Methylene Blue Adsorption Process Research Articles

Preparation and adsorption property of graphene oxide by using waste graphite from diamond synthesis industry

Graphene oxides (GO) were prepared from waste graphite from diamond synthesis industry by using the modified Hummers method. The phase composition, microstructure, specific surface area and pore size distribution of the waste graphite and the as-prepared GO samples were characterized by X-ray diffraction, Fourier transformed infrared spectra, Ultraviolet visible spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy and nitrogen adsorption-desorption tests. The adsorption property of GO to methylene blue (MB) was investigated. The results show that the as-prepared GO has few layers, specific surface area of 116.6 m2 g−1 and a little different structure from those prepared by using natural flake graphite. It exhibited excellent adsorption performance in MB aqueous solution. Adsorption time, GO dosage, initial concentration, and pH value of MB aqueous solution play important roles but the solution temperature had a little effect on the removal rate of MB and the adsorption capacity of GO. Under the condition of a GO dosage of 5.7 mg, room temperature, initial concentration of 12 mg L−1, pH value of 6.5 and adsorption for 40 min, the removal rate of MB and the adsorption capacity of GO reached 96.05% and 379.89 mg g−1, respectively. The adsorption process of MB onto GO met well with a pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The adsorption reaction was spontaneous and purely based on endothermic process.

Facile preparation of functionalized carbon nanotubes with tannins through mussel-inspired chemistry and their application in removal of methylene blue

Since their first discovery, the carbon nanotubes (CNTs) have attracted great research attention owing to their great mechanical properties, high chemical stability, unique electronic properties and diameter ratio. The CNTs have been extensively applied as adsorbents to remove various environmental pollutants for their large surface areas. Nevertheless, the performance of pristine CNTs for removal of cationic dye methylene blue (MB) is largely limited for their poor dispersibility and lack of functional groups. In this work, the functionalized CNTs have been synthetized through the self-polymerization of tannins under alkaline solution. The obtained samples, including pristine CNTs and CNT-TA composites, were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The effects of adsorption factors, including contact time, initial MB concentration, solution pH and temperature, were scientifically investigated. Results indicate that the adsorption capacity of functionalized CNTs at room temperature could reach up to 105 mg/g, which is much higher than that of pristine CNTs in the same experimental condition. According to the results of adsorption kinetics, isotherms and thermodynamics, the adsorption of MB onto CNT-TA follows the pseudo-first-order model and Freundlich isotherm model, and the MB adsorption process is exothermic and spontaneous. These results indicate the functionalized CNTs could be applied as high-performance adsorbents with great potential of adsorbing the cationic dye pollutants from aqueous solution.

SrFe2O4 nanoferrites and SrFe2O4/ground eggshell nanocomposites: Fast and efficient adsorbents for dyes removal

In recent years nanomaterials are attracting much attention in water pollution treatment due to their greater surface area and unique properties. In this work, a micro emulsion method had been successfully utilized to synthesize novel strontium nanoferrites, SrFe2O4 (SF) as an efficient adsorbent for both anionic dye erichrome black T (EBT) and cationic dye methylene blue (MB). To further improve the efficiency of SF, eggshells powder (EgP) was employed as a support or co sorbent to produce another adsorbent named SF@EgP by combining EgP and SF using solvothermal method. The adsorbents were characterized by XRD, SEM techniques and further impendence spectroscopy and electrochemical characterization was also performed for SF. The SF and SF@EgP were tuned for EBT and MB removal and proved to be novel and efficient adsorbents and their adsorption efficiency was also compared with EgP. Using these model dyes, we investigated the influence of pH, adsorbent quantity, time and initial dyes concentrations on adsorption. The adsorption process of EBT and MB was examined by kinetics, isothermal and thermodynamics modeling that respectively directed that the removal of dyes was much quicker with SF@EgP compared to EgP following pseudo second order, that it followed Langmuir isotherm because of higher R2 and closeness between experimental/theoretical adsorption capacities and that the adsorption was spontaneous and endothermic. In addition, the SF and SF@EgP were regenerated and recycled successfully showing their reusability. In short these novel adsorbents not only tunable and showed reusability for cationic and anionic dyes with fast adsorption but also provide valuable clues towards synthesis and adsorption studies of other nanomaterials.

Isotherm Studies of Adsorption of Methylene Blue by Palm Kernel Shell

The main aim of this work is determine the feasibility of palm kernel shell (PKS) with phosphoric acid impregnation to biosorb methylene blue (MB) from aqueous solution by carrying out isotherm studies of the process. The influence of various factors such as contact time, initial dye concentration, adsorbent dosage, pH of dye solution and temperature were investigated in a batch adsorption technique. Result showed that adsorption of methylene blue (MB) dye was favourable at acidic pH. The percentage adsorption was found to increase with time of agitation, temperature, and mass of adsorbent but decreased with increase in initial MB concentration. In order to obtain a suitable model for the MB adsorption process, obtained data were fitted into different isotherm models like Langmuir and Freundlich models. Results showed that Freundlich adsorption isotherm model best describe MB adsorption onto palm kernel shell (PKS).

Polyvinyl alcohol/Fe3O4@carbon nanotubes nanocomposite: Electrochemical-assisted synthesis, physicochemical characterization, optical properties, cytotoxicity effects and ultrasound-assisted treatment of aqueous based organic compound

In this research study, the polyvinyl alcohol/Fe3O4@carbon nanotubes (PVA/Fe3O4@CNTs) nanocomposite was prepared by electrochemical-assisted synthesis method, characterized by FT-IR, UV–vis, FE-SEM, TEM, BET and XRD techniques, and subsequently applied for the ultrasound-assisted removal of methylene blue (MB) dye from aqueous solution and as antibacterial agent in vitro investigation against Proteus mirabilis (PM), Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (E. Coli) and Pseudomonas aeruginosa (PAO1) bacteria. The effects of important variables such as the initial concentration of MB, adsorbent mass, sonication time and pH on the removal percentage of MB were investigated and optimized by central composite design (CCD). The experimental results were applied for the construction of a quadratic model to predict the response following the analysis of variance (ANOVA) and to obtain useful information about the possible interaction between the variables and their main effects. The high F-value (207.38), low P-value (<0.0001) and non-significant lack of fit (P-value> 0.05) along with the reasonable value of the coefficient of determination (R2=0.99452) confirmed a good correlation between the experimental and predicted values. The highest removal percentage of 99.5% was attained at the optimum conditions of 0.035g of the adsorbent, 25.0mg L−1 of dye concentration, 6 min sonication time and pH=5.5. The adsorption process of MB by PVA/3wt% Fe3O4@CNTs was well described by pseudo-second-order kinetic and Langmuir isotherm models. A low dose of PVA/Fe3O4@CNTs nanocomposite (0.005g) was successfully used for the adsorption of MB (R%>90.0%) within a short time (6.0min) with the highest monolayer adsorption capacity of 250.10mgg−1 at 25°C.

Enhanced removal performance for methylene blue by kaolin with graphene oxide modification

Abstract In this study, graphene oxide modified kaolin (GO-kaolin) composites (named 2% GK, 5% GK, and 10% GK) were synthesized by a facile method. Characterization results indicated the successful modification of GO on kaolin surface. To understand the dye removal performance of kaolin with GO modification, batch adsorption experiments were carried out using methylene blue (MB) as a model dye pollutant in various experimental conditions The adsorption results showed that the increase of GO content in modified kaolin composite could effectively enhance the removal of MB from aqueous solution in each experiment condition, which was attributed to the increase of special surface area and active adsorption sites. Kinetic analysis of MB adsorption by GO-kaolin samples was shown a better fitting to pseudo-second-order kinetic models. The adsorption isotherm data were better fitted to Langmuir isotherm models. The values of thermodynamics constants suggested that the adsorption reaction was endothermic in nature. Furthermore, adsorption process of MB on kaolin was changed after the introduction of GO. An excellent regeneration performance of 10% GK was observed via the regeneration experiment. The results show that kaolin modified with suitable GO content is a high-efficiency and reusable adsorbent in the removal of MB from wastewater.

Carbon-doped graphitic carbon nitride as environment-benign adsorbent for methylene blue adsorption: Kinetics, isotherm and thermodynamics study

Abstract A novel, carbon-doped graphitic carbon nitride (C C3N4-20) was used for methylene blue (MB) removal from an aqueous solution. In dye adsorption experiments, C C3N4-20 showed a high MB adsorption efficiency due to its extended π-conjugation system and porous structure, the maximum adsorption capacity of C C3N4-20 for MB was 57.87 mg g−1, when the initial concentrations of MB were 20 mg L−1. A Langmuir model fit the MB adsorption isotherm of C C3N4-20, and a pseudo-second-order kinetic model fit the adsorption kinetics. The MB adsorption process on C C3N4-20 is physical and mainly via electrostatic attraction and π–π interactions.

Potential of Cellulose Functionalized with Carboxylic Acid as Biosorbent for the Removal of Cationic Dyes in Aqueous Solution.

In the last decade, adsorption has been used to minimize the pollution caused by dyes, which represents a serious environmental problem. In this context, this work reports the preparation of phthalic anhydride-modified cellulose (PhCel), through the reaction of cellulose (Cel) with phthalic anhydride (Ph). The efficiency of the reaction was observed by elemental analysis, Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermogravimetry/derivative thermogravimetry (TG/DTG). The adsorbent matrix (Cel and PhCel) was used in the removal of crystal violet (CV) and methylene blue (MB) dyes in aqueous medium. In the kinetic study, the experimental data obtained had the best fit to the pseudo-first-order model. In general, the isotherms obtained at different temperatures had a best fit to the model proposed by Langmuir, and the CV and MB adsorption process in adsorbent matrixes can be favored strictly by hydrogen bonds and/or electrostatic interactions for Cel and electrostatic interactions for PhCel.

Growth and optimization of carbon nanotubes in powder activated carbon for an efficient removal of methylene blue from aqueous solution

ABSTRACTThis work demonstrated the synthesis of carbon nanotubes (CNTs) on powder activated carbon (PAC) impregnated with Ni-catalyst through chemical vapour deposition. The optimized effects of reaction temperature, time and feedstock flow rates on CNT growth were examined. Potassium permanganate (KMnO4) and potassium permanganate in acidic solution (KMnO4/H2SO4) were used to functionalize CNTs samples. A primary screening of methylene blue (MB) adsorption was conducted. The chemical, physical and morphological properties of the adsorbent with the highest removal efficiency were investigated using FESEM, EDX, TEM, BET surface area, RAMAN, TGA, FTIR, and zeta potential. The resulting carbon nanotube-loaded activated carbons possessed abundant pore structure and large surface area. The MB removal by the as-synthesized CNTs was more remarkable than that by the modified samples. Adsorption studies were carried out to evaluate the optimum conditions, kinetics and isotherms for MB adsorption process. The response surface methodology-central composite design (RSM-CCD) was used to optimize the adsorption process parameters, including pH, adsorbent dosage and contact time. The investigation of the adsorption behaviour demonstrated that the adsorption was well fitted with the pseudo-second-order model and Langmuir isotherm with the maximum monolayer adsorption capacity of 174.5 mg/g. Meanwhile, the adsorption of MB onto adsorbent was driven by the electrostatic attraction and π-π interaction. Moreover, the as-obtained CNT-PAC exhibited good reusability after four repeated operations. In view of these empirical findings, the low-cost CNT-PAC has potential for removal of MB from aqueous solution.

MoS2‐TiO2 Nanocomposite with Excellent Adsorption Performance and High Antibacterial Activity

AbstractThe need of multifunctional advanced materials, facilitating clean and sustainable environment is the key issue from the perspective of materials scientists. This study demonstrates facile and scalable synthesis of MoS2‐TiO2 nanocomposites and their excellent performance as nanoadsorbents and antibacterial agent. The synthesized composites, with different loading of MoS2 and TiO2, were examined by XRD, XPS, RAMAN, FESEM and HRTEM for structural, chemical and morphological details. The MoS2‐TiO2 nanocomposite displays adsorption capacity as high as 364.56 mg g−1 for methylene blue (MB) at room temperature and the kinetic data reveal that the adsorption process of MB is well‐matched with the pseudo‐first‐order model. The MoS2‐TiO2 nanocomposites, with different morphology, have shown their capability as an organic dye scavenger with high speed and efficiency. Moreover the composites execute considerable antibacterial activity against Gram positive Staphylococcus aureus and Gram negative Escherichia coli bacteria. Thus the presented MoS2‐TiO2nanocomposite, with synergistic performance, shows huge potential in the search of multifunctional smart materials for future technology to address environment issues.

Encapsulating TiO2 into Polyvinyl Alcohol Coated Polyacrylonitrile Composite Beads for the Effective Removal of Methylene Blue

In this work, novel nanocomposite beads based on polyvinyl alcohol (PVA) coated polyacrylonitrile (PAN) with encapsulation of TiO2 nanoparticles (PPT) were developed successfully via a novel green synthetic method and its methylene blue (MB) removal ability by adsorption was also investigated. As-prepared nanocomposite beads were characterized by different techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). TiO2 nanoparticles were encapsulated into the composite beads to endow the composite beads with photocatalytic ability and enhance its adsorption capacity for MB. Batch experiments with several variables such as TiO2 nanoparticle content, pH of the solution, contact time and initial MB concentration were carried out. The adsorption kinetic study revealed that the MB adsorption process agreed well with pseudo-second order model and showed 3-stage intraparticle diffusion model. The adsorption isotherm study indicated that the MB adsorption process could also be better described by Langmuir isotherm model. According to Langmuir isotherm equation, the maximum adsorption capacity and removal rate for MB was 242.13 mg g-1 and 98.4%, respectively. Moreover, the stability and reusability of as-prepared PPT beads were further explored and results demonstrated that PPT could be reused at least five times with negligible loss of sorption capacity and removal rate. Therefore, PPT is expected to be a potential candidate for effluents treatment.

Synthesis of zeolite L using rice husk ash silica for adsorption of methylene blue: kinetic and adsorption isotherm

Rice husk has a high silica content, so it can be utilized as silica source for zeolite synthesis. In this research, synthesis of zeolite L has been done using silica from rice husk ash without organic template. The synthesized zeolite L is then used as an adsorbent to adsorb methylene blue dye. The steps of zeolite L synthesis include: silica extraction from rice husk ash using NaOH and zeolite L synthesis using hydrothermal method with molar ratio 10 SiO2: Al2O3: 4 K2O: 100 H2O at 170°C for 24 hours. The resulting Zeolite L was then characterized by XRD and SEM. The absorption capacity of methylene blue solution by zeolite L was observed experimentally through the effect of pH of the solution, contact time, and initial concentration of the solution, then determining the isotherm and its absorption kinetics. From XRD and SEM results of zeolite L sample, it is shown that zeolite L has been formed and its particle morphology is a hollow cylinder with cylinder diameter of 0.049 - 0.123 μm. The adsorption process refers to the Freundlich isotherm model which provides the highest correlation coefficient. The methylene blue adsorption process by zeolite L follows pseudo second-order kinetics.

Net-like porous activated carbon materials from shrimp shell by solution-processed carbonization and H3PO4 activation for methylene blue adsorption

In this work, shrimp shell waste was used as a novel precursor for the production of a net-like porous activated carbon by solution-processed carbonization and chemical activation with phosphoric acid (H3PO4). The H3PO4 activation of activated carbon from shrimp shell (PS-Ac) was characterized in terms of textural, surface and morphological properties by N2 sorption, Raman, HR-TEM and SEM-EDS analyses. It showed that PS-Ac was a net-like porous material with mesoporous structures. The average pore size and BET surface area were 4.5nm and 560.6m2g−1, respectively. The obtained PS-Ac was then employed for the adsorption of methylene blue (MB) dyes and systematically investigated the effect of solution pH, initial concentration, contact time and temperature for MB adsorption. Experimental data were well described by the Langmuir isotherm and the pseudo-second order model with the maximum adsorption capacity of 826mgg−1(MB), which showed to be high compared to other ACs reported in the literature. Thermodynamic parameters indicated that PS-Ac for MB adsorption process was spontaneous and endothermic. Moreover, coupled with experimental results, FT-IR and XPS analysis suggested that the adsorption mechanism of MB onto PS-Ac was possible attributed to electrostatic interaction between the surface of functional groups (PO43−, COO−, O) on adsorbent and the cation ions MB-N+ in the basic solution.

Removal of crystal violet and methylene blue from aqueous solutions using the fly ash-based adsorbent material-supported zero-valent iron

A novel granular adsorbent material containing zero-valent iron (ZVI-GAM) was prepared with fly ash as skeletal material, bentonite as binder and Enteromorpha prolifera as pore former. ZVI was synthesized by direct reduction of iron ore tailings powder with the coke as reductant in high temperature reducing atmosphere and embedded in the fly ash-based porous adsorbent, which could reduce the agglomeration and oxidation of ZVI. The structure of ZVI-GAM was characterized by SEM, EDX, XRD, FTIR and BET. The removal amount of crystal violet (CV) and methylene blue (MB) was evaluated at different contact time, initial dye concentration, pH values and temperature. The adsorption isotherms of CV and MB fitted well to the Langmuir model. The maximum removal capacity of ZVI-GAM for CV and MB was found to be 172.41mg/g and 151.52mg/g, respectively. The adsorption processes of CV and MB could be described by a pseudo-second-order kinetic model. The reduction kinetics of CV by ZVI-GAM fitted to pseudo-first-order kinetics model. The results indicated that chemisorption and reduction controlled the removal process of CV while chemisorption only controlled the removal process of MB. The thermodynamic study indicated that the adsorption processes of CV and MB were found to be endothermic and spontaneous. Therefore, ZVI-GAM was an effective, low-cost and recyclable material for dye removal.

Methylene blue removal from aqueous solution by magnetic clinoptilolite/chitosan/EDTA nanocomposite

In this study, clinoptilolite as a natural zeolite which was magnetized using precipitation of maghemite nanoparticles was coated by chitosan and then modified by thylenediamine tetra-acetic acid to add functional groups and its performance in the removal of toxic methylene blue from aqueous solution was investigated. Synthesized magnetic nanocomposite was characterized by VSM, XRD, SEM, and FTIR analyses. The saturation magnetization of the final nanocomposite was obtained as 22.2 emu/g. In addition, the factors affecting adsorption process and its optimization were investigated using response surface methodology and central composite design. Data obtained by different isotherm, adsorption kinetic and thermodynamic models were also studied. The results showed good agreement of these data with the Freundlich isotherm model (R 2 = 0.99), and it was found that adsorption follows the second-order kinetics model (R 2 = 1). Negative values of ΔG and positive values of ΔH obtained from this adsorption thermodynamic study revealed that the methylene blue adsorption process is exothermic and spontaneous. The optimum conditions to ensure maximum adsorption efficiency were determined, and included pH = 5.54, adsorbent amount of 0.03 g, temperature of 31.18 °C, and initial solution concentration of 16.21 mg/l which resulted in a removal efficiency of 99.44%. The results indicated that this nanocomposite can be used as a proper adsorbent for adsorbing methylene blue and other dye contaminants.

Preparation and characterization of distillers’ grain based activated carbon as low cost methylene blue adsorbent: Mass transfer and equilibrium modeling

In this study, an orthogonal array design method was employed to optimize carbon preparation from distillers’ grain (DGAC). The physical and chemical properties of the produced DGAC were characterized using scanning electron microscopy (SEM), N2 adsorption–desorption technique (Brunauer-Emmett-Teller, BET), and fourier transform infrared spectroscopy (FTIR). The BET surface area of DGAC was found to be 1430 m2/g, with average pore diameter of 2.19 nm. Batch experiments were carried out to study the adsorption of methylene blue (MB) onto DGAC. External mass transfer model, internal diffusion model, Boyd model and pseudo-second-order model were used to fit the adsorption kinetic process of MB adsorption onto DGAC. The results shows the external mass transfer model could only describe the adsorption for the initial 5 min, and later the internal diffusion in the pores of the carbon particles became a main resistance, chemisorption was also involved in the adsorption process. The adsorption equilibrium was described best by Langmuir isotherm with maximum adsorption capacity of 934.6 mg/g of MB at 55°C, thermodynamic studies confirmed that the adsorption of MB onto DGAC was spontaneous and thermodynamically favourable. These findings support the potential of using distillers’ grain as raw material to prepare well-developed porous texture adsorbent with huge MB removal capacity.

Cr(OH)3-NPs-CNC hybrid nanocomposite: a sorbent for adsorptive removal of methylene blue and malachite green from solutions.

In this article, Cr(OH)3 nanoparticle-modified cellulose nanocrystal (CNC) as a novel hybrid nanocomposite (Cr(OH)3-NPs-CNC) was prepared by a simple procedure and used as a sorbent for adsorptive removal of methylene blue (MB) and malachite green (MG) from aqueous solution. Different kinetic models were tested, and the pseudo-second-order kinetic model was found more suitable for the MB and MG adsorption processes. The BET and Langmuir models were more suitable for the adsorption processes of MB and MG. Thermodynamic studies suggested that the adsorption of MB and MG onto Cr(OH)3-NPs-CNC nanocomposite was a spontaneous and endothermic process. The maximum adsorption capacities for MB and MG were reached 106 and 104mg/g, respectively, which were almost two times higher than unmodified CNC. The chemical stability and leaching tests of the Cr(OH)3-NPs-CNC hybrid nanocomposite showed that only small amounts of chromium were leached into the solution.

Facile preparation of water-soluble hyperbranched polyamine functionalized multiwalled carbon nanotubes for high-efficiency organic dye removal from aqueous solution

Water-soluble hyperbranched polyamine functionalized multiwalled carbon nanotubes nanocomposite (WHPA-OMCNT) was successfully prepared and applied to water remediation in this paper. WHPA-OMCNT was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), zeta potential, scanning electron microscopy (SEM) and transmission electron microscope (TEM) analyses. WHPA-OMCNT exhibited excellent adsorption performance for removal of organic dyes e.g., methylene blue (MB), malachite green (MG) and methyl violet (MV). The equilibrium adsorption capacity was 800.0 mg g−1 for MB, 840.3 mg g−1 for MG and 970.9 mg g−1 for MV under the optimal conditions. The pseudo-second order equation and the Langmuir model exhibited good correlation with the adsorption kinetic and isotherm data for all three pollutants, respectively. The thermodynamic results (ΔG < 0, ΔH < 0, ΔS < 0) implied that the adsorption process of MB, MG and MV was feasible, exothermic and spontaneous in nature. A possible adsorption mechanism has been proposed, where H-bonding, electrostatic attraction and π-π stacking interactions dominated the adsorption of the organic dyes. In addition, the excellent reproducibility endowed WHPA-OMCNT with the potential for application in water treatment.

Characterization of mesoporous magnesium silicate with hierarchical structure and its adsorption performance for dye and lead ion

Mesoporous magnesium silicate was prepared at 100°C by hydrothermal method with the assisted template of mesoporous silica SBA-15 filled with carbon. The samples showed hierarchical structure composed of nanopetals and mesopores, specific surface area of 283m2/g, as well as bimodal pore size distributions with the mean pore size of 3.5 and 5.0nm. The obtained mesoporous magnesium silicate was utilized as an adsorbent for the removal of methylene blue and lead ions. The fast adsorption process of methylene blue was correlated well with the pseudo-second-order kinetics. The Langmuir isothermal model fitted the adsorption data of methylene blue and lead ion. The adsorption capacities for methylene blue and lead ion were determined to be 341 and 417mg/g, respectively. In addition, after adsorption of methylene blue, hierarchical magnesium silicate with mesoporous structure was regenerated by calcination and still showed the adsorption capacity of 203mg/g, which indicated its efficient reusability. This work presented an available route for the application of magnesium silicate as a promising adsorbent.

Oxygen functionalized carbon nanocomposite derived from natural illite as adsorbent for removal of cationic and anionic dyes

Oxygen functionalized carbon nanocompositse (O-I@C) based on glucose and illite were obtained through mild hydrothermal process and surface oxidation. The surface properties of the prepared O-I@C were analyzed by Boehm titration, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Specific surface area (BET). The results showed that the surfaces of the prepared O-I@C nanocomposites were functionalized with abundant oxygen-containing functional groups (OFGs). The functionalized O-I@C nanocomposites were proven to be effective adsorbents for fast removal of congo red (CR) and methylene blue (MB) from aqueous solution within 10min. It is demonstrated that the initial pH of dyes solution has an important influence on the adsorption process of both CR and MB, indicating that the OFGs created on the surfaces of the materials are responsible for the promoted adsorption ability. Furthermore, it is also proved that the adsorption isotherms of CR and MB obey the Langmuir model, with the maximum adsorption capacities of 238.40mg/g and 215.28mg/g, respectively. In addition, the used materials could be regenerated by washing with NaOH solution and reused at least four times, which exhibits potential applications as efficient and easily reusable adsorbents for the rapid removal of anionic dye CR and cationic dye MB from wastewater.