Bengi Özkahraman

Study on adsorption, regeneration, and reuse of crosslinked chitosan graft copolymers for Cu(II) ion removal from aqueous solutions

AbstractThis study deals with the adsorption, regeneration, and reuse of chitosan-graft-itaconic acid and chitosan-graft-crotonic acid beads for Cu(II) ion removal from aqueous solutions. For this aim, adsorption capacities, adsorption kinetics, and adsorption isotherms of these crosslinked chitosan-graft-copolymeric beads were investigated in detail. The maximum adsorption capacities of chitosan-graft-itaconic acid and chitosan-graft-crotonic acid beads were found to be 0.31 and 0.25 mmol/g, respectively. In addition, it was found that the pseudo-second-order kinetic model is more suitable than pseudo-first-order model for the adsorption of Cu(II) ions onto the beads according to adsorption kinetics data. Adsorption isotherm data were evaluated using Freundlich, Langmuir, Brauner–Emmet–Teller, Dubinin–Radushkevich and Temkin isotherm models. The results revealed that the adsorption of Cu(II) ions onto the beads fits very well Freundlich isotherm model. Then, the beads were regenerated with an acid soluti...

Sodyum Akrilat Esaslı Hidrojel ve Kriyojellerin Şişme, Adsorpsiyon ve Mekanik Özelliklerinin İncelenmesi

Bu calismada, sodyum akrilat esasli hidrojel ve kriyojellerin sisme davranislari (sisme kapasitesi, denge sisme degeri ve sisme kinetigi), boyar madde (metilen mavisi) adsorpsiyonu ve mekanik ozellikleri karsilastirmali olarak incelenmistir. Kinetik paramatreler, dogrusal ve dogrusal olmayan metotlar kullanilarak belirlenmistir. Buna ek olarak, kriyojel ve hidrojel yapilarin yuzey morfolojileri, taramali elektron mikroskobu (SEM) kullanilarak karakterize edilmistir. Analizlerden elde edilen tum sonuclar karsilastirmali olarak degerlendirilmistir. In this study, swelling behavior (swelling capacity, equilibrium swelling ratio and swelling kinetics), basic dye (methylene blue) adsorption and mechanical properties of sodium acrylate based hydrogel and cryogels were comparatively investigated. Kinetic parameters were determined using linear and non-linear methods. In addition, the surface morphologies of cryogel and hydrogel structures were characterized using by Scanning Electron Microscopy (SEM). All results obtained from analyses were comparatively evaluated. Anahtar kelimeler: Hidrojel, Kriyojel, Adsorpsiyon, Sodyum akrilat, Dogrusal ve dogrusal olmayan analiz yontemleri.