0), entropy variation (ΔS0) and free Gibbs energy variation (ΔG0) were calculated with the aid of data obtained at different temperatures. As temperature increased dye adsorption was observed to increase confirming this event is endothermic.

Adsorption of Reactive Blue 19 from aqueous solution by chitin nanofiber-/nanowhisker-based hydrogels.

Physical hydrogels prepared from partially deacetylated chitin nanofibers/nanowhiskers (DEChNs) were prepared and evaluated as a new adsorbent for Reactive Blue 19 (RB19) solutions. The effects of pH, initial dye concentration, contact time and temperature were investigated. The optimum pH value for the adsorption experiments was found to be 1.0; as pH increases, the dye adsorption capacity decreases gradually. The adsorption of RB19 onto partially deacetylated chitin nanofiber-/nanowhisker-based hydrogels (DEChNs-Gels) was relatively fast, as the equilibrium could be reached in almost 20 min. The maximum adsorption capacity was found to be 1331 mg g−1 at pH = 1 (degree of deacetylation (DDA) = 23%, dye concentration = 1000 mg L−1), considering the practical applications, the adsorption capacity in pH = 5 (838 mg g−1) was believed to have more practical significance. A pseudo-second-order kinetics model agreed very well with the experimental results. Equilibrium data also fitted well to the Freundlich adsorption isotherm model in this study. The DEChNs-Gels exhibited a high efficiency for removing RB19 from aqueous solutions as a result of their nanofibrillar network and excellent pore structure accompanied by the presence of amino groups. Even when the DDA was lowered to 15%, the adsorption capacity reached 940 mg g−1 due to its nanostructural assembly of nanofibers/nanowhiskers, which showed great advantages compared to highly deacetylated chitosan-based adsorbents (DDA > 70%). Considering the issue of environmental protection and adsorption efficiency, DEChNs-Gels have become a potential substitute for chitosan-based adsorbents due to the milder deacetylation process and superior performance, making this material an attractive adsorbent for textile dyes.

Adsorption of Reactive Blue 19 on coconut shell and bamboo activated carbons

Abstract: Kinetics and isotherms of Reactive Blue 19 adsorption on two kinds of granular activated carbons from coconut shell and bamboo were determined in this study. These activated carbon are micropore materials with specific surface areas of 687 and 425 m2/g, respectively. Experimental data shows that equilibrium times are the same for both kinds of activated carbon when ininital concentration of the dye is 40 mg/L. However, maximum absorption capacity of bamboo activated carbon is about 10 times higher than that of coconut shell. This results reveals that adsorption site density on the surface plays a more important role than specific surface area. 

The Adsorption of Reactive Blue 19 Dye onto Cucurbit[8]uril and Cucurbit[6]uril: An Experimental and Theoretical Study.

The adsorption behavior and mechanism of Reactive Blue 19 (RB19) on cucurbit[6]uril (CB[6]) and cucurbit[8]uril (CB[8]) were investigated. The adsorption isotherm data obtained at different temperatures were fitted well to the Langmuir isotherm, and according to this model, CB[8] and CB[6] exhibited maximum monolayer adsorption capacities of 714.29 and 100.5 mg/g, respectively, at 298.15 K. The adsorption thermodynamic functions ΔG, ΔH, and ΔS were evaluated and revealed that RB19 adsorption onto CB[8] and CB[6] is a spontaneous and enthalpy-driven process. The adsorption process was determined to follow pseudo-second-order kinetics, indicating that chemisorption dominates the adsorption process. Fourier tranform IR spectroscopy, thermogravimetric analysis, and density functional theory (DFT) calculations revealed that the formation of an inclusion complex is the main driving force of adsorption. The phenyl and sulfone moieties of RB19 reside inside the cavity of CB[8], but because of the small cavity, only the sulfone of RB19 resides inside the cavity of CB[6]. Time-dependent DFT calculations revealed that all of the absorption bands of RB19 derive from π → π* transitions, while for the adsorption product of CB[8], the bands located at 590 and 287 nm derive from π → π* transitions and the bands located at 254 and 202 nm mainly derive from intermolecular charge transfer (ICT).

Modeling and optimizing of adsorption removal of Reactive Blue 19 on the magnetite/graphene oxide nanocomposite via response surface methodology

AbstractIn this study, magnetite/graphene oxide (MGO) nanocomposite was prepared and applied for adsorption removal of Reactive Blue 19 (RB19). Optimization and modeling of the removal of RB19 using MGO were performed through the response surface methodology (RSM) based on central composite design (CCD). The MGO nanocomposite was synthesized by coprecipitation method. The structure and morphology of the prepared nanocomposite were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller analysis and vibrating sample magnetometer (VSM). Important factors influencing the adsorption of RB19 including pH, initial concentration of RB19, adsorbent dosage, and contact time were considered as input variables for RSM. The analysis of variance showed a high correlation coefficient (R2 = 0.954) between experimental and predicted responses. The removal efficiency of dye was more than 99% at the optimum condition proposed by RSM. Furthermore, ...

Removal of an anionic reactive dye from aqueous solution using functionalized multi-walled carbon nanotubes: isotherm and kinetic studies

AbstractIn this research, the adsorption process of Reactive Blue 19 (RB19) as an anionic dye onto functionalized multi-walled carbon nanotubes (f-MWCNTs) was studied. For this purpose, four parameters including agitation time, adsorbent dose, initial dye concentration, and pH were examined. N2 adsorption isotherms and Fourier transform infrared spectroscopy were used to characterize f-MWCNTs. Four isotherm and four kinetic models including two diffusion models were applied to comprehensively investigate the RB19 adsorption using f-MWCNTs. It was found that the adsorption follows Langmuir and Temkin equilibrium models with a maximum adsorption capacity of 217.39 mg g−1. The adsorption process best fitted to pseudo-second-order kinetic model and by applying diffusion models, the predominant rate-limiting step was found to be physisorption during the liquid film diffusion.

Adsorption of Reactive Blue 19 from Aqueous Solution by Carbon Nano Tubes: Equilibrium, Thermodynamics and Kinetic Studies

Adsorption of Reactive Blue 19 from Aqueous Solution by Carbon Nano Tubes: Equilibrium, Thermodynamics and Kinetic Studies

Removal of Reactive Blue 19 dye from Aqueous Solution Using Natural and Modified Orange Peel

Orange peel (OP) exhibits a sorption capacity towards anionic dyes such as reactive blue 19 (RB19). Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant was used to modify the surface nature of OP to enhance its adsorption capacity for anionic dyes from an aqueous solution. Four adsorbents were investigated: the OP, sodium hydroxide-treated OP (SOP), CTAB-modified OP and CTAB-modified SOP. The physical and chemical properties of these sorbents were determined using nitrogen adsorption at 77 K and by scanning electron microscope and Fourier transform infrared spectroscopy techniques. The adsorption of the RB19 dye was assessed with these sorbents at different solution pH levels and temperatures. The effect of the contact time was considered to determine the order and rate constants of the adsorption process. The adsorption data were analyzed considering the Freundlich, Langmuir, Elovich and Tempkin models. The adsorption of RB19 by the assessed sorbents is of the chemisorption type following pseudo-first-order kinetics. CTAB modification brought about a significant increase in RB19 adsorption, which was ascribed to the grafting of the sorbent with a cationic surfactant.

Tubular structured ordered mesoporous carbon as an efficient sorbent for the removal of dyes from aqueous solutions

Tubular structured ordered mesoporous carbon CMK-5 was investigated for the adsorption of the industrial dyes reactive blue 19, acid red 57 and fuchsin basic in aqueous solutions at room temperature. It was found that CMK-5 exhibits an ultrahigh adsorption rate and superior adsorption capacities for these dyes. Its maximum adsorption capacities for reactive blue 19, acid red 57 and fuchsin basic were 733, 1131 and 1403 mg g −1, respectively, and significantly greater than other literature reported results on porous carbons. Following adsorption of reactive blue 19, CMK-5 carbon could be regenerated by either ethanol extraction or thermal annealing at 600 °C, reaching ∼51% and ∼77%, respectively of the adsorption capacity of the original carbon. For comparison, ordered mesoporous carbon CMK-3 (rod structure), polymer based disordered mesoporous carbon, and steam and CO 2 activated commercial coconut carbons were investigated for the adsorption of reactive blue 19. The fast adsorption rate of CMK-5 carbon is due to its unique properties of tubular mesostructure, bimodal mesopore system and high surface area. In the case of requiring emergency removal of large amount of dyes in aqueous solution, CMK-5 would be an ideal choice.

Removal of azo and anthraquinone reactive dyes from industrial wastewaters using MgO nanoparticles

In the present investigation, a porous MgO powder was synthesized and tested for the removal of dyes from aqueous solution. The size of the MgO particles was in the range of 38–44 nm, with an average specific surface area of 153.7 m 2/g. Adsorption of reactive blue 19 and reactive red 198 was conducted to model azo and anthraquinone dyes at various MgO dosages, dye concentrations, solution pHs and contact times in a batch reactor. Experimental results indicate that the prepared MgO powder can remove more than 98% of both dyes under optimum operational conditions of a dosage of 0.2 g, pH 8 and a contact time of 5 min for initial dye concentrations of 50–300 mg/L. The isotherm evaluations revealed that the Langmuir model attained better fits to the experimental equilibrium data than the Freundlich model. The maximum predicted adsorption capacities were 166.7 and 123.5 mg of dye per gram of adsorbent for RB 19 and RR 198, respectively. In addition, adsorption kinetic data followed a pseudo-second-order rate for both tested dyes.

Modification of bentonite with a cationic surfactant: An adsorption study of textile dye Reactive Blue 19

The utilization of modified bentonite with a cationic surfactant (dodecyltrimethylammonium (DTMA) bromide) as an adsorbent was successfully carried out to remove a synthetic textile dye (Reactive Blue 19 (RB19)) by adsorption, from aqueous solutions. Batch studies were carried out to address various experimental parameters such as pH, contact time and temperature. The surface modification of bentonite with a surfactant was examined using the FTIR spectroscopic technique and elemental analysis. Effective pH for the adsorption of RB19 onto DTMA–bentonite was around 1.5. The Langmuir isotherm model was found to be the best to represent the equilibrium with experimental data. The maximum adsorption capacity ( q max) has been found to be 3.30 × 10 −4 mol g −1 or 206.58 mg g −1. The thermodynamic study indicated that the adsorption of RB19 onto DTMA–bentonite was favored with the negative Gibbs free energy values. The pseudo-second-order rate equation was able to provide the best description of adsorption kinetics and the intraparticle diffusion model was also applicable up to 40 min for the adsorption of RB19 onto DTMA–bentonite.