Arsenik Ve Selenyum İyonlarının Adsorpsiyonunda Kullanılan Fonksiyonel Polimerik Adsorbent Geliştirilmesi
Özet
In this thesis, grafted polyethylene coated polypropylene (PE/PP) nonwoven fabrics containing amine groups for the removal of arsenic and selenium ions from environmental waters and industrial waste water are prepared by graft polymerization method with grafting 4- (chloromethyl) styrene (CMS) by using the 60Co gamma-ray source. Non-woven fabrics were prepared by irradiating with 10 kGy of total irradiation dose, using CMS solutions prepared by organic solvent (toluene) and emulsion (water and surfactant tween20 ) at different concentrations to accomplish graft polymerization.
Grafting studies were carried out in two methods. These methods are grafting by simultaneous irradiation and grafting by pre-irradiation. As a result of these studies, the highest and steady grafting were obtained with grafting by simultaneous irradiation and toluene as solvent. At grafting by simultaneous irradiation in which samples prepared by emulsion, excessive grafting was observed and the fabrics partially lost their elasticity. In grafting by pre-irradiation studies, when toluene is used as solvent, the percentage of grafting is very low. When working with emulsion using the same method, steady grafting could not be obtained while some homopolymer residues were observed on some sample surfaces in fabrics.
For the preparation of a selective adsorbent for arsenic and selenium ions, the chlorine groups in the CMS grafted PE/PP nonwoven fabric structure obtained under optimum conditions were modified with amine groups with 3- (dimethylamino) -1-propylamine. The amount of the resulting amine group was calculated to be 2.75 mmol / g of grafted fabric.
The effect of pH, adsorption kinetics and initial concentration on the adsorption of As (V) and Se(VI) ions on modified PE/PP nonwoven fabric adsorbent containing amine group was studied. It has been found that the optimum pH is 4,00 for both elements. Adsorption of As (V) ion reaches the balance at 360 minutes in optimum pH 4,00 and that the adsorbed amount of 250 ppm As (V) solution is 110,52 mg As (V) / g polymer. Desorption of arsenic ions adsorbed PE/PP nonwoven fabric adsorbent was performed with 3% HNO3 and approx. 100% of As(V) ions were desorbed. As a result of reusability studies, it has been observed that the adsorption of As (V) ions is maintained throughout the five adsorption desorption cycles. Adsorption of Se(VI) ion also reaches the balance at 360 minutes in optimum pH 4,00 and that the adsorbed amount of 250 ppm Se(VI) solution is 107,68 mg Se(VI) / g polymer.
Chemical structures, surface morphology and thermal properties of PE/PP nonwoven fabric, CMS grafted, amine group modified, arsenic and selenium ions adsorbed PE/PP nonwoven fabrics were characterized using FTIR, XPS, SEM, EDX, Elemental analysis and TGA techniques.
