Ali Delibaş

Indirect speciation of Cr(III) and Cr(VI) in water samples by selective separation and preconcentration on a newly synthesized chelating resin.

A new solid phase extraction method for the speciation, separation and preconcentration of Cr(III) and Cr(VI) was developed. As solid phase material, a new chelating resin, poly N-(4-bromophenyl)-2-methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene was synthesized. Cr(III) was separated from Cr(VI) and preconcentrated by using a column containing chelating resin. Total chromium was determined after the reduction of Cr(VI) to Cr(III) by hydroxylamine hydrochloride as a reducing agent. Then Cr(VI) was calculated by substracting Cr(III) concentration from the total chromium concentration. The parameters such as the effect of pH, eluent type, volume and concentration, flow rate of sample solution, sample volume and effect of interfering ions for the preconcentration of Cr(III) were investigated. The optimum pH was found to be 2. Eluent for quantitative elution was 10 mL of 1 mol L(-1) HCl. The preconcentration factor of the method was 100. At the optimum conditions determined experimentally, the recovery for Cr(III) was found to be 95 +/- 3%. The limit of detection (3s/b) of the method was 1.58 microg L(-1). In order to determine the adsorption behaviour of chelating resin, the adsorption isotherm of Cr(III) was studied. Adsorption capacity and binding equilibrium constant were calculated to be 21.8 mg g(-1) and 1.32 x 10(-2) L mg(-1), respectively. The method was validated by analysing certified reference material (TMDA-54.4 a trace element fortified calibration standard). The proposed method was applied to the determination and speciation of chromium in tap water, lake water, spring water and wastewater samples with satisfactory results.

Synthesis of a novel chelating resin and its use for selective separation and preconcentration of some trace metals in water samples

A new chelating resin, poly[N-(4-bromophenyl)-2-methacrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid-co-divinylbenzene], was synthesized and characterized. The resin was used for selective separation, preconcentration and determination of Cu(II), Ni(II), Co(II), Cd(II), Pb(II), Mn(II) and Fe(III) ions in water samples by flame atomic absorption spectrometry. Effects of pH, concentration and volume of elution solution, sample flow rate, sample volume and interfering ions (Na(+), K(+), Ca(2+), Mg(2+), Fe(3+), Mn(2+), Al(3+), Zn(2+), Pb(2+), Cu(2+), Ni(2+), Cd(2+), Cl(-) and SO(4)(2-)) on the recovery of the analytes were investigated. The sorption capacity of the resin was 25.6, 19.8, 32.1, 41.3, 38.9, 13.9 and 18.3 mg g(-1) for Cu(II), Ni(II), Co(II), Cd(II), Pb(II), Mn(II) and Fe(III), respectively. A high preconcentration factor, 100, and low relative standard deviation, <or=2.5% (n=7) values were obtained. The detection limits (microg L(-1)) were 0.57 for Cu(II), 0.37 for Ni(II), 0.24 for Co(II), 0.09 for Cd(II), 1.6 for Pb(II), 0.19 for Mn(II) and 0.72 for Fe(III). The method was validated by analysing fortified lake water (TMDA-54.4, a trace element fortified calibration standard) and spiked water samples. The method was applied to the determination of the analytes in tap and lake water samples.

Novel Copolymers of N‐(4‐Bromophenyl)‐2‐Methacrylamide with 2‐Acrylamido‐2‐Methyl‐1‐Propanesulfonic Acid

The new acrylamide monomer, N‐(4‐Bromophenyl)‐2‐methacrylamide (BrPMAAm) has been synthesized by reacting 4‐Bromoaniline with methacryloyl chloride in the presence of triethylamine(NR3) at 0–5°C. The radical‐initiated copolymerization of (BrPMAAm), with 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) has been carried out in dimethylformamide (DMF) solution at 70±1°C using 2,2′‐azobisisobutyronitrile (AIBN) as an initiator with different monomer‐to‐monomer ratios in the feed. The copolymers were characterized by FTIR, 1H‐ and 13C‐NMR spectroscopy. The copolymer composition was evaluated by nitrogen content (N for AMPS‐units) in polymers led to the determination of reactivity ratios. The monomer reactivity ratios for BrPMAAm (M1)‐AMPS (M2) pair were computed using the Fineman‐Ross (F‐R), Kelen‐Tüdös (KT) and Extended Kelen‐Tüdös (EKT) methods. These parameters were also estimated using a non‐linear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The mean sequence lengths determination indicated that the copolymer was statistically in nature. By TGA and DSC analyses, the thermal properties of the polymers have been studied. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.

Novel Copolymers of 4-Chloronaphthyl Methacrylate with Acrylonitrile: Determination of Monomer Reactivity Ratios and Antimicrobial Activity

Methacrylate based monomer, 4-chloronaphthyl methacrylate (4-CNMA) was synthesized by reacting 4-chloro naphthol with methacryloyl chloride in the presence of triethylamine (NR3) at 0–5°C. The free-radical initiated copolymerization of (4-CNMA), with acrylonitrile (AN) was carried out in 1,4-dioxane-dimethyl sulfoxide mixture (8:2) solution at 70 ± 1°C using 2,2′-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomer 4-CNMA, poly(4-CNMA) and copolymers were characterized by FT-IR and 1H-and 13C-NMR spectral studies. The copolymer composition obtained by elemental analysis led to the determination of reactivity ratios employing Fineman-Ross (F-R), Kelen-Tüdös (KT) and Extended Kelen-Tüdös (EKT) linearization methods. These parameters were also estimated using a non-linear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The solubility of the polymers was tested in various polar and non-polar solvents. Gel permeation chromatography was employed to determine the molecular weights (Mw and Mn) and polydispersity index of polymers. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with increase in the mole fraction of 4-CNMA in the copolymers. The prepared homo and copolymers were tested for their antimicrobial activity against bacteria, fungi and yeast.

COPOLYMERS OF 2-ACRYLAMIDO-2-METHYL-1-PROPANESULFONIC ACID/MALEIC ACID: SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY

2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and maleic acid (MA) copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide (Bz2O2) as an initiator at 70°C. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis (content of N for AMPS-units). Monomer reactivity ratios for AMPS (M1)-MA (M2) pair were determined by the application of conventional linearization methods such as Fineman-Ross (F-R), Kelen-Tudos (KT) and Extended Kelen-Tudos (EKT) and a nonlinear error invariable model method using a computer program RREVM. The characterizations were done by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) thermal gravimetry analysis (TGA), and and X-ray diffraction. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.