AMİDOKSİM FONSİYONEL GRUBU İÇEREN PAMUK KUMAŞLARIN AŞI POLİMERİZASYONU İLE HAZIRLANMASI
In this thesis, amidoxime group containing nonwoven cotton fabrics were prepared by grafting with acrylonitrile (AN) using plasma-induced graft polymerization method for the recovery of uranium ions in trace amounts from seawater. Different parameters such as power applied and plasma treatment time were studied to determine optimum plasma treatment conditions in order to perform graft polymerization. The experiments were carried out by applying three different plasma powers (60, 80 and 100 watts) and three different treatment periods (3, 5 and 10 min) in the plasma process. The optimum plasma treatment conditions for the grafting of acrylonitrile onto the nonwoven cotton fabrics were determined as 0.2 mbar pressure, 100 watts of power and 10 min of treatment time in Ar-plasma. Grafting of AN onto nonwoven cotton fabrics by using plasma-induced graft polymerization were carried out in emulsion solutions at different reaction temperatures (40, 60 and 70°C) and different concentrations (10% (w/w), 30% (w/w), 50% (w/w) and 70% (w/w)) for 24 h to increase the degree of grafting of AN. Homopolymer formation was observed in 50% and 70% (w/w) AN solutions while the grafting formation was not observed in 10% (w / w) AN emulsion solution within 24 hour. The optimum grafting conditions were determined as 30% (w/w) AN concentration, 0.5% Tween 20, 60 °C reaction temperature and 24 hour reaction time. For the preparation of uranyl ion selective adsorbent, the nitrile groups in the AN grafted nonwoven cotton fabric was converted to amidoxime groups by using hydroxylamine. The AO conversion amount was calculated to be 10.48 mmol/g cotton. AO group containing nonwoven cotton fabric was used fort he adsorption of U(VI) from aqueous solutions by studying the effect of pH, adsorption kinetics and initial concentration U (VI). It was found that the adsorption of U (VI) ion reached to equilibrium at 90 minutes and the amount of adsorption from a 250 ppm U (VI) solution was determined to be 530,46 mg U (VI)/g adsorbent at pH 6.00. Desorption of uranyl ions from nonwoven cotton fabrics was performed by using %3 HNO3 and nearly 100% of U (VI) ions were desorbed. Five adsorption desorption cycles were obtained as a result of reusability studies. The adsorption amount was determined as 0,17 mg (VI)/g adsorbent from 10 mL of seawater for 24 hours. The chemical structures, surface morphology and thermal properties of nonwoven cotton fabric, AN grafted, AO group modified and U (VI) adsorbed nonwoven cotton fabrics were characterized by using FTIR, XPS, SEM, EDX and TGA techniques.