Selective sorption of Fe(III) using modified forms of chitosan beads

Modified chitosan beads (CB) were prepared and used for the removal of Fe(III) ions from aqueous solution. The advantages of modified CB than raw CB have been explored. The sorption capacity (SC) of the modified forms of CB namely, protonated CB, carboxylated CB, and grafted CB were found to be 3533, 3905, and 4203 mg kg^?1, respectively, while the raw CB showed the SC of 2913 mg kg^?1 only. Batch adsorption studies were conducted to optimize various equilibrating conditions like contact time, pH, and coions. The sorbents were characterized by FTIR, WDXRF, and SEM with EDAX analysis. The sorption process has been explained with Freundlich and Langmuir isotherms. Thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were calculated to understand the nature of sorption. Modified CB are more selective for Fe(III) than Cu(II), which inturn higher than Cr(VI). A suitable mechanism for iron sorption onto modified CB was established. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Removal of Copper(II) and Zinc(II) from Aqueous Solutions Using a Lignocellulosic-Based Polymeric Adsorbent Containing Amidoxime Chelating Functional Groups

In this study, the adsorption of Cu(II) and Zn(II) ions from aqueous solutions onto amidoximated polymerized banana stem (APBS) has been investigated. Infrared spectroscopy was used to confirm graft copolymer formation and amidoxime functionalization. The different variables affecting the sorption capacity such as pH of the solution, adsorption time, initial metal ion concentration, and temperature have been investigated. The optimum pH for maximum adsorption was 10.5 (99.99%) for Zn²⁺ and 6.0 (99.0%) for Cu²⁺ at an initial concentration of 10 mg L^?1. Equilibrium was achieved approximately within 3 h. The experimental kinetic data were analyzed using pseudo-first-order and pseudo-second-order kinetic models and are well fitted with pseudo- second-order kinetics. The thermodynamic activation parameters such as ΔG^o, ΔH^o, and ΔS^o were determined to predict the nature of adsorption. The temperature dependence indicates an exothermic process. The experimental isotherm data were well fitted to the Langmuir model with maximum adsorption capacities of 42.32 and 85.89 mg g^?1 for Cu(II) and Zn(II), respectively, at 20°C. The adsorption efficiency was tested using industrial effluents. Repeated adsorption/regeneration cycles show the feasibility of the APBS for the removal of Cu(II) and Zn(II) ions from water and industrial effluents.     

Preparation and adsorption characters of Cu(II)-imprinted chitosan/attapulgite polymer

Using attapulgite (ATP) as matrix, chitosan (CS) as functional monomer, and introducing the surface ionimprinting concept, a new Cu(II)-IIP was prepared, and characterized by SEM, XRD and FT-IR. The adsorption of Cu(II) aqueous solution with Cu(II)-IIP was investigated by flame atomic adsorption spectroscopy (FAAS). The polymer has good selectivity for Cu(II) from competitive metal ions, and the selectivity coefficient of Cu(II) relation to Pb(II), Cd(II) was 78.45 and 82.44, respectively. Sorption equilibrium isotherms could be described by Langmuir and Freundlich models; the Freundlich isotherm has shown the best agreement with experimental data, and experimental value of maximum adsorption capacity for Cu(II) was 35.20 mg/g. The obtained thermodynamic parameter (ΔG ^o , ΔH ^o , ΔS ^o ) showed that the Cu(II) adsorption process is a spontaneous and endothermic process. The kinetic data showed that pseudo-second-order kinetic model agrees very well with the dynamic behavior for the sorption of Cu(II) onto Cu(II)-IIP.      

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     

Adsorption characterization of lead(II) and cadmium(II) on crosslinked carboxymethyl starch

The adsorption of Pb(II) and Cd(II) ions with crosslinked carboxymethyl starch (CCS) was investigated as function of the solution pH, contact time, initial metal‐ion concentration, and temperature. Isotherm studies revealed that the adsorption of metal ions onto CCS better followed the Langmuir isotherm and the Dubinin–Radushkevich isotherm with adsorption maximum capacities of about 80.0 and 47.0 mg/g for Pb(II) and Cd(II) ions, respectively. The mean free energies of adsorption were found to be between 8 and 16 kJ/mol for Pb(II) and Cd(II) ions; this suggested that the adsorption of Pb(II) and Cd(II) ions onto CCS occurred with an ion‐exchange process. For two‐target heavy‐metal ion adsorption, a pseudo‐second‐order model and intraparticle diffusion seem significant in the rate‐controlling step, but the pseudo‐second‐order chemical reaction kinetics provide the best correlation for the experimental data. The enthalpy change for the process was found to be exothermic, and the ΔS^θ values were calculated to be negative for the adsorption of Pb(II) and Cd(II) ions onto CCS. Negative free enthalpy change values indicated that the adsorption process was feasible. The studies of the kinetics, isotherm, and thermodynamics indicated that the adsorption of CCS was more effective for Pb(II) ions than for Cd(II) ions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Adsorption Characteristics of Atrazine on Granulated Activated Carbon and Carbon Nanotubes

Adsorption of atrazine (ATZ) from aqueous solutions by granular activated carbon (GAC) and carbon nanotubes (CNT) was studied in a batch‐mode adsorption system at different initial concentrations of ATZ (1.0–30.0 mg L^–1) and at three temperatures of 288, 296 and 304 K. The adsorption isotherms of Langmuir, Freundlich, Polanyi–Manes, and Brunauer–Emmett–Teller (modified) were used to model the process. The adsorption kinetics followed a pseudo‐second‐order kinetic model. The thermodynamic parameters ΔH⁰, ΔS⁰, and ΔG⁰ of the adsorption were estimated. The thermodynamic parameters indicate that the adsorption process is spontaneous and exothermic.     

Functionalized sepiolite for heavy metal ions adsorption

Surface modification of clays has become increasingly important due to the practical applications of clays such as fillers and adsorbents. The surface modification of sepiolite with [3-(2-aminoethylamino)propyl]trimethoxysilane has been employed. The modified sepiolite surface was investigated by FTIR, XRD and DTA/TG analysis. It was found that the chemical bonding takes place between the hydroxyl groups and/or oxygen atoms within the structure of sepiolite and methoxy groups of [3-(2-aminoethylamino)propyl]trimethoxysilane. The changes on electrokinetic properties of modified sepiolite particles were studied by measuring the zeta potential of particle as a function of metal concentration and equilibrium pH of solution. It was found that the zeta potential of the clay particles was always negative independent of the metal concentration in solution. This study also provides some evidence for the adsorption of metal ions on modified sepiolite. The adsorption of metal ions onto modified sepiolite has varied with the type of metal cations. The available basic nitrogen centers covalently bonded to the sepiolite skeleton were studied for Co(II), Cu(II), Mn(II), Zn(II), Fe(III) and Cd(II) adsorption from aqueous solutions. It was found that the amount of metal ion adsorbed onto modified sepiolite increases with increase in solution equilibrium pH and temperature, whereas it generally decreases with the ionic strength. The experimental data were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (q_m and K) were calculated. The ability to adsorb the cations gave a capacity order of Zn(II) > Cu(II) ~ Co(II) > Fe(III) > Mn(II) > Cd(II) with affinities of 2.167×10⁻⁴, 1.870×10⁻⁴, 1.865×10⁻⁴, 1.193×10⁻⁴, 0.979×10⁻⁴ and 0.445×10⁻⁴ mol g⁻¹, respectively.     

Syntheses and adsorption properties for Hg2+ of chelating resin of crosslinked polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole

A novel chelating resin with functional group containing S and N atoms was prepared using chloromethylated polystyrene and 2,5‐dimercapto‐1,3,4‐thiodiazole (also called bismuththiol I, BMT) as materials. Its structure was characterized by infrared spectra and elementary analysis. The results showed that the content of the functional group was 2.07 mmol BMT g^?1 resin, 47% of which were in the form of monosubstitution (PS‐BMT‐1) and 53% in the form of double substitution (PS‐BMT‐2). The adsorption for mercury ion was investigated. The adsorption dynamics showed that the adsorption was controlled by liquid film diffusion. Increasing the temperature was beneficial to adsorption. The Langmuir model was much better than the Freundlich model to describe the isothermal process. The adsorption activation energy (E_a), ΔG, ΔH, and ΔS values calculated were 18.56 kJ·mol^?1, ‐5.99 kJ·mol^?1, 16.38 kJ·mol^?1, and 37.36, J·mol^?1·K^?1, respectively. The chelating resin could be easily regenerated by 2% thiourea in 0.1 mol·L^?1 HCl with higher effectiveness. Five adsorption–desorption cycles demonstrated that this resin was suitable for repeated use without considerable change in adsorption capacity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1646–1652, 2004     

Phosphate Removal from Aqueous Solution Using Coir-Pith Activated Carbon

The present study deals with the removal of phosphates from aqueous solution using activated carbon developed from coir pith. Batch adsorption experiments were performed to delineate the effect of initial pH, contact time, adsorbent dose and temperature on the removal of phosphates by coir-pith activated carbon (CAC) (activated by H₂SO₄). The removal was found to be maximum in the pH range of 6–10. The kinetics of adsorption showed that the phosphate adsorption onto CAC was a gradual process with a quasi-equilibrium being attained in 3 h. The adsorption equilibrium data followed the Temkin isotherm. Thermodynamic parameters such as ΔG ^o , ΔH ^o , and ΔS ^o were evaluated by applying the Arrhenius and van't Hoff equations, and it was found that the adsorption of phosphate on CAC was spontaneous and endothermic.     

New adsorbent material based on nitrothiophene-functionalized silica particles for aqueous heavy metals removal

Research of efficient materials is a well-established technology. In this work, a novel and excellent host, with sulfur donor atom, for heavy metals adsorption was synthesized by chemical immobilization of nitrothiophene receptor onto silica particles. The new adsorbent was well characterized by Brunauer–Emmett–Teller, Barrett-Joyner-Halenda, scanning electron microscopy, elemental analysis, FT-IR, and solid-state ¹³C nuclear magnetic resonance. The new surface exhibits good thermal stability determined by thermogravimetric analysis, and a good chemical stability as investigated in various acidic and buffer solutions. The adsorption properties were investigated using Cu(II), Pb(II), Cd(II), and Zn(II) metals by varying all relevant parameters including pH, contact time, concentration, temperature, kinetics, and Langmuir isotherms. The adsorption efficiency increases with increasing pH and follows pseudo-second-order kinetics. The maximum equilibrium time was found to be 30?min for all metal ions. The thermodynamic analysis (ΔH°, ΔS°, and ΔG°) revealed that the adsorption was endothermic and spontaneous.     

Reuse of a waste adsorbent poly(AAc/AM/SH)‐Cu superabsorbent hydrogel,for the potential phosphate ion removal from waste water: Matrix effects,adsorption kinetics,and thermodynamic studies

The most commonly applied methods for the treatment of used adsorbents is to recover them in acid/alkaline medium or direct enflame them. This work dealt with a new potential and economic method to utilize a waste adsorbent. Poly(AAc/AM/SH) superabsorbent hydrogels have proved to be a good adsorbent for Cu²⁺ ions and after adsorption the hydrogels were recovered in acid medium. In this report, the Cu²⁺ ion adsorbed hydrogel has not undergone any regeneration process and applied directly to phosphate ion adsorption. The Cu²⁺ ions‐loaded poly(AAc/AM/SH) hydrogels, were stable within a wide pH range and suitable for phosphate ion adsorption. The factors affecting the phosphate adsorption, such as pH, ionic strength, contact time, temperature, initial concentration of the phosphate ion, and coexisting ions were systematically investigated. The phosphate adsorption was highly pH dependent; and the maximum adsorption of 87.62 mg/g was achieved at pH 6.1. The adsorption data fitted the Langmuir adsorption isotherm better than the Freundlich isotherm. The concomitant anions show profounder adverse influence on phosphate ion adsorption of poly(AAc/AM/SH)‐Cu hydrogel and the effect follows the order citrate > sulfate > bicarbonate > chloride > nitrate. The thermodynamic parameters including ΔH°, ΔG°, and ΔS° for the adsorption processes of phosphate ions on the gel were also evaluated, and the negative ΔG° and ΔH° confirmed that the adsorption process was spontaneous and exothermic. The adsorption kinetic results suggest that the adsorption process was well described by the pseudo second‐order kinetic model. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Kinetic and equilibrium studies of Pb(II) and Cd(II) removal from aqueous solution onto colemanite ore waste

The adsorption characteristics of Pb(II) and Cd(II) onto colemanite ore waste (CW) from aqueous solution were investigated as a function of pH, adsorbent dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the adsorption isotherms. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The adsorption capacity of CW was found to be 33.6 mg/g and 29.7 mg/g for Pb(II) and Cd(II) ions, respectively. Analyte ions were desorbed from CW using both 1 M HCl and 1 M HNO₃. The recovery for both metal ions was found to be higher than 95%. The mean adsorption energies evaluated using the D-R model indicated that the adsorption of Pb(II) and Cd(II) onto CW were taken place by chemisorption. The thermodynamic parameters (ΔG^o, ΔH^o and ΔS^o) showed that the adsorption of both metal ions was feasible, spontaneous and exothermic at 20-50 °C. Adsorption mechanisms were also investigated using the pseudo-first-order and pseudo-second-order kinetic models. The kinetic results showed that the adsorption of Pb(II) and Cd(II) onto CW followed well pseudo-second order kinetics.     

Metal‐chelated polyamide hollow fibers for human serum albumin separation

We modified microporous polyamide hollow fibers by acid hydrolysis to amplify the reactive groups and subsequent binding of Cibacron Blue F3GA. Then, we loaded the Cibacron Blue F3GA‐attached hollow fibers with different metal ions (Cu²⁺, Ni²⁺, and Co²⁺) to form the metal chelates. We characterized the hollow fibers by scanning electron microscopy. The effect of pH and initial concentration of human serum albumin (HSA) on the adsorption of HSA to the metal‐chelated hollow fibers were examined in a batch system. Dye‐ and metal‐chelated hollow fibers had a higher HSA adsorption capacity and showed less nonspecific protein adsorption. The nonspecific adsorption of HSA onto the polyamide hollow fibers was 6.0 mg/g. Cibacron Blue F3GA immobilization onto the hollow fibers increased HSA adsorption up to 147 mg/g. Metal‐chelated hollow fibers showed further increases in the adsorption capacity. The maximum adsorption capacities of Co²⁺‐, Cu²⁺‐, and Ni²⁺‐chelated hollow fibers were 195, 226, and 289 mg/g, respectively. The recognition range of metal ions for HSA from human serum followed the order: Ni(II) > Cu(II) > Co(II). A higher HSA adsorption was observed from human serum (324 mg/g). A significant amount of the adsorbed HSA (up to 99%) was eluted for 1 h in the elution medium containing 1.0M sodium thiocyanide (NaSCN) at pH 8.0 and 25 mM ethylenediaminetetraacetic acid at pH 4.9. Repeated adsorption–desorption processes showed that these metal‐chelated polyamide hollow fibers were suitable for HSA adsorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3346–3354, 2002     

Kinetic,thermodynamic and equilibrium studies on the removal of copper ions from aqueous solutions by natural and modified clinoptilolites

This paper presents the adsorption of Cu(II) ions from aqueous solution on Na and Fe-modified clinoptilolite. The copper adsorption experiments were performed in a batch system considering an optimum contact time of 24 h. Changes in the surfaces and structure were characterized by SEM data. According to the SEM results, it was anticipated that the removal efficiency of Fe-modified clinoptilolite was the highest compared with the natural and Na-modified clinoptilolites. Adsorption of Cu(II) ions by modified clinoptilolites was investigated as a function of the initial Cu(II) concentration, solution pH, and temperature. According to the results, the maximum adsorbed Cu amount onto Fe-modified was 19.40mg/l at the optimum operating condition with a pH value of 5.5 and temperature of 60 °C. According to the thermodynamic evaluations, positive ΔS and negative ΔG were found for the adsorption process showing that the adsorption reaction is a spontaneous process and more favorable at high temperatures. Sorption data have been interpreted in terms of Langmuir and Freundlich, Temkin and Dubinin-Radushkevich. The adsorption equilibrium was best described by the Langmuir adsorption isotherm. In addition, according to the Sips model, the sorption of Cu(II) ions on the Fe-modified clinoptilolite was found to be heterogeneous. The kinetic study showed that the Fe-modified clinoptilolite followed the pseudo-second order model. The results indicated that the clinoptilolite-rich tuff in its iron oxide form could be efficiently used for the removal of copper from aqueous solutions.     

Synthesis of crosslinked oxidized starch and its adsorption behavior for calcium ion

Cornstarch, after crosslinking with epichlorohydrin (4%, v/w, dry basis of the starch), was oxidized with hydrogen peroxide over the catalyst Cu(II). The newly synthesized products were applied to examine the calcium ion removal activity from water, under various conditions. Removal efficiency of calcium ion from aqueous solution increased proportionally with carboxyl content and the dose of crosslinked oxidized starch in the solution. Ionization of carboxyl groups in starch was necessary for the effective calcium removal. When the pH of the solution was adjusted below 4.0, the starch was no longer an effective calcium‐sequestering agent. Adsorption isotherm models were developed, wherein the best fit was obtained in the Langmuir model. Thermodynamic study indicated that the adsorption process was exothermic, and the enthalpy change (ΔH^θ), the entropy change (ΔS^θ), and free energy change (ΔG^θ) of the adsorption process were calculated with adsorption isotherm data and basic thermodynamic relations. It was assessed that adsorption occurred by strong electrostatic interactions with the negative adsorption enthalpy (ΔH^θ). The regeneration and reusability of oxidized starch were also assessed and were found to retain the adsorption capacity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1539–1546, 2006     

Adsorption of Cu(II) ions from aqueous solutions on modified chrysotile: Thermodynamic and kinetic studies

The adsorption of Cu(II) ions by modified chrysotile from aqueous solution was investigated under different experimental conditions. The Langmuir and Freundlich equations were introduced to describe the linear forms about the adsorption of Cu(II) ions on the surface of modified chrysotile, and it was found that the adsorption equilibrium process was well described by the Langmuir isotherm model with the maximum adsorption capacity of 1.574 mmol/g at 333 K. The thermodynamic parameters (ΔG⁰, ΔH⁰ and ΔS⁰) for adsorption on modified chrysotile were also determined from the temperature dependence. The influences of specific parameters such as temperature, pH value and initial concentration for the kinetic studies were also examined. The adsorption follows a pseudo-second order rate law.     

Water purification of removal aqueous copper (II) by as-grown and modified multi-walled carbon nanotubes

This study compares aqueous copper (II) adsorbed onto as-grown and modified carbon nanotubes (CNTs), using H₂SO₄ and H₂SO₄/KMnO₄ processes. H₂SO₄ and H₂SO₄/KMnO₄ modifications reduced pH_iep and Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed that some functional groups were formed on modified CNTs. The adsorption capacity of copper (II) onto modified CNTs was greater than that of as-grown CNTs, especially at pH 6. The results demonstrate that the modified processes increased the adsorption capacity because the functional groups were generated on the modified surfaces of the CNTs. Additionally, the adsorption capacity of copper (II) onto as-grown and modified CNTs both increased with temperature, and the results indicated that the Langmuir isotherm fitted the experimental data well. Simulation results indicated that the ΔH⁰ values of as-grown, H₂SO₄-modified CNTs and H₂SO₄/KMnO₄-modified CNTs were 4.83, 14.37 and 29.92 kJ/mol, respectively. Based on ΔH⁰, the adsorption of Cu²⁺ onto H₂SO₄/KMnO₄-modified CNTs is suggested to proceed simultaneously by physisorption and chemisorption but that onto as-grown and H₂SO₄-modified CNTs may proceed only by physisorption.     

Studies on two‐dimensional coordination polymer cadmium phosphate and its high efficient adsorption of Pb(II) ions from aqueous solutions

The two‐dimensional coordination polymer cadmium phosphate with the morphology of rectangle layers was prepared by solid‐state template reaction at room temperature, and was characterized by XRD, FTIR, and TEM techniques. The as‐synthesized sample is a layered cadmium phosphate material, in which the structure is poly (CdPO₄^?) anion framework with ammonium ions and water species residing in the space between the layers, and cadmium ions are coordinated by the phosphate oxygen atoms. This article also presents the adsorption of Pb(II) ions from aqueous solution on the as‐synthesized coordination polymer cadmium phosphate, and the results showed that this inorganic polymer adsorbent had good adsorption capacity. It could reach to the saturation adsorption capacity within an hour, and its excellent adsorption capacity for Pb(II) was 5.50 mmol/g when the initial solution concentration was 1.68 × 10³ μg/mL at T = 278K. Moreover, the adsorption kinetics and adsorption isotherms were studied, it revealed that the adsorption kinetics can be modeled by pseudo second‐order rate equation wonderfully. The apparent activation energy (E_a), ΔG, ΔH, and ΔS were 3.16 kJ mol^?1, ?13.97 kJ mol^?1, ?11.84 kJ mol^?1, and 7.66 J mol^?1 K^?1, respectively. And it was found that Langmuir equation could well interpret the adsorption of the as‐synthesized coordination polymer cadmium phosphate for Pb(II) ions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Syntheses and characterization of polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole and its sorption behavior for Pd(II), Pt(IV), and Au(III)

A type of chelating resin crosslinking polystyrene‐supported 2,5‐dimercapto‐1,3,4‐thiodiazole (also called bismuththiol I, BMT), containing sulfur and nitrogen atoms, was prepared. The structure of PS‐BMT was confirmed by FTIR, elemental analysis, and X‐ray photoelectron spectroscopy (XPS). Adsorption of Pd(II), Pt(IV), and Au(III) was investigated. The capacity of PS‐BMT to adsorb Pd(II) and Pt(IV) was 0.190 and 0.033 mmol/g, respectively. The adsorption dynamics of Pd(II) showed that adsorption was controlled by liquid film diffusion and that the apparent activation energy, E_a, was 32.67 kJ/mol. The Langmuir model was better than the Freundlich model in describing the isothermal process of Pd(II), and the ΔG, ΔH, and ΔS values calculated were ?0.33 kJ/mol, 26.29 kJ/mol, and 87.95 J mol^?1 K^?1, respectively. The mechanisms of adsorption of Pd(II), Pt(IV), and Au(III) were confirmed by XPS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 631–637, 2006     

Removal of Cu(II), Fe(III), and Cr(III) from Aqueous Solution by Aniline Grafted Silica Gel

Abstract

The aniline moiety was covalently grafted onto silica gel surface. The modified silica gel with aniline groups (SiAn) was used for removal of Cu(II), Fe(III), and Cr(III) ions from aqueous solution and industrial effluents using a batch adsorption procedure. The maximum adsorption of the transition metal ions took place at pH 4.5. The adsorption kinetics for all the adsorbates fitted better the pseudo second‐order kinetic model, obtaining the following adsorption rate constants (k₂): 1.233 · 10^?2, 1.902 · 10^?2, and 8.320 · 10^?3 g · mg^?1 min^?1 for Cr(III), Cu(II), and Fe(III), respectively. The adsorption of these transition metal ions were fitted to Langmuir, Freundlich, Sips, and Redlich‐Peterson isotherm models; however, the best isotherm model fitting which presented a lower difference of the q (amount adsorbed per gram of adsorbent) calculated by the model from the experimentally measured, was achieved by using the Sips model for all adsorbates chosen. The SiAn adsorbent was also employed for the removal of the transition metal ions Cr(III) (95%), Cu(II) (95%), and Fe(III) (94%) from industrial effluents, using the batch adsorption procedure.