Semiha Kundakci

Water Sorption and Dye Uptake Studies of Highly Swollen AAm/AMPS Hydrogels and Semi-IPNs with PEG

A semi-interpenetrating network (semi-IPNs) hydrogel, composed of acrylamide (AAm) with 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as co-monomer, with poly(ethylene glycol) (PEG) and two multifunctional cross-linkers such as 1,4-butanediol dimethacrylate (BDMA), and trimethylolpropane triacrylate (TMPTA) was prepared. AAm/AMPS hydrogels and AAm/AMPS/PEG semi-IPNs were synthesized by free radical solution polymerization. Swelling experiments were performed in water at 25°C, gravimetrically. For sorption of Toluidin Blue (Basic Blue 17, TB) into AAm/AMPS hydrogels and AAm/AMPS/PEG semi-IPNs was studied by batch sorption technique at 25°C. Dye removal capacity, removal effiency and partition coefficient of the hydrogels was investigated.

A Novel Polymeric Adsorbent for Water and Dye Uptake: Acrylamide/Sodium Acrylate Copolymers and Semi-Interpenetrating Polymer Networks Composed of Gelatin and/or PVA

Gelatin (GEL) and poly (vinyl alcohol) (PVA)-based semi-interpenetrating polymer network (semi-IPN) hydrogels were prepared for cationic dye sorption. Chemically cross-linked copolymer of acrylamide/sodium acrylate (AAm/SA) with PVA and/or GEL were prepared by polymerization of aqueous solution of AAm, and SA using ammonium persulphate/N,N,N’,N’-tetramethylethylenediamine as redox initiating pair in presence of poly(ethylene glycol)diacrylate as cross-linker. FTIR analysis was used for structural characterization. Surface morphology was characterized by SEM. Methyl violet has been used in sorption studies. Water uptake, and dye sorption properties of the cross-linked polymeric systems were investigated as a function of chemical composition of the hydrogels.

Uranyl Ion Uptake from Aqueous Solutions by Chemically Cross-linked Polyelectrolyte CAMA Hydrogels

Uranyl ion adsorption from aqueous solutions has been investigated by chemically cross-linked polyelectrolyte acrylamide/maleic acid (CAMA) hydrogels. CAMA hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), maleic acid (MA), and water by free radical polymerization in aqueous solution using multifunctional cross-linkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4-butanediol dimethacrylate (BDMA). Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of adsorbent on the uranyl ion adsorption were examined. In the experiments of the sorption, L type sorption in the Giles classification system was found. Some binding parameters such as initial binding constant (K i ), equilibrium constant (K), monolayer coverage (n), site-size (u), and maximum fractional occupancy (Ô) for CAMA hydrogel-uranyl ion binding system were calculated by using Langmuir linearization method. Finally, the amount of sorbed uranyl ion per gram of dry hydrogel (q) was calculated to be 3.29 × 10−4 − 15.87 × 10−4 mol uranyl ion per gram for CAMA hydrogels. Adsorption of uranyl ion was changed range 8.17–48.10%.

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.

Behaviors of Chemically Crosslinked CAAMPS Hydrogels in Uptake of Uranyl Ions from Aqueous Solutions

Uranyl ion adsorption from aqueous solutions has been investigated by chemically crosslinked (C) polyelectrolyte acrylamide/2-acrylamido-2-methyl-1-propanesulfonic acid (CAAMPS) hydrogels. CAAMPS hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and water by free radical polymerization in an aqueous solution using multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4 butanediol dimethacrylate (BDMA). The swelling equilibrium of polyelectrolyte copolymer gels containing of CAAMPS hydrogels has been studied as a function of copolymer composition. Swelling experiments were performed in water at 25°C, gravimetrically. The influence of AMPS content in hydrogels was examined. The weight-swelling ratio of CAAMPS hydrogels was increased up to 127.03 (for 300 mg AMPS and crosslinked by EGDMA) and 93.32 (for 300 mg AMPS and crosslinked by BDMA), while acrylamide hydrogels swelled up to 10.27 (crosslinked by EGDMA) and 10.06 (crosslinked by BDMA). Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of AMPS on the uranyl ion adsorption were examined. In the experiments of the sorption, L type sorption in the Giles classification system was found. Finally, the amount of sorbed uranyl ion per gram of dry hydrogel (q) was calculated to be 0.67 × 10−3–2.11 × 10−3 mol uranyl ion per gram for CAAMPS hydrogels. Removal effiency of uranyl ions (RE%) was changed range 9.05–29.92%. The values of partition ratio, (K d ) of uranyl ions was calculated to be 0.10–0.43 for CAAMPS hydrogels.

Highly Swollen Polymer/Clay Composite Sorbent-Based AAm/AMPS Hydrogels and Semi-IPNs Composed of Carboxymethyl Cellulose and Montmorillonite and Cross-Linked by PEGDA

New highly swollen hydrogel composite systems containing polysaccharide/clay polyelectrolyte based on the acrylamide/2-acrylamido-2-methyl-1-propanesulfonic acid and carboxymethyl cellulose and clay such as montmorillonite were synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N’,N’-tetramethylethylenediamine as a redox initiating pair in the presence of poly(ethylene glycol)diacrylate (PEGDA) as a cross-linker. FTIR analysis and scanning electron microscopy (SEM) techniques were applied for characterization. Some swelling and diffusion characteristics were calculated. The hydrogels were used in experiments on sorption of water-soluble cationic dye such as Lauths violet. For sorption of LV into the polymeric systems were studied by batch sorption technique at 25°C.

Swelling Characterization and Adsorptive Features of Acrylamide/Itaconic Acid Hydrogels and Semi-IPNs for Uranyl Ions

A novel semi-interpenetrating network (semi-IPNs) hydrogel, composed of acrylamide (AAm) with itaconic acid (ITA) as co-monomer, with poly (ethylene glycol)(PEG) and trimethylolpropane triacrylate (TMPTA) was prepared. Hydrogels and semi-IPNs were synthesized by free radical solution polymerization. Swelling experiments were performed in water and aqueous solutions of uranyl acetate. Diffusion behavior was investigated and their diffusion into hydrogels was found to be non-Fickian in character. Sorption of uranyl ion onto the polymeric system was studied by a batch sorption technique at 25°C. The sorption capacity, removal effiency and partition coefficient of the hydrogels were investigated.

Equilibrium Swelling Studies of Highly Swollen Acrylamide/Thiosinamine Hydrogels

Highly swollen water absorbent copolymers on acrylamide (AAm) and thiosinamine (ThA) have been studied as a function of copolymer composition. AAm/ThA hydrogels were prepared by free radical solution polymerization in aqueous solution of AAm with ThA as hydrophilic comonomer and two multifunctional crosslinkers such as 1,4 butanediol dimethacrylate (BDMA) and trimethylolpropane triacrylate (TMPTA). Swelling experiments were performed in water at 25°C, gravimetrically. The influence of ThA content in hydrogels was examined. Swelling of AAm/ThA hydrogels was increased up to 2156% (for containing 20 mg ThA and crosslinked by TMPTA) and 3139% (for containing 20 mg ThA and crosslinked by BDMA), while AAm hydrogels swelled up to 1155% (crosslinked by TMPTA) − 1417% (crosslinked by BDMA). The values of equilibrium water content of the hydrogels are 0.9203-0.9691. Diffusion behavior was investigated. Water diffusion into hydrogels was found to be non-Fickian in character.

Application of highly swollen novel biosorbent hydrogels in uptake of uranyl ions from aqueous solutions

The aim of this study was to investigate the equilibrium swelling and uranyl ion sorption properties of chemically crosslinked copolymeric hydrogels as biopotential sorbent consisting of acrylamide (AAm), sodium acrylate (SA), gelatin (GEL) and poly(ethylene glycol) (PEG). Semi-interpenetrating polymer network (semi IPNs) hydrogel, composed of AAm with SA as co-monomer, with PEG and GEL and a multifunctional crosslinker such as poly(ethylene glycol) diacrylate (PEGDA) was prepared by free radical solution polymerization by using ammonium persulphate (APS)/N,N,N′,N′-tetramethylethylenediamine (TEMED) as redox initiating pair. Swelling experiments were performed in water at 25 °C, gravimetrically. The hydrogels showed enormous swelling in water and displayed swelling characteristics that were highly depended on the chemical composition of the hydrogels. For characterization, FT-IR, thermogravimetric analysis (TG and DTG) and surface morphology (SEM) studies have been realized. FTIR spectroscopy was used to identify the presence of different repeating units in the semi IPNs. Some swelling and diffusion characteristics were calculated for different semi IPNs and hydrogels prepared under various formulations. For sorption studies, uranyl ion into the hydrogels was studied by batch sorption technique at 25 °C. Sorption capacity, removal effiency and partition coefficient of the hydrogels was investigated. Swelling and uranyl ion sorption properties of AAm/SA, AAm/GEL/SA, AAm/PEG/SA and AAm/GEL/PEG/SA hydrogel systems were investigated as a function of chemical composition of the hydrogels.

Novel composite sorbent AAm/MA hydrogels containing starch and kaolin for water sorption and dye uptake

A novel polymer/clay composite sorbent based on acrylamide/maleic acid, starch and clay such as kaolin was synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N′