Poly(acrylamide/laponite) nanocomposite hydrogels: Swelling and cationic dye adsorption properties

Super adsorbent polyacrylamide (PAAm)/nanoclay (laponite, Lap) hydrogels were prepared by in situ free radical polymerization of AAm in an aqueous solution with clay as a crosslinker. The swelling properties and water‐soluble cationic dye adsorption behaviors of the PAAm/laponite (PAAm/Lap) nanocomposite (NC) hydrogels were investigated. The parameters of swelling and diffusion of water in dye solutions were evaluated for the PAAm/Lap NC hydrogels. The adsorption behavior of the monovalent cationic dyes such as Basic Blue 12 (BB 12), Basic Blue 9 (BB 9), and Basic Violet 1 (BV 1), were studied on the NC hydrogels. The effects of the clay content of the hydrogel on its cationic dye uptake behavior were studied. The adsorption studies indicated that the rates of dye uptake by the NC hydrogels increased in the following order: BB 9 > BB 12 > BV 1. This order is similar to the swelling results of the PAAm/Lap NC hydrogel in the dye solutions. The equilibrium uptakes of the different dyes by the PAAm/Lap NC hydrogel were nearly the same. In the dye absorption studies, S‐type adsorption in the Giles classification system was found for the BB 12 and BV 1 dyes, whereas L ‐type was observed for the BB 9 dye. After the heat treatment of PAAm/Lap, the rate of dye uptake and equilibrium dye uptake were increased. The NC hydrogels may be considered as a good candidate for environmental applications to retain more water and to remove dyes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Interaction of some cationic dyes with acrylamide/itaconic acid hydrogels

Acrylamide/itaconic acid (AAm/IA) hydrogels prepared by irradiating with γ radiation were used in experiments on uptake of some cationic dyes such as union green B (UG-B), basic blue 17 (BB-17), basic red 2 (BR-2), and lauths violet (LV). Adsorption of the cationic dyes onto AAm/IA hydrogels is studied by batch adsorption technique at 25°C. In the experiments of the adsorption, Langmiur type adsorption in the Giles classification system was found. Some binding and thermodynamic parameters for AAm/IA hydrogel-dye systems were calculated by using Klotz method. Adsorption studies indicated that monolayer coverages of AAm/IA hydrogel by these dyes were increased with following order BB-17 > UG-B > BR-2 > LV. © 1996 John Wiley & Sons, Inc.     

Swelling and dye adsorption study of novel superswelling [Acrylamide/N-vinylpyrrolidone/3(2-hydroxyethyl carbamoyl) acrylic acid] hydrogels

Summary Super swelling acrylamide (Am)/N-vinylpyrrolidone (NVP)/3-(2-hydroxyethyl carbamoyl) acrylic acid (HECA) hydrogels were prepared by free radical polymerization of quaternary mixtures of Am, NVP, HECA and water. The hydrogels were used in experiments on swelling, diffusion and adsorption of some water-soluble monovalent cationic dyes such as Crystal Violet (CV), Malachite Green (MG) and Methylene Blue (MB). In the experiment of the adsorption of dyes from their aqueous solutions type-S adsorption isotherm were found. The diffusion of water within the hydrogel was found to have non Fickian character. The uptake of dyes within the hydrogel increased in the following order: MG > MB > CV. The binding ratio of the hydrogel/dye systems was gradually increased with the increase of HECA content in the AAm/NVP/HECA hydrogel.     

The usability of (sodium alginate/acrylamide) semi-interpenetrating polymer networks on removal of some textile dyes

In this study, (sodium alginate/acrylamide) interpenetrating polymer networks ((NaAlg/AAm)IPN) have been prepared at definite composition. The aqueous solution of 3% (w/v) sodium alginate and 50% (w/v) acrylamide was irradiated with ⁶⁰Co-γ rays at a dose rate of 0.07 kGy/h up to 5 kGy. The percent conversion was determined gravimetrically and 100% gelation was achieved at 5 kGy dose. To understand whether the semi-interpenetrating polymer network of sodium alginate is performed, Fourier Transform Infrared (FTIR) spectra of polyacrylamide (PAAm), sodium alginate, and the semi-interpenetrating polymer network were recorded. It is found that the FTIR spectra of PAAm, NaAlg, and the semi-interpenetrating polymer network are different. The thermograms of PAAm, sodium alginate, and the semi-interpenetrating polymer network were recorded for investigating their thermal character. (NaAlg/AAm)IPN hydrogels were immersed to swell in a solution of pH 7, at a temperature of 25°C. The swelling results at pH 7.0 indicated that (NaAlg/AAm)IPN hydrogel, containing 3% NaAlg showed maximum % swelling in water but swelling increased in the order of water > Magenta > Methylene Blue > Safranine-O > Methyl Violet. Diffusion of water and aqueous solution of dyes within (NaAlg/AAm)IPN hydrogels was found to be of Fickian character at the initial stage of swelling with regard to values calculated for diffusion coefficient of (NaAlg/AAm)IPN hydrogels in water and aqueous solution of dyes. Some diffusion parameters were calculated from swelling of (NaAlg/AAm)IPN in water and dyes and their adsorption isotherms were plotted. In the adsorption experiments, the efficiency of (NaAlg/AAm)IPN hydrogels to adsorb Magenta, Safranine-O, Methylene Blue, and Methyl Violet dyes from water was studied. (NaAlg/AAm)IPN hydrogels showed different adsorption for different aqueous solution of dyes at pH 7.0. Adsorption isotherms were constructed for (NaAlg/AAm)IPN-dye systems. S type adsorption in the Giles classification system was found. Thermal and spectroscopic characterization of semi-interpenetrating polymer network of sodium alginate and acrylamide and dye adsorbed semi-interpenetrating polymer network of sodium alginate and acrylamide was recorded. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Use of superswelling acrylamide/maleic acid hydrogels for monovalent cationic dye adsorption

Acrylamide/maleic acid (AAm/MA) superswelling hydrogels prepared by irradiation with γ radiation were used in experiments on swelling, diffusion, and adsorption of some water‐soluble monovalent cationic dyes such as basic red 5 (BR‐5), basic violet 3 (BV‐3), and brilliant cresyl blue (BCB). The AAm/MA hydrogel containing 60 mg MA and irradiated at 5.20 kGy was used for swelling and diffusion studies in water and aqueous solutions of the monovalent cationic dyes. For this superswelling hydrogel the swelling studies indicated that swelling increased in the following order: BR‐5 > water > BV‐3 ≥ BCB. The diffusion of water and the dyes within the hydrogels was found to have a non‐Fickian character. The uptake of the cationic dyes to the AAm/MA superswelling hydrogels was studied by the batch adsorption technique at 25°C. The uptake of dyes within the hydrogel increased in the following order: BR‐5 > BV‐3 > BCB. In the experiments of the adsorption equilibrium, S‐type adsorption in Giles' classification system was found. The binding ratio of the hydrogel/dye systems was gradually increased with the increase of the MA content in the AAm/MA hydrogel and the irradiation dose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1809–1815, 2001     

A study on the adsorption of some cationic dyes onto acrylamide/itaconic acid hydrogels

Summary Acrylamide/itaconic acid (AAm/IA) hydrogels prepared by irradiating with radiation were used in experiments on the adsorption of some cationic dyes such as basic red 9 (BR 9), basic green 4 (BG 4), cresyl violet (CV), and basic blue 20 (BB 20). Adsorption of the cationic dyes onto AAm/IA hydrogels is studied by batch adsorption technique. In the experiments of the adsorption, Langmiur type adsorption in the Giles classification system was found. Monolayer coverages for AAm/IA hydrogel-dye systems were calculated by using B point method. Adsorption studies indicated that monolayer coverages of AAm/IA hydrogel by these dyes were increased with following order; BB 20>CV>BR9>BG 4.     

Radiation synthesis of hydrogels based on carboxymethyl cellulose and its application in removal of pollutants from wastewater

Synthesis of carboxymethyl cellulose‐g‐methacrylic acid/acrylamide Poly(CMC/MAAc:AAm) hydrogel was carried out using direct radiation copolymerization technique at ambient temperature. The gel (%) increased with increasing the content of AAm till level off at Poly(CMC/MAAc:AAm) (1/50:50 wt%) hydrogel and the swelling behavior found to be increased with increasing MAAc content in the hydrogel composition up to Poly(CMC/MAAc:AAm) (1/60:40 wt%). The grafting yield, grafting ratio, swelling behavior, and the thermal stability of Poly(CMC/MAAc:AAm) binary system are higher than those reported in our previous study by the same author which described the individual grafting of acrylamide (AAm) and methacrylic acid (MAAc) with different concentration onto carboxymethyl cellulose (CMC) using direct radiation grafting technique. The swelling kinetics and diffusion mechanism indicate that the water penetration obey non‐Fickian transport mechanism. The characterization of the prepared hydrogel was evaluated using Fourier transform infrared, X‐ray diffraction, thermogravimetric analysis, and scanning electron microscopy. The analyses by different analytical tools confirmed the successful grafting of both MAAc and AAm onto CMC. The adsorption capacity of Poly(CMC/MAAc:AAm) (1/60:40 wt%) hydrogel toward metal ions such as Cu⁺² and Co⁺², dyes such as acid blue dye and methyl green have been investigated. J. VINYL ADDIT. TECHNOL., 25:E35–E43, 2019. © 2017 Society of Plastics Engineers     

Synthesis of urethane sodium carboxylate and its dye removal ability from single system

Urethane sodium carboxylate (USC) was synthesized and its dye removal ability was investigated. USC characteristics were studied using FTIR and SEM. Basic Blue 41 (BB41), Basic Red 18 (BR18), and Basic Violet 16 (BV16) were used. The effect of adsorbent dosage, dye concentration and salt on dye removal was evaluated. Adsorption kinetics followed pseudo-second order. The USC adsorption capacity was 474, 538 and 298 mg/g for BB41, BR18 and BV16, respectively. Adsorption isotherm followed with Langmuir isotherm. The results showed that the USC might be a suitable adsorbent to remove dyes from colored wastewater.     

Synthesis of copolymeric hydrogels using gamma radiation and their utilization in the removal of some dyes in wastwater

Copolymer hydrogels were prepared by γ‐radiation copolymerization of maleic acid (MA) and 2‐hydroxyethylacrylate (HEA) or acrylamide (AAm). The effect of AAm/MA and HEA/MA composition and irradiation dose on the gel fraction yield in the prepared hydrogels was determined. It was found that as the content of MA increased, the gel fraction yield decreased. The increase of irradiation dose resulted in increasing the crosslinked network structure and consequently the gel percent. The parameters of equilibrium swelling, maximum swelling, initial swelling rate, diffusion exponent, and diffusion coefficient of the hydrogels were calculated and evaluated, and it was found that water diffusion to the hydrogels generally was a non‐Fickian diffusion type. Characterization of the prepared hydrogels was studied and accordingly the possibility of its practical use in the treatment of waste dyes from aqueous solution was studied. The effect of treatment time, the pH of the feed solution, initial feed concentration, and temperature on the dye uptake was also investigated. The maximum uptake of the investigated dyes was higher for HEA/MA hydrogel than that for AAm/MA hydrogel. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3720–3731, 2006     

A novel hydrogel based on agricultural waste for removal of hazardous dyes from aqueous solution and reuse process in a secondary adsorption

A novel hydrogel based on the orange peel (OP) and N-vinyl-2-pyrrolidone was prepared by free-radical polymerization using gamma irradiation. The effect of radiation dose and hydrogel composition on gel content was studied. The formed hydrogel was characterized by FT-IR, TGA, and SEM. The swelling behavior was determined as a function of swelling time, pH, and OP content. The hydrogel swelling was found to be pH dependent, and the diffusion mechanism of water into the hydrogel was found Fickian. The developed hydrogel was used for the removal of Congo red (CR) and methyl orange (MO) dyes from wastewater. The effects of various operating parameters, such as initial pH, contact time, initial dye concentration, and temperature on the removal of dyes, have been investigated. The Langmuir and the Freundlich adsorption models were applied to study the adsorption isotherm. The pseudo-first-order model was proved compatible for CR adsorption and the pseudo-second-order model well described the adsorption of MO. The adsorption of dyes increased with increasing temperature indicating that the endothermic nature of the adsorption process and the thermodynamic parameters was evaluated. Second, the adsorption cycle of dyes was also examined and discussed utilizing the loaded hydrogel with the other dye and cobalt metal ions.     

Factors affecting the adsorption of cationic dyes on polymeric hydrogels prepared by gamma irradiation

The adsorption of the cationic dyes Rhodamine B (RB) and Crystal Violet (CV) on polyacrylamide/poly(acrylic acid) (poly(AAm/AAc), 25:25 % weightwise) and polyacrylamide/poly(sodium acrylate) (poly(AAm/AAcNa), 25:25 % weightwise) hydrogels was studied, employing the Langmuir and Freundlich isotherms. The results of swelling tests at pH 5.5 indicate that poly(AAm/AAcNa) hydrogel shows maximum percentage swelling (%S) was 4400 %. Moreover, the results show that the adsorption capacity is pH‐ and concentration‐dependent. At pH >5 adsorption of RB and CV increases due to ionization of ? COOH and ? COONa groups of (poly(AAm/AAc) and (poly(AAm/AAcNa) and interactions with the cationic groups of the dyes. However, at pH lower than 5, adsorption is still high, which can be explained by considering the formation of hydrogen bonds between the amino groups of the dyes and the ? COOH groups of the polymeric hydrogels. Moreover, the kinetics of adsorption follows a first‐order equation. Furthermore, scanning electron microscopy (SEM) micrographs of polymeric hydrogels doped with CV and RB have morphological differences from the pure form. Our data show that Rhodamine B adsorbs more efficiently on both polyacrylamide/poly(acrylic acid) and polyacrylamide/poly(sodium acrylate) hydrogels than CV. Copyright © 2004 Society of Chemical Industry     

Radiation-induced grafting of acrylamide and methacrylic acid individually onto carboxymethyl cellulose for removal of hazardous water pollutants

Carboxymethyl cellulose hydrogels were synthesized by grafting of acrylamide (AAm) and methacrylic acid (MAAc) individually with different concentrations onto carboxymethyl cellulose (CMC) using direct radiation grafting technique. It was found that for both Poly(CMC/AAm) and Poly(CMC/MAAc), the grafting yield and grafting ratio increase with the increasing monomer concentration. Also, it is noted that both grafting ratio and grafting yield of Poly(CMC/AAm) are higher than that of Poly(CMC/MAAc). The effect of different monomer concentrations on gel (%) and swelling behavior was studied. It is found that the increasing monomer concentration increases gel (%). For Poly(CMC/AAm) hydrogels, the swelling behavior decreases with increasing AAm concentration due to high crosslinking hydrogel formation, while as MAAc content increases, swelling behavior increases up to Poly(CMC/MAAc) 1:25 wt%. Swelling kinetics and diffusion mechanism indicate that the water penetration obeys non-Fickian transport mechanism. The structures and properties of the original CMC and the prepared Poly(CMC/MAAc) and Poly(CMC/AAm) were characterized using different analytical tools such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM). This study provides a solution to the discharge of different pollutants from wastewater. The adsorption capacity of Poly(CMC/MAAc) and Poly(CMC/AAm) hydrogels toward heavy metals, Cu⁺² and Co⁺², dyes such as acid blue dye and methyl green, and organic contaminants such as 4-chlorophenol and 2,4-Dichlorophenoxy acetic acid has been investigated.     

Synthesis and characterization of Na‐alginate/acrylamide hydrogel and its application in dye removal

Sodium‐alginate/acrylamide (Na‐alginate/AAm) cross‐linked hydrogel was prepared by using gamma irradiation. The gel content and the water absorbency behavior of the obtained hydrogel were investigated. The thermal and morphological properties of the prepared hydrogel were studied using thermogravimetric analysis and scanning electron microscopy. The thermal stability of Na‐alginate significantly changed when mixed with AAm. The adsorption of basic violet 7 dye on the prepared hydrogel was studied under different experimental conditions. The adsorption process for the basic dye was proven pH dependent. The maximum amount adsorbed (mg/g) of the Na‐alginate/AAm for the dye was found to be 78.1.0 mg/g at pH 9.0. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In-Situ UV-Visible Spectroscopic Study on the Adsorption of some Dyes onto Activated Carbon Cloth

Abstract

Adsorptive removal of the dyes C.I. Basic Blue 9, C.I. Basic Red 2, and C.I. Acid Blue 74 from aqueous solution onto the activated carbon cloth (ACC) has been investigated. The removal of each dye has been followed by in-situ UV-visible spectroscopic method using the so-called scanning kinetics technique. Kinetic data obtained in this way were tested according to pseudo-first order, pseudo-second order, Elovich, and intraparticle diffusion models. Pseudo-second order model was found to be the best in representing the experimental kinetic data. Adsorption isotherms at 30°C were derived for each dye. Isotherm data were found to fit best to Freundlich isotherm model among the three isotherm models tested; Langmuir, Freundlich, and Redlich-Peterson. High specific surface area of the ACC allowed almost complete removal of each dye under the experimental conditions applied. Adsorption capacity of the ACC for the three dyes was correlated with the dimensions of dye molecules and pore sizes of the ACC.     

A New Sorbent Chemically Cross-linked Highly Swollen Copolymeric Hydrogels for Dye Uptake

Water uptake and the sorption properties of polyelectrolyte hydrogels made by the polymerization of acrylamide (AAm) with maleic acid (MA) were investigated as a function of composition to find materials with swelling and dye sorption properties. Highly swollen acrylamide/maleic acid (AAm/MA) hydrogels were prepared by free radical solution polymerization in aqueous solutions of AAm with MA as comonomer and two multifunctional cross-linkers such as trimethylolpropane triacrylate (TMPTA) and 1,4-butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25°C, gravimetrically. Chemically cross-linked AAm/MA hydrogels were used in experiments on sorption of water-soluble monovalent cationic dyes such as “Nil blue” (NB) and “Methyl violet (MV)”. Weight-swelling ratio values of AAm/MA hydrogels were calculated range 8.88–61.46. Some swelling kinetic parameters were found. Diffusion behavior of water and water sorption rate constant were investigated. Water diffusion into hydrogels was found to be non-Fickian in character. For sorption of cationic dyes, NB and MV into AAm/MA hydrogels were studied by batch sorption technique at 25°C. AAm/MA hydrogels in the dye solutions showed coloration. However, the AAm hydrogel did not show sorption of any dye from solution. The amount of the dye sorbed per unit mass of AAm/MA hydrogels was investigated.     

Binding of some dyes onto crosslinked poly (N-vinylpyrrolidone)

Summary Bindings of some anionic dyes containing sulfonyl group(s), namely, Acid Blue 74 (AB-74), Acid Orange 7 (AO-7), Acid Green 1 (AG-1), Direct Blue 53 (DB-53), and Calconcarboxylic acid (CCA) onto crosslinked poly(N-vinylpyrrolidone) (CPVP) have been investigated using adsorption isotherm parameter. The dyes were linked positively charged on the tertiary nitrogen atom on the pyrrolidone ring in polymer chain resulting keto-enol tautomerism from sulfonyl group on the benzene ring in the dyes molecules. In the experiments of adsorption, L (Langmuir) type adsorption in the Giles classification system was found. Monolayer coverages (n) of polymer/dye system were founds by "B point" methods. Adsorption studies indicated that monolayer coverages of CPVP by the anionic dyes containing sulfonyl group(s) were increased with following order; CCA > AG-1 >> DB-53 > AO-7 > AB-74. Received: 10 April 2000/Revised version: 26 May 2000/Accepted: 6 June 2000     

Interaction of nicotine and its pharmaceutical derivatives with acrylamide/itaconic acid hydrogels

Acrylamide/itaconic acid hydrogels (AAm/IA) containing different amounts of itaconic acid prepared by irradiating with γ radiation were used in experiments on swelling, diffusion, and interactions of the pharmaceuticals nicotine, nicotinic acid, nicotinamide, and nikethamide. AAm/IA hydrogel containing 60 mg itaconic acid and irradiated at 4.65 kGy has been used for swelling and diffusion studies in water and aqueous solutions of the pharmaceuticals. For this hydrogel, swelling studies indicated that swelling increased with the following order: water > nicotine > nikethamide > nicotinamide > nicotinic acid. Diffusions of water and the pharmaceuticals within hydrogels were found to be non-Fickian in character. The uptake of the pharmaceuticals to AAm/IA hydrogels was studied by batch adsorption technique at 25°C. In the experiments of the adsorption, C-type adsorption in Giles's classification system was found. Some binding and thermodynamic parameters for AAm/IA hydrogel-pharmaceutical systems were calculated by using the Klotz method. The values of adsorption heat, free energy, and entropy of this system were found as negative values. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 733–739, 1997     

Isotherm,Kinetic, and Thermodynamic of Cationic Dye Removal from Binary System by Feldspar

In this paper, the isotherm, kinetic, and thermodynamic of cationic dye removal onto inorganic adsorbent (Feldspar) were investigated in single and binary systems. Basic Red 18 (BR18) and Basic Blue 41 (BB41) were used as cationic dyes. The characterization of the Feldspar was carried out using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques. The effect of operational parameters such as adsorbent dosage, initial dye concentration, pH, ionic strength, and temperature on dye removal was studied. It was found that the adsorption of BR18 and BB41 onto Feldspar followed with Langmuir and extended Langmuir isotherms in single and binary systems, respectively. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetic in single and binary system. The thermodynamic data showed that dye adsorption onto Feldspar was spontaneous, endothermic, and physisorption reaction. Based on the data of the present investigation, one could conclude that the Feldspar as an eco-friendly and low-cost adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions containing cationic dyes.     

Adsorption of Several Dyes from Aqueous Solutions on Silica-Containing Complex-Oxide Gels

Abstract

Removal of dyes from aqueous solutions was investigated in a batchwise operation using binary or ternary silica-containing complex-oxide gels as adsorbents. The following three combinations of gels showed the best results: (1) silica-titania-magnesia gel for C.I. Acid Blue 40, (2) silica-titania gel for C.I. Basic Blue 3, and (3) silica-titania gel treated with alkali for C.I. Reactive Red 5. The adjustment of the initial pH of the dye solution was effective in all cases. Freundlich-type adsorption isotherms related the amount of dye adsorbed to its equilibrium concentration in solution. The gels which adsorbed the dye abundantly were effectively regenerated for reuse by heating them at 600°C, which caused decomposition of the dye.     

Equilibrium Swelling Characterization and Dye Uptake Studies of Acrylamide-co-Methylenesuccinic Acid Hydrogels and Semi-IPNs with PEG

A novel semi-interpenetrating network hydrogel, composed of acrylamide with methylenesuccinic acid as comonomer, with poly (ethylene glycol) and trimethylolpropane triacrylate was prepared. Highly swollen hydrogels were synthesized by free radical polymerization. Swelling experiments were performed in water and dye solutions at 25°C. The hydrogels were used in experiments on sorption of Basic Blue 12. Water and Basic Blue 12 diffusion into hydrogels was found to be non-Fickian in character. For sorption of BB 12 into the hydrogels was studied by batch sorption technique at 25°C. The adsorption capacity, removal effiency and partition coefficient of the hydrogels was investigated.