Investigation of α‐iron oxide‐coated polymeric nanocomposites capacity for efficient heavy metal removal from aqueous solution

In the present study, PS@α‐Fe₂O₃ nanocomposites were prepared by chemical microemulsion polymerization approach and the ability of magnetic beads to remove Cu(II) ions from aqueous solutions in a batch media was investigated. Various physico‐chemical parameters such as pH, initial metal ion concentration, temperature, and equilibrium contact time were also studied. Adsorption mechanism of Cu²⁺ ions onto magnetic polymeric adsorbents has been investigated using Langmuir, Freundlich, Sips and Redlich–Petersen isotherms. The results demonstrated that the PS@α‐Fe₂O₃ nanocomposite is an effective adsorbent for Cu²⁺ ions removal. The Sips adsorption isotherm model (R² > 0.99) was more in consistence with the adsorption isotherm data of Cu(II) ions compared to other models and the maximum adsorbed amount of copper was 34.25 mg/g. The adsorption kinetics well fitted to a pseudo second‐order kinetic model. The thermodynamic parameters (ΔH°, ΔS°, and ΔG°) were calculated from the temperature dependent sorption isotherms, and the results suggested that copper adsorption was a spontaneous and exothermic process. POLYM. ENG. SCI., 55:2735–2742, 2015. © 2015 Society of Plastics Engineers     

Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

Fe₃O₄/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe₃O₄/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.     

Removal of Cu2+ and Pb2+ ions from aqueous solutions by starch-graft-acrylic acid/montmorillonite superabsorbent nanocomposite hydrogels

In this study, the removal of copper(II) and lead(II) ions from aqueous solutions by Starch-graft-acrylic acid/montmorillonite (S-g-AA/MMT) nanocomposite hydrogels was investigated. For this purpose, various factors affecting the removal of heavy metal ions, such as treatment time with the solution, initial pH of the solution, initial metal ion concentration, and MMT content were investigated. The metal ion removal capacities of copolymers increased with increasing pH, and pH 4 was found to be the optimal pH value for maximum metal removal capacity. Adsorption data of the nanocomposite hydrogels were modeled by the pseudo-second-order kinetic equation in order to investigate heavy metal ions adsorption mechanism. The observed affinity order in competitive removal of heavy metals was found Cu²⁺ > Pb²⁺. The Freundlich equations were used to fit the equilibrium isotherms. The Freundlich adsorption law was applicable to be adsorption of metal ions onto nanocomposite hydrogel.     

Removal of heavy metals by polysaccharide: a review

ABSTRACT

Industries produce large amounts of heavy metal waste that are hazardous to the environment. Thus, heavy metal ions such as nickel (II), lead (II), copper (II), cadmium (II), and zinc (II), must be removed from wastewater. One commonly employed method is biosorption, which is the adsorption of metal ions by biomaterials such as polysaccharides. In this review, polysaccharides are classified into four groups: polysaccharide homopolymers, polysaccharide blends, copolymers, and polysaccharide composites. Pristine natural polysaccharides like chitin, chitosan, cellulose, starch, and alginate which have multiple functional groups. Additional functionalization is introduced in the form of blending, grafting, or mixing with various nanomaterials having additional functional group to make it more efficient for heavy metal ion adsorption. Introduction of second component onto the main polymer chain not only introduce functionality but enhance mechanical strength which is one of the vital requirements for the recyclability of adsorbent. Longer the time adsorbent is reused more economical is the removal process of metal ions from wastewater. Heavy metal ions undergo various types of interaction like π-π interactions, dipole–dipole interaction, hydrogen bonding or van der walls force with homopolymer, copolymers, blends, or nanocomposite having anions or electron-rich group. Adsorption process is studied by adsorption kinetics and adsorption isotherms. This review represents the adsorption behavior of chitosan, cellulose, starch, alginate, and their derivatives.     

Adsorption of Pb2+ and Cd2+ onto a Novel Activated Carbon‐Chitosan Complex

A novel activated carbon‐chitosan complex adsorbent (ACCA) was prepared via the crosslinking of glutaraldehyde and activated carbon‐(NH₂‐protected) chitosan complex under microwave irradiation. The surface morphology of this adsorbent was characterized. The adsorption of ACCA for Pb²⁺ and Cd²⁺ was investigated. The results demonstrate that ACCA has higher adsorption capacity than chitosan. The adsorption follows pseudo first‐order kinetics. The isotherm adsorption equilibria are better described by Freundlich and Dubinin‐Radushkevich isotherms than by the Langmuir isotherm. The adsorbent can be recycled. These results have important implications for the design of low‐cost and effective adsorbents in the removal of heavy metal ions from wastewaters.     

Synthesis of Fe2O3-coated and HCl-treated bauxite ore waste for the adsorption of arsenic (III) from aqueous solution: Isotherm and kinetic models

The present work has focused on the removal of arsenic (III) using two effective adsorbents such as red mud treated with HCl and coated with Fe₂O₃. Adsorption of As (III) was performed by the function of pH, adsorbent dose, contact time, initial ion concentration, and the appropriate conditions for adsorption were determined. The characterization studies of the adsorbent were analyzed using X-ray diffraction, X-ray fluorescence, Brauner–Emmett–Teller, scanning electron microscope, and FTIR spectroscopy. The result of the studies shows that the adsorbent is suitable for the effective removal of As (III) ions. Batch adsorption process showed that the maximum adsorption occurred at Fe₂O₃-coated red mud. The equilibrium data were well fitted to the nonlinear Langmuir isotherm model and the maximum adsorption capacity (q_m) of Fe₂O₃-coated red mud was found to be 21.85?mg?g^?1 which indicates that Fe₂O₃-coated red mud had more adsorption capacity. In the Freundlich isotherm, the experimentally obtained n value of Fe₂O₃-coated red mud was 2.393 which indicates the favorable adsorption of As (III) on the adsorbent. Dubinin–Radushkevich isotherm confirms that the adsorption process is physical in nature. Furthermore, the adsorption kinetic studies followed the pseudo-first-order model. All the results concluded that Fe₂O₃-coated red mud can be considered as a cost-effective and potential adsorbent for As (III) removal.     

REMOVAL OF Cd2+, Cu2+, AND Ni2+ METALS FROM SIMULATED WASTEWATER IN SINGLE AND COMPETITIVE SYSTEMS USING LOCAL IRAQI PHOSPHATE ROCKS

The equilibrium uptake of cadmium (Cd²⁺), copper (Cu²⁺), and nickel (Ni²⁺) ions, both singly and in combination, by local Iraqi phosphate rocks (PR) was studied in a batch system. The phosphate rock was characterized using BET, FT-IR, XRD, and SEM techniques. Adsorption isotherms were developed for both the single and ternary-component systems and expressed by the mono- and multicomponent Langmuir, Freundlich, Redlich-Peterson, and Dubinin-Radushkevich adsorption models; model parameters were estimated by the nonlinear regression method using STATISTICA version 6 software. To understand the action of metals uptake, factors influencing the adsorption of the heavy metals including pH, initial metal ion concentration, weight of the adsorbent, mixing speed, contact time, and temperature were investigated. It was found that the mono- and multicomponent adsorption equilibrium data fitted very well to the Langmuir model with high determination coefficient (R ²). The maximum loading capacities (q _max) were 70.852, 53.372, and 48.045 mg/g for Cd²⁺, Cu²⁺, and Ni²⁺ respectively. However, in the ternary system the loading capacity decreased because of competition between ions to binding sites of the adsorbent. Adsorption data were modeled using the pseudo-first- and pseudo-second-order kinetic and intraparticle diffusion models. It was seen that the pseudo- first-order kinetic equation could best describe the adsorption kinetics. Thermodynamic parameters showed that the adsorption of investigated heavy metals onto PR was endothermic and spontaneous in nature and the process is physiosorption. Fourier transform-infrared spectroscopy (FT-IR) analysis indicated that carboxylic (C?O), phosphine (p-H), and hydroxyl (–OH) groups in PR played an important role in the adsorption process. In conclusion, PR was found suitable as an abundant adsorbent for removal of the selected metal ions from aqueous solutions.     

Facile preparation of magnetic chitosan modified with thiosemicarbazide for adsorption of copper ions from aqueous solution

In this study, magnetic chitosan modified with thiosemicarbazide (TSC‐Fe₃O₄/CTS) was facilely synthesized with glutaraldehyde as the crosslinker, and its application for removal of Cu(II) ions was investigated. The as‐prepared TSC‐Fe₃O₄/CTS was characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray powder diffraction (XRD), and scanning electron microscopy (SEM). The results showed that TSC‐Fe₃O₄/CTS has high adsorption capacity and selectivity towards Cu(II) ions. Adsorption experiments were carried out with different parameters such as pH, solution temperature, contact time and initial concentration of Cu(II) ions. The adsorption process was better described by the pseudo‐second‐order model. The sorption equilibrium data was fitted well with the Langmuir isotherm model and the maximum adsorption capacity toward Cu(II) ions was 256.62 mg/g. The thermodynamic parameters indicated that the adsorption process of Cu(II) ions was exothermic spontaneous reaction. Moreover, this adsorbent showed excellent reusability and the adsorption property remained stable after five cycles. This adsorbent is believed to be one of the promising and favorable adsorbent for the removal of Cu(II) ions from aqueous solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44528.     

Preparation of aminoalkyl celluloses and their adsorption and desorption of heavy metal ions

Aminoalkyl celluloses (AmACs) were prepared from 6-chlorodeoxycellulose and aliphatic diamines H₂N(CH₂)_mNH₂ (m = 2, 4, 6, 8). Their adsorption and desorption of divalent heavy metal ions such as Cu²⁺, Mn²⁺, Co²⁺, Ni²⁺ and their mixtures were also investigated in detail. Adsorption of metal ions on AmACs was remarkably affected by the pH of the solution, the metal ion and its initial concentration, and also the number of methylene units in the diamines. No adsorption of metal ions occurred on AmACs in strongly acidic solutions. However, metal ions were adsorbed rapidly on AmACs from weakly acidic solutions and the amount of adsorption increased with increasing pH. The effectiveness of AmACs as adsorbents decreased with increasing length of the methylene moiety, and AmACs from ethylenediamine (m = 2) was most effective. The adsorption of metal ions on AmACs was in the order Cu²⁺ > Ni²⁺ > Co²⁺ > Mn²⁺. Accordingly, their behavior followed the Irving-Williams series and Cu²⁺ ions were preferentially adsorbed from solutions containing metal ion mixtures. The adsorbed ions were easily desorbed from the AmACs by stirring in 0.1 M HCl.     

Continuous preparation of Fe3O4 nanoparticles combined with surface modification by L-cysteine and their application in heavy metal adsorption

L-cysteine functionalized Fe₃O₄ magnetic nanoparticles (Cys–Fe₃O₄ MNPs) were continuously fabricated by a simple high-gravity reactive precipitation method combined with surface modification through a novel impinging stream-rotating packed bed with the assistance of sonication. The obtained Cys–Fe₃O₄ MNPs was characterized by XRD, TEM, FTIR, TGA and VSM, and further used for the removal of heavy metal ions from aqueous solution. The influence of pH values, contact time and initial metal concentration on the adsorption efficiency were investigated. The results revealed that the adsorption of Pb(II) and Cd(II) were pH dependent process, and the pH 6.0 was found to be optimum condition. Moreover, the adsorption kinetic for Cys–Fe₃O₄ MNPs followed the mechanism of the pseudo-second order kinetic model, and their equilibrium data were fitted with the Langmuir isothermal model well. The maximum adsorption capacities calculated from Langmuir equation were 183.5 and 64.35 mg g⁻¹ for Pb(II) and Cd(II) at pH 6.0, respectively. Furthermore, the adsorption and regeneration experiment showed there was about 10% loss in the adsorption capacity of the as-prepared Cys–Fe₃O₄ MNPs for heavy metal ions after 5 times reuse. All the above results provided a potential method for continuously preparing recyclable adsorbent applied in removing toxic metal ions from wastewater through the technology of process intensification.     

Adsorption of Cu2+ Cations from Aqueous Solution by S-doped TiO2

S-doped TiO₂ as a novel adsorbent for Cu²⁺ cations removal from aqueous solutions was synthesized by simple sol-gel process. Removal of Cu²⁺ cations from aqueous solutions was investigated with particular reference to the effects of initial Cu²⁺ cations concentration, pH-value, adsorbent dosage, and temperature on adsorption. It was found that the maximum adsorption capacity was 96.35 mg g^?1 at 328 K. The adsorption equilibrium isotherms and the kinetic data were well described by the Langmuir and pseudo-second-order kinetic models, respectively. The high uptake capability of S-doped TiO₂ makes it a potentially attractive adsorbent for the removal of heavy metal pollutants from aqueous solution.     

Adsorption behavior of fluoride ions using a titanium hydroxide-derived adsorbent

The removal behavior of fluoride ions was examined in aqueous sodium fluoride solutions using a titanium hydroxide-derived adsorbent. The adsorbent was prepared from titanium oxysulfate (TiOSO₄·xH₂O) solution, and was characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry-differential thermal analysis, Fourier transform infrared spectrum and specific surface area. Batchwise adsorption test of prepared adsorbent was carried out in aqueous sodium fluoride solutions and real wastewater containing fluoride ion. The absorbent was the amorphous material, which had different morphology to the raw material, titanium oxysulfate, and the specific surface area of the adsorbent (96.8 m²/g) was 200 times higher than that of raw material (0.5 m²/g). Adsorption of fluoride on the adsorbent was saturated within 30 min in the solution with 200 mg/L of fluoride ions, together with increasing pH of the solution, due to ion exchange between fluoride ions in the solution and hydroxide ions in the adsorbent. Fluoride ions were adsorbed even in at a low fluoride concentration of 5 mg/L; and were selectively adsorbed in the solution containing a high concentration of chloride, nitrate and sulfate ions. The adsorbent can remove fluoride below permitted level (< 0.8 mg/L) from real wastewaters containing various substances. The maximum adsorption of fluoride on the adsorbent could be obtained in the solution at about pH 3. After fluoride adsorption, fluoride ions were easily desorbed using a high pH solution, completely regenerating for further removal process at acidic pH. The capacity for fluoride ion adsorption was almost unchanged three times after repeat adsorption and desorption. The equilibrium adsorption capacity of the adsorbent used for fluoride ion at pH 3 was measured, extrapolated using Langmuir and Freundlich isotherm models, and experimental data are found to fit Freundlich than Langmuir. The prepared adsorbent is expected to be a new inorganic ion exchanger for the removal and recovery of fluoride ions from wastewater.     

Removal of Cr(VI) from aqueous solution using amino‐modified Fe3O4–SiO2–chitosan magnetic microspheres with high acid resistance and adsorption capacity

A novel, bioadsorbent material of polyethylenimine‐modified magnetic chitosan microspheres enwrapping magnetic silica nanoparticles (Fe₃O₄–SiO₂–CTS‐PEI) was prepared under relatively mild conditions. The characterization results indicated that the adsorbent exhibited high acid resistance and magnetic responsiveness. The Fe₃O₄ loss of the adsorbent was measured as 0.09% after immersion in pH 2.0 water for 24 h, and the saturated magnetization was 11.7 emu/g. The introduction of PEI obviously improved the adsorption capacity of Cr(VI) onto the adsorbent by approximately 2.5 times. The adsorption isotherms and kinetics preferably fit the Langmuir model and the pseudo‐second‐order model. The maximum adsorption capacity was determined as 236.4 mg/g at 25°C, which was much improved compared to other magnetic chitosan materials, and the equilibrium was reached within 60 to 120 min. The obtained thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption process. Furthermore, the Cr(VI)‐adsorbed adsorbent could be effectively regenerated using a 0.1 mol/L NaOH solution, and the adsorbent showed a good reusability. Due to the properties of good acid resistance, strong magnetic responsiveness, high adsorption capacity, and relatively rapid adsorption rate, the Fe₃O₄–SiO₂–CTS‐PEI microspheres have a potential use in Cr(VI) removal from acidic wastewater. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43078.     

Adsorption of Cr(VI) on Cross‐Linked Chitosan Beads

Abstract

A possibility of Cr(VI) removal by the adsorption method is discussed in the paper. An adsorbent were hydrogel chitosan beads are produced by the phase inversion method (by changing pH). The possibility of removing Cr(VI) ions by both pure chitosan hydrogel and its chelate compounds (chitosan cross‐linked with Cu(II) and Ag(I) ions) was investigated. The adsorption proceeded from the solutions of potassium dichromate and ammonium dichromate (NH₄)₂Cr₂O₇ and K₂Cr₂O₇. The process rates and adsorption isotherms were determined and described by relevant equations. The process rate was described by the pseudo‐ and second‐order equations, and adsorption equilibria by the Langmuir equations. A slight advantageous change in adsorption properties of chitosan beads was revealed after cross‐linking (for chromium concentration up to 10 g/dm³). A maximum adsorption was 1.1 g_Cr/g chitosan. Results of the studies show that chitosan hydrogel proves useful in the removal of Cr(VI) ions, additionally, cross‐linking with Cu(II) and Ag(I) ions has an advantageous effect in the case of low‐concentrated solutions.     

Electron Beam Grafted Polymer Adsorbent for Removal of Heavy Metal Ion from Aqueous Solution

Abstract

An electron beam grafted adsorbent was synthesized by post irradiation grafting of acrylonitrile (AN) on to a non‐woven thermally bonded polypropylene (PP) sheet using 2 MeV electron beam accelerator. The grafted poly(acrylonitrile) chains were chemically modified to convert a nitrile group to an amidoxime (AMO) group, a chelating group responsible for metal ion uptake from an aqueous solution. The effect of various experimental variables viz. dose, dose rate, temperature, and solvent composition on the grafting extent was investigated. PP grafted with the amidoxime group (AMO‐g‐PP) was tested for its suitability as an adsorbent for removal of heavy metal ions such as Co²⁺, Ni²⁺, Mn²⁺, and Cd²⁺ from aqueous solution. Langmuir and Freundlich adsorption models were used to investigate the type of adsorption of these ions. The adsorption capacities of the adsorbent for the metal ions were found to follow the order Cd²⁺>Co²⁺>Ni²⁺>Mn²⁺. The kinetics of adsorption of these ions indicated that the rate of adsorption of Cd²⁺ was faster than that of other ions studied.     

The adsorption of malachite green (MG) as a cationic dye onto functionalized multi walled carbon nanotubes

Synthetic dyes are widely used by several industries to color their products. The discharge of colored wastewater into the hydrosphere causes serious environmental problems. We used functionalized multi wall carbon nanotubes as an adsorbent for the adsorption of cationic dye, malachite green, from aqueous solution. Based on information provided by the Iranian Research Institute of Petroleum Industry, carbon nanotubes are produced using a chemical vapor deposition (CVD) technique. These as-received MWCNTs were functionalized by acid treatment. The remaining dye concentration was read by UV-visible absorption spectroscopy at maximum adsorption wavelength. The effect of different operational parameters such as contact time, pH of solution, adsorbent dose and initial dye concentration were studied. The results showed that by increasing of contact time, pH and adsorbent dose the removal of dye increased, but by increasing initial dye concentration, the removal efficiency decreased. Adsorption isotherms and kinetics behavior of f-MWCNTs for removal of malachite green was analyzed, and fitted to various existing models. The experimental data were well correlated with the Langmuir isotherm with a maximum adsorption capacity (q _m ) and regression coefficient (R²) of 142.85 mg/g and 0.997, respectively. The results of this study indicate that functionalized multi wall carbon nanotubes can be used as an effective adsorbent for the removal of dyes.     

Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>–β-cyclodextrin–Chitosan Bionanocomposite for Arsenic Removal from Aqueous Solution

The aim of this present work is to investigate the adsorption capacity, kinetics and mechanism of arsenite ion removal onto beta-Cyclodextrin–Chitosan–Fe₃O₄ nanocomposite (β-CD–CS–Fe₃O₄ nanocomposite) from aqueous solutions. Iron oxide nanoparticles (Fe₃O₄) were synthesized using the co-precipitation method and the nanocomposite was successfully prepared via the solution-blending method. The analysis to determine arsenite ion adsorption was carried out using ICP-MS by varying pH, contact time and arsenite concentration parameters. The sorption of arsenite was found to be dependent on pH, time and arsenite initial concentrations. The adsorption equilibrium was reached in the first 20 min with the maximum uptake of 96%. Adsorption data were fitted well to the Langmuir isotherm describing a monolayer adsorption mechanism and pseudo-second-order models for kinetic study. It was established that the β-CD–CS polymer blend grafted with Fe₃O₄ nanoparticles enhanced the adsorption capacity because of the complexation abilities of the multiple OH and NH₂ groups in the polymer backbone with metal ions. Subsequently, the mechanism of adsorption was investigated by studying the physicochemical properties of the adsorbent and the adsorbed species using the FTIR, TGA, DSC, XRD, SEM and TEM techniques. The characterizations before and after incorporations of the β-CD–CS composite with Fe₃O₄ nanoparticles showed well-improved properties for better adsorption of arsenite (As(III)) ions.     

Use of chitosan complex with aminophosphonic groups and cobalt for the removal of Sr2+ ions

We briefly describe the adsorbent performance of the chitosan complex with aminophosphonic groups and cobalt in the removal process of Sr²⁺ ions from aqueous solutions. The strontium adsorption was studied as a function of pH, contact time, and initial strontium concentration. Adsorption isotherms such as Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin were used to analyze the equilibrium data at different concentrations. The kinetics of the Sr²⁺ sorption was analyzed using the pseudo-first-order and pseudo-second-order kinetic models. The results clearly indicate that the chitosan complex with aminophosphonic groups and cobalt is an efficient adsorbent with respect to its capacity to absorb Sr²⁺ ions from aqueous solutions.     

Microwave preparation and properties of O-crosslinked maleic acyl chitosan adsorbent for Pb2+ and Cu2+

A novel chitosan-based adsorbent (CCTM) was prepared by the reaction of epichlorohydrin O-crosslinked chitosan with maleic anhydride under microwave irradiation. The chemical structure of this polymer was characterized by infrared spectroscopy and X-ray diffraction analyses. The effects of various variables such as degree of substitution, adsorption time, initial metal ion concentration, solution pH, and temperature, on the adsorption of Pb²⁺ and Cu²⁺ by CCTM were investigated. The results demonstrate that the microwave irradiation can remarkably enhance the reaction. CCTM has higher adsorption capacity than chitosan. The maximum adsorption capacities for Pb²⁺ and Cu²⁺, with initial concentrations of 0.02 mol L⁻¹ at pH 5, are 246.3 and 132.5 mg g⁻¹, respectively. The adsorbent can be recycled. These results have important implications for the design of effective chitosan-based adsorbents in the removal of heavy metal ions from wastewaters. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Single step modification of micrometer-sized polystyrene particles by electromagnetic polyaniline and sorption of chromium(VI) metal ions from water

This article describes a single-step reproducible approach for the surface modification of micrometer-sized polystyrene (PS) core particles to prepare electromagnetic PS/polyaniline–Fe₃O₄ (PS/PANi–Fe₃O₄) composite particles. The electromagnetic PANi–Fe₃O₄ shell was formed by simultaneous seeded chemical oxidative polymerization of aniline and precipitation of Fe₃O₄ nanoparticles. The weight ratio of PS to aniline was optimized to produce core–shell structure. PS/PANi–Fe₃O₄ composite particles were used as adsorbent for the removal of Cr(VI) via anion-exchange mechanism. The composite particles possessed enough magnetic property for magnetic separation. The adsorption was highly pH dependent. Adsorption efficiency reached 100% at pH 2 in 120 min when 0.05 g of composite particles was mixed with 30 mL 5 mg L⁻¹ Cr(VI) solution. The adsorption isotherm fitted best with Freundlich model and maximum adsorption capacity approached 20.289 mg g⁻¹ at 323 K. The prepared composite was found to be an useful adsorbent for the removal of soluble Cr(VI) ions. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47524.