Dubinin-Radushkevich Adsorption Isotherm Research Articles

Removal of Acid Blue 25 from Aqueous Media by Magnetic-SBA-15/CPAA Super Adsorbent: Adsorption Isotherm, Kinetic, and Thermodynamic Studies

In this study, SBA-15 mesoporous silica was synthesized, magnetized, and then functionalized with cross-linked poly(acrylic acid) (CPAA) polymer, and the resulting adsorbent (Magnetic-SBA-15/CPAA) was used to remove Acid Blue 25 from aqueous media. X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller method, and vibrating sample magnetometry were used in this study. The effective parameters on dye removal, including pH, contact time, temperature, and adsorbent dosage were investigated and optimized. The optimum condition was pH = 2, adsorbent dosage of 0.025 g, and contact time of 60 min at 25 °C. UV–vis spectrophotometer was used to determine the amount of residual dye in solution. To determine the type of adsorption isotherm, the Langmuir, Freundlich, Tempkin, and Dubinin–Radushkevich adsorption isotherm equations were used. Pseudo-first-order and pseudo-second-order models were used to determine the k...

Equilibrium and kinetic studies of the adsorption of acid blue 9 and Safranin O from aqueous solutions by MgO decked FLG coated Fuller's earth

MgO decked few layer Graphene Coated Fullers' Earth (MgO-FLG-FE) is prepared by microwave irradiation and tested as adsorbent to remove Acid Blue 9 (AB9) and Safranin O (SO) dye from aqueous solutions. MgO-FLG-FE was characterized by FTIR, XRD, FESEM, HRTEM, RAMAN, and BET. The adsorbent dose required for the maximum removal of AB9 and SO dyes are 1.0 g and 0.08 g which is in very low quantity compared with FE. The contact time to achieve equilibrium is 120 min in both the dyes. Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms are applied to understand the adsorption mechanism for both the dyes in aqueous solutions. The uptake of AB9 and SO dye by MgO-FLG-FE is best explained by Langmuir adsorption isotherm. The adsorption capacities of MgO-FLG-FE for AB9 and SO are 37.7 mg/g and 201.1 mg/g respectively when compared with Fuller's Earth (36.7 mg/g and 131.19 mg/g). The adsorbent capacity of FE was enhanced by coating with very small amount of MgO decked FLG. The Pseudo-second order equation is best explained through the adsorption kinetics in this study.

Synthesis of novel magnetic nano-sorbent functionalized with N-methyl-D-glucamine by click chemistry and removal of boron with magnetic separation method

Click chemistry refers to a group of reactions that are fast, simple to use, easy to purify, versatile, regiospecific, and give high product yields. Therefore, a novel, efficient magnetic nano-sorbent based on N-methyl-D-glucamine attached to magnetic nanoparticles was prepared using click coupling method. Its boron sorption capacity was compared with N-methyl-D-glucamine direct attached nano-sorbent. The characterization of the magnetic sorbents was investigated by several techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, dynamic light scattering, thermogravimetric analysis, Fourier transform infrared spectrophotometer, and vibrating sample magnetometer. The boron sorption capacity of sorbents was compared by studying various essential factors influencing the sorption, like sorbate concentration, sorbents dosage, pH of the solution, and contact time. Langmuir and Freundlich and Dubinin-Radushkevich adsorption isotherms models were applied. Percent removal and sorption capacities efficiencies of sorbents obtained with direct and click coupling are found to be 49.5%, 98.7% and 6.68 mg/g, 13.44 mg/g respectively. Both sorbents have been found to be compatible with Langmuir isotherm, and the boron sorption kinetics conforms to the pseudo second order kinetics. The reusability study of sorbents was carried out five times for boron sorption and desorption.

Fabrication of magnetite-functionalized-graphene oxide and hexadecyltrimethyl ammonium bromide nanocomposite for efficient nanosorption of sunset yellow

A novel magnetic nanocomposite based on magnetite nanoparticles-functionalized-graphene oxide and hexadecyltrimethyl ammonium bromide has been synthesized (MAGO-CTAB) by a facile route for efficient, fast and sensitive binding with Sunset Yellow (SY). The MAGO-CTAB (27 ± 3 nm) has been successfully characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and vibrating sample magnetization techniques. The influences of different experimental parameters on the % SY removal efficiency were fully investigated. The adsorption rates of SY by MAGO-CTAB were conducted by fitting the experimental data to four kinetic models. Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D–R) adsorption isotherms were applied to study SY removal. The adsorption-desorption stability performance of the novel magnetic nanosorbent was evaluated and confirmed after 5 cycles. The designed MAGO-CTAB was successfully utilized for removal of SY from different food and soft drink samples with excellent recoveries values (98–103%).

Bio-composites for the sorption of copper from aqueous solution: A comparative study

Metal cleaning and plating baths, pulp, paper board mills, printed circuit board and wood pulp production, fertilizer industry etc. are releasing copper into the environment and seriously affecting the quality of drinking water. Even minute quantity of copper (1.3 ppm) in water is detrimental to biota. Therefore, abundantly available poultry and agricultural wastes are tested as adsorbents for the removal of copper leading to sustainable management of wastes and improving the quality of water. Sorption capacities of chitosan-Gallus domesticus eggshell, chitosan-Dromaius novaehollandiae eggshell (CH-GDES, CH-DNES) and chitosan-Dromaius novaehollandiae feather (CH-DNF) composites were first evaluated for copper removal from aqueous solution by ‘one variable at a time’ method, and further experiments were carried out by a three level full factorial design of Response Surface Methodology (RSM). The percent removal of copper by the composites increased with the increase in contact time and the kinetics best fitted to the pseudo - second order model. The optimum pH of the aqueous solution was found to be 6 for the removal of copper for all the three composites. The experimental data of initial metal ion concentration was fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich adsorption isotherm models, and the better suited is Langmuir's isotherm model. Chitosan-Gallus domesticus eggshell composite showed the highest metal uptake potential of copper (qmax 56.49 mg/g). Thermodynamically, copper adsorption onto the bio-composites is inferred as spontaneous, irreversible and endothermic in nature. Characterization of the adsorbents by SEM-EDS, FTIR, XRD and BET, before and after adsorption of copper, revealed that the sorption is due to the mechanisms of chemisorption, ion exchange and/or complexation. The adsorbent pads/filters made of natural renewable biopolymer composites like CH-GDES/CH-DNES/CH-DNF, can be placed at the source to prevent bulk water pollution with copper and maintain the concentration well below the permissible limits in the ground water.

Carbon composite lignin-based adsorbents for the adsorption of dyes

Carbon composite lignin-based adsorbent were prepared through hydrothermal method with glucose as carbon source, calcium lignosulfonate and triethylene tetramine as raw materials, respectively. The optimum synthesis conditions were determined by investigating the addition of carbon and triethylene tetramine. The adsorbent was used for the adsorption of azo dyes Congo red and Eriochrome blue black R, and the five factors affecting the adsorption were discussed, including pH of dyes, initial concentration, adsorption time, adsorption temperature and adsorbent dosage. The corresponding adsorption mechanism such as pseudo first order kinetics, pseudo second order kinetics, intraparticle diffusion, Langmuir adsorption isotherm, Freundlich isotherm, Temkin isotherm, Dubinin-Radushkevich adsorption isotherm, thermodynamics were also studied. When the dye concentration is 40 mg L−1, Congo red and Eriochrome blue black R dye removal rates reach 99%. Moreover, the adsorption process of two kinds of dyes follow the pseudo second order kinetics and the Langmuir adsorption isotherm.

Focus on adsorptive equilibrium, kinetics and thermodynamic components of petroleum produced water biocoagulation using novel Tympanotonos Fuscatus extract

Abstract Adsorptive component of produced water (PW) coagulation using Tympanotonos Fuscatus coagulant (TFC) was studied. Influence of the following parameters: pH, coagulant dose, settling time, and temperature were investigated. The functional group, crystalline nature, morphological observation and thermal characteristics of the sample were evaluated. Equilibrium data were analyzed using Langmuir, Freundlich, Temkin, Frumkin, and Dubinin-Radushkevich (D-R) adsorption isotherms. The kinetics data were fitted to reversible first order, pseudo-first-order, pseudo-second-order, elovich, intra-particle diffusion and Boyd kinetic models. Adsorption Gibbs energy, enthalpy and entropy were evaluated. Equilibrium data best fitted the Langmuir isotherm (R2 > 0.99; X2

Equilibrium and kinetic adsorption study of aqueous basic dye solutions using waste foundry sand

The aim of this study is to evaluate adsorption kinetics, isotherms and thermodynamic parameters of crystal violet (CV) and methylene blue (MB) dyes from aqueous solution using waste foundry sand. Adsorption studies were carried out at different initial dye concentrations (12.5-400 mg l−1), contact time (5-240 min), pH (3.0-9.0), sorbent doses (0.125-2 g l−1) and adsorption temperature (20°C-70°C). The equilibrium adsorption data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DRK) adsorption isotherm models. Of the four adsorption isotherms, the R2 value of Langmuir isotherm model for MB and CV were 0.969 and 0.926, respectively. Experimental data were analysed using the pseudo-first order, the pseudo-second order, intraparticle diffusion and Elovich models. The characteristic parameters for each model have been determined. In addition, the equilibrium thermodynamic parameters, including changes in Gibbs free energy, entropy and enthalpy are determined for the CV and MB on waste foundry sand.

Equilibrium and kinetic adsorption study of aqueous basic dye solutions using waste foundry sand

The aim of this study is to evaluate adsorption kinetics, isotherms and thermodynamic parameters of crystal violet (CV) and methylene blue (MB) dyes from aqueous solution using waste foundry sand. Adsorption studies were carried out at different initial dye concentrations (12.5-400 mg l−1), contact time (5-240 min), pH (3.0-9.0), sorbent doses (0.125-2 g l−1) and adsorption temperature (20°C-70°C). The equilibrium adsorption data were analysed by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DRK) adsorption isotherm models. Of the four adsorption isotherms, the R2 value of Langmuir isotherm model for MB and CV were 0.969 and 0.926, respectively. Experimental data were analysed using the pseudo-first order, the pseudo-second order, intraparticle diffusion and Elovich models. The characteristic parameters for each model have been determined. In addition, the equilibrium thermodynamic parameters, including changes in Gibbs free energy, entropy and enthalpy are determined for the CV and MB on waste foundry sand.

Adsorption behaviour of magnesium ferrite nanoparticles synthesized by co-precipitation and combustion methods

Adsorption of Cr (VI) from aqueous solution by magnesium ferrite (MgFe2O4) nanoparticles (NPs) synthesized by co-precipitation and combustion methods was studied using batch mode. The factors influencing adsorption viz. solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature were ascertained. Cr (VI) content was estimated spectrophotometrically. The maximum adsorption of Cr (VI) ions was achieved at pH 2.0. Thermodynamic parameters such as change in Gibb's free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were evaluated. NPs synthesized by different methods displayed small variation in the percent removal although BET surface area of NPs showed significant differences. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich adsorption isotherm models.

Remediation of water from crude oil spill using a fibrous sorbent

Abstract Remediation of oil-polluted water was studied using waste tire cord fiber WTCF as a waste fibrous sorbent. The rate of sorption, sorption capacity, oil retention, water uptake, adsorption isotherm model, and kinetic behavior were evaluated. It was found that the oil sorption capacity was equal to 15.45 g oil/g sorbent. For fixed amount of sorbent, oil sorption was increased with an increasing of the amount of oil until equilibrium state was reached. The sorbent was proven to have a high retention time; it can save 66.3% of the adsorbed oil after five minutes drainage. This property makes the material as a unique material to have such high retention time. The reusability of sorbents showed that this sorbent can have 75.7% of the sorption capacity after 10 cycles. The total amount of adsorbed oil was 107.66 g oil/g of WTCF for 10 cycles. Langmuir, Frendlich, Timken, ​Hurkins–Jura, Halsay, Radlich–Peterson, and ​Dubinin–Radushkevich adsorption isotherm models were applied to fit the adsorption remediation process. The remediation process using WTCH was following a second order rate kinetic and Radlich–Peterson adsorption isotherm model.

Experimental Investigation of Arsenic (III, V) Removal from Aqueous Solution Using Synthesized α-Fe2O3/MCM-41 Nanocomposite Adsorbent

Adsorption of arsenic (III, V) from aqueous solution onto the synthesized α-Fe2O3/MCM-41 nanocomposite adsorbent, as function of contact time, initial concentration of the solution, temperature, pH, and presence of other anionic species, has been investigated. Characterization of adsorbent was performed via XRD, FT-IR, TGA, TEM, and N2 adsorption–desorption techniques. The synthesized adsorbent belonged to the group of mesoporous materials with the mean pore diameter of 2.37 nm, specific surface area of 507.5 m2 g−1, and total pore volume of 0.571 cm3 g−1. The experimental data were analyzed by Langmuir, Freundlich, and Dubinin-Radushkevich (D–R) adsorption isotherms. Based on Langmuir isotherm, the maximum adsorption capacities at 298 K in the concentration range of 2–200 ppm were 133.3 and 102.1 mg g−1 for As(ш) and As(v), respectively. The adsorption experiments at different contact times indicated that the kinetics of adsorption accurately followed the pseudo-second-order rate equation. Thermodynamics parameters were calculated, and it was found that the adsorption process was spontaneous, exothermic, and favored at lower temperatures. The capability of regeneration and reusability of adsorbent was also examined in alkaline solutions.

Preparation and characterization of aspartic acid doped polypyrrole for the efficient removal of Cr(VI) from aqueous solution

A new aspartic acid doped polypyrrole (Asp-PPy) was prepared via in situ polymerization of pyrrole with aspartic acid for the removal of Cr(VI) from aqueous solutions. The prepared Asp-PPy was characterized using FT-IR, SEM with EDS, XRD, XPS and BET methods. The adsorption experiments were carried out in batch mode to optimize various parameters viz., contact time, pH, adsorbent dose, co-ions and temperature that influence the adsorption rate. Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models were applied to describe isotherm constants. Equilibrium data agreed well with the Langmuir isotherm model with maximum adsorption capacity of 176.7mg/g. Thermodynamic studies revealed that the nature of adsorption is spontaneous and endothermic. The kinetic process demonstrates that the adsorption process follows pseudo-second-order and intra-particle diffusion models. The mechanism of Cr(VI) adsorption by Asp-PPy was governed by the ionic interaction between NH3+ of Asp and HCrO4− ions. Asp-PPy can be reused successfully for the removal of Cr(VI) four times without loss of its removal efficiency. Asp-PPy can be a promising material to remove toxic Cr(VI) from the aqueous environment due to having high Cr(VI) capacity, good ion exchange property, non-toxic, environmental stability and low cost.

Treatment of hydrochloric acid using Mg–Al layered double hydroxide intercalated with carbonate

Mg–Al layered double hydroxide intercalated with CO32− (CO3·Mg–Al LDH) was found to take up only low amounts of Cl− during the treatment of hydrochloric acid. Low pH promotes the removal of Cl−. HCl is considered to react with CO32− in the interlayers of Mg–Al LDH as a result of which Cl− is probably intercalated in the interlayers. High pH of the Mg–Al LDH suspension leads to a lower extent of reaction between HCl and Mg–Al LDH, owing to the neutralization of the acid. We can state that the adsorption of Cl− on Mg–Al LDH is best described by the Dubinin–Radushkevich adsorption isotherm. The maximum adsorption amounts were calculated to be 1.4 and 0.6mmol/g for CO3·Mg–Al LDH with Mg/Al molar ratios of 2 and 4, respectively, whereas the adsorption energies were calculated to be 82 and 124kJ/mol, respectively. In summary, the removal of Cl− is caused by both the reaction between hydrochloric acid and CO32− in the interlayers of Mg–Al LDH as well as anion exchange between the HCO3− produced and a different Cl− ion in hydrochloric acid. This explains why the adsorption is best expressed by the D–R adsorption isotherm, which assumes a heterogeneous surface and non-constant adsorption potential.

Comparable Study of 4-chlorophenol Removal from Petrochemical Wastewater Using Mesoporous and Microporous Carbons: Equilibrium and Kinetics Investigations

In this study, an ordered mesoporous carbon structure with excellent adsorption properties towards chlorophenol compounds was synthesized using a hard template. The physico-chemical properties of the synthesized samples were studied using Small Angle X-ray Diffraction (SAXRD), Transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM) and nitrogen adsorption–desorption analysis. The capability of adsorption of 4-chlorophenol on mesoporous carbon has been investigated by varying the reaction time, initial concentration of 4-chlorophenol, adsorbents loading and the pH of the solution; and the results compared with commercial activated carbon as a microporous carbon. Freundlich, Langmuir, Tempkin and dubinin-radushkevich adsorption isotherms were used to model the equilibrium adsorption data for 4-chlorophenol compound. The kinetic analysis showed that the adsorption process was fitted with the pseudo-second-order kinetic model. The equilibrium data were investigated by the main adsorption isotherm models on the mesoporous and microporous carbons as adsorbents, which revealed that the Freundlich model was better to describe the 4-chlorophenol adsorption than other models. Also, the obtained results indicated that the adsorption capacity and equilibrium time for mesoporous carbon were better than microporous carbon, 90 mg/g after 25 minute compare to 60 mg/g after 60 minute, respectively.

Equilibrium, kinetic and thermodynamic studies of methyl orange removal by adsorption onto granular activated carbon

The adsorption of methyl orange (MO) onto granular-activated carbon (AC) is studied. The effects of initial dye concentration, AC dose, initial solution pH, stirring rate, and temperature on MO adsorption were investigated in a batch system. The experimental data were analyzed using the Langmuir, Freundlich, Elovich, Temkin, and Dubinin–Radushkevich adsorption isotherms, and the characteristic parameters and related correlation coefficients were determined for each isotherm at different temperatures. The best fit was achieved by the Langmuir isotherm equation, by increasing the maximum monolayer adsorption capacity from 20.7 to 46.1 mg/g, when the temperature increases from 283 to 313 K. Pseudo-first-order, pseudo-second-order, Elovich, Weber–Morris intraparticle diffusion and Boyd models were used to analyze the kinetic data obtained at different initial MO concentrations. The adsorption kinetic data were well described by the pseudo-second-order model, while the adsorption process was controlled by film diffusion. The Gibbs free energy, enthalpy, and entropy of the adsorption process were also evaluated, the results showing that the adsorption was spontaneous and endothermic under the examined conditions, and was presumably of a physical nature and non-reversible.

Adsorption of uranium(VI) and thorium(IV) by insolubilized humic acid from Ajloun soil – Jordan

Humic acid from Ajloun soil has been extracted and insolubilized. The insolubilized humic acid (NaIHA) was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermal gravimetric analysis, X-ray diffraction and differential scanning calorimetry. Adsorption of U(VI) and Th(IV) by NaIHA was studied using batch technique at different temperatures (25.0, 35.0 and 45.0 °C) and at different pH values (1.00, 2.00 and 3.00). It was found that NaIHA has higher uptake for Th(IV) than U(VI), and that the metal ion uptake by NaIHA increased with pH and reached a maximum at pH = 3. The kinetic studies were done, and showed that the equilibrium time for each metal ion occurs at 6 h to achieve maximum uptake level. Adsorption data were evaluated according to the Pseudo second-order reaction kinetic. The metal ions uptake properties by the NaIHA fit Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherms. Thermodynamic functions, ΔG°, ΔH° and ΔS° were determined for each metal ion. The positive values of ΔG° indicate that adsorption process is not highly favorable, while ΔH° values indicated that this process is endothermic. On the other hand, the process has positive entropy which means that the adsorption process increases the disorder of the system and it is entropy driven. Column experiments were used for the determination of metal ion loading capacity and desorption studies. The uptake capacities in column technique of U(VI) and Th(IV) ions are 2.63 and 4.85 mg metal ion/g NaIHA respectively. Recovery of U(VI) and Th(IV) ions was carried out by treatment of loaded insolubilized humic acid with 0.1 M and 1.0 M HNO3, the best recovery for U(VI) and Th(IV) ions were obtained when 1.0 M HNO3 was used.

Chlorella vulgaris biomass enriched by biosorption of polyphenols

Cell walls of microalgae are variable and contain non-specific domains where different molecules can bind. The enrichment of microalgal biomass with nutrients through adsorption can be an interesting process for the food and feed industry. In this study, naturally occurring polyphenols ((+)-catechin, (−)-epicatechin, quercetin, rutin and xanthohumol) were adsorbed onto nonliving cells of freshwater microalgae Chlorella vulgaris. The essential adsorption parameters such as biomass dose and contact time were examined and the adsorption was quantified with Langmuir, Sips and Dubinin–Radushkevich adsorption isotherms. The evaluation of isotherms proved the highest affinity towards Chlorella vulgaris biomass for xanthohumol and quercetin. The biosorption mechanism of Chlorella vulgaris biomass was well described by a pseudo second order kinetic model, with a high regression coefficient. The polyphenol-enriched microalgal biomass was also evaluated for its antioxidant activity. The highest antioxidant activity was detected in the case of biomass enriched with quercetin (77.5% of decolorized DPPH).

Removal of nickel(II) from aqueous solution using Citrus Limettioides peel and seed carbon

The agricultural wastes like Citrus Limettioides peel and seed to be suitable precursor for the preparation of carbon [Citrus Limettioides peel carbon (CLPC) and seed carbon (CLSC)] has been explored in the present work, utilizing sulfuric acid as the activating agent. Adsorption studies were performed by varying contact time, solution pH, adsorbent dose and temperature. The equilibrium time for Ni(II) ions was determined as 4h and optimal pH was 4–7. Surface morphology and functionality of the CLPC and CLSC were characterized by SEM, EDX and FT-IR. The experimental data were analysed using the Freundlich, Langmuir, Temkin, Redlich–Peterson, Sips and Dubinin–Radushkevich adsorption isotherm equations using nonlinear regression analysis. Equilibrium data were found to fit well in the Langmuir isotherm, which confirmed the monolayer coverage of Ni(II) ions. The Langmuir monolayer adsorption capacity of CLPC and CLSC was found to be 38.46 and 35.54mg/g. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic in nature. The kinetic data followed pseudo-second order model with film diffusion process. The adsorbents were tested with Ni(II) plating wastewater in connection with the reuse and selectivity of the adsorbents.

Application of a low-cost bagasse carbon-red mud (BCRM) adsorbent for adsorption of methylene blue cationic dye: adsorption performance, kinetics, isotherm, and thermodynamics

To understand adsorption property of bagasse carbon-red mud (BCRM), a low-cost adsorption material prepared from waste solid red mud and bagasse, for disposal of organic dyes in wastewater, the adsorption of methylene blue (MB) from aqueous solution on BCRM has been studied, and the adsorption treatment of real textile wastewater was also investigated. Characterization of BCRM was achieved by scanning electron microscope and nitrogen adsorption–desorption analysis. Effects of adsorption time, BCRM dosage, initial concentration, temperature, and initial pH on the adsorption of MB were explored. From the characterization of adsorbent, it can be seen that the prepared BCRM was a porous material composed of particles with rough surface and loose structure, and an excellent mesoporous material with high specific surface area and good mesopore structure. The adsorption results showed that the data fitted better with pseudo-second-order kinetic model (R2 = 0.9995) than pseudo-second-order kinetic and intraparticle diffusion models. Langmuir model was better fit isotherm for MB adsorption on BCRM than Freundlich and Dubinin–Radushkevich adsorption isotherms. It can be drawn that MB adsorption on BCRM was a monolayer adsorption and the adsorption occurred at specific homogeneous sites on the adsorbent. The results of adsorption thermodynamics indicated MB adsorption on BCRM was a spontaneous, endothermic, and physical process. The adsorption treatment of real textile wastewater by BCRM implied BCRM was an effective and regenerable adsorbent for removal of dye from wastewater.