Pınar Akkaş Kavaklı

Adsorption Efficiency of a New Adsorbent Towards Uranium and Vanadium Ions at Low Concentrations

Abstract A new type of fibrous adsorbent with excess amidoxime groups was synthesized by radiation-induced graft polymerization. Glycidyl methacrylate (GMA) was first radiation‐grafted on polyethylene‐coated polypropylene nonwoven fabrics and chemically modified with 3,3′-iminodipropionitrile [NH (–CH2–CH2–CN)2] (IDPN), which was further reacted with hydroxylamine to obtain graft chains containing two amidoxime groups per graft repeating units. The adsorption properties of this new adsorbent for uranium (U), vanadium (V), lead (Pb), copper (Cu), and cobalt (Co) ions at low concentrations (3.3–1000 ppb) were investigated by a batch process. The adsorbent showed enhanced adsorption capacity for uranium and vanadium ions. In adsorption studies from a mixture of metal ions in aqueous solutions, the adsorbent showed selectivity for metal ions in the following order: V > U ≫ Cu ≥ Pb ≫ Co. The selectivity of the adsorbent was assessed by determining the distribution coefficient D, of the metal ions studied. The U and V ions were shown to be up to six times more selectively adsorbed onto the new adsorbent than the other metal ions.

Investigation of Heavy Metal Ion Adsorption Characteristics of Poly(N,N Dimethylamino Ethylmethacrylate) Hydrogels

Abstract In this study, Poly(N,N dimethyl‐amino ethylmethacrylate) (Poly(DMAEMA)) hydrogels with varying compositions were prepared in the form of rods by irradiating ternary mixtures of N,N‐dimethylamino ethylmethacrylate/ethyleneglycoldimethacrylate/water with gamma rays at ambient temperature. Swelling studies of poly (DMAEMA) hydrogels were performed at different pH values and maximum swelling values reached at pH 2. The adsorption characteristics of Pb(II), Cd(II), Ni(II), Zn(II), Cu(II), and Co(II) ions to poly(N,N dimethylamino ethylmethacrylate) hydrogels were investigated by a batch process. The order of affinity based on amount of metal ion uptake was found as follows: Cu(II)>Zn(II)≅Co(II)>Pb(II) >> Ni(II)>Cd(II). In the adsorption studies of Cu(II), Zn(II), Co(II), Pb(II), Ni(II), and Cd(II) ions the Langmuir type adsorption isotherms were observed for all gel systems.

Preparation and characterization of ethylenediamine modified glycidyl methacrylate-grafted nonwoven cotton fabric adsorbent

Abstract In this study, plasma-initiated graft polymerization of glycidyl methacrylate (GMA) onto nonwoven cotton fabric (NCF) and its modification with ethylenediamine (EDA) was performed. To determine the optimum conditions for plasma treatment, a comprehensive analysis of different parameters such as plasma power, applied pressure, applied plasma gas, and exposure time were conducted using both air- and Ar-plasma. The concentration of radicals generated on the NCF surface after plasma treatment was examined using ESR spectroscopy. The effects of plasma pretreatment conditions, namely GMA concentration, grafting temperature, and grafting time were investigated. Plasma treated NCF has been grafted with GMA (GMA-g-NCF) was functionalized with ethylenediamine (EDA-GMA-g-NCF) to develop an efficient arsenic adsorbent. NCF, GMA-g-NCF and EDA-GMA-g-NCF samples were characterized by using FTIR, SEM, EDX, XPS, elemental analysis, TGA, and contact angle.

In vitro shear bond strength between fluorinated zirconia ceramic and resin cements

PURPOSE The purpose of this study was to evaluate the efficiency of a gas-phase fluorination method under different fluorination periods through using two resin cements. MATERIALS AND METHODS 84 zirconia specimens in dimensions of 5 mm × 5 mm × 2 mm were prepared and surface treated with 50 µm aluminum oxide particles or gas phase fluorination for 2 min, 5 min, or 10 min. One specimen in each group was surface analyzed under scanning electron microscope. The remaining specimens were bonded to composite cylinders in dimensions of 2 mm diameter and 3 mm high with Panavia SA Plus or Variolink N. Then, the specimens were stored in 37℃ distilled water for 24 hours and shear bond strength test was applied at a speed of 1 mm/min. RESULTS The highest shear bond strength values were observed in the samples fluorinated for 5 minutes and cemented with Panavia SA Plus. Variolink N did not elicit any statistical differences between surface treatments. Panavia SA Plus resin cement and Variolink N resin cements featured statistically significant difference in shear bond strength values only in the case of 5 minutes of fluorination treatment. CONCLUSION According to the results of this study, application of 5 minutes of fluorination with 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP) containing Panavia SA Plus resin cement increased the resin bond strength of zirconia. Fluorination of the zirconia surface using conventional resin cement, Variolink N, did not lead to an increase in bond strength.