ADSORTION OF PHARMACEUTICAL POLLUTION TO TiO2 NANO-PARTICLES AND COMPOSİTES- FARMASÖTİK KİRLİLİKLERİN TiO2 NANOTANE ve KOMPOZİTLERİNE ADSORPSİYONU
Project no. 713 · Status: Kapanmış · 2016
Summary
In this study, TiO2 nanoparticles (T95) and TiO2/SiO2 composites (TS95) were synthesized by thermal hydrolysis method. The thermal hydrolysis process was performed at constant temperature, reaction time and stirring rate under reflux. In these studies silica (SiO2) obtained from rice husk ash of Edirne's Ipsala region was used as support material. Adsorption behavior of acetylsalicylic acids (ASA), considered as a model drug, in aqueous medium were investigated. It was aimed to increase the adsorption capacities of T95, TS95 and SiO2 nano particle and composites by adding an cationic surfactant (Hexadecyltrimethyl ammonium bromide (CTAB)) at a concetration of 1x10-4 M to the aqueous solution. The characterization studies by using different methods (Brunauer-Emmett-Teller (BET), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), zeta potential measurement, Fourier-transform infrared spectroscopy (FT-IR) and metal analysis (AAS) were also carried out to identify titanium dioxide composites synthesized and their adsorption behavior. The effects of pH, temperature and adsorption time were investigated on the adsorption of acetylsalicylic acids in aqueous medium onto titanium dioxide composites. The adsorption capacity of (ASA) adsorbed titanium dioxide composites produced were determined by adsorption kinetic and equilibrium studies. Pseudo-first-order, (PFO) pseudo-second-order (PSO) and Elovich kinetic and Weber Morris intraparticle diffusion models (WM) and Langmuir, Freundlich, Temkin and Dubinin-Radushkevic isotherm models were applied to the experimental data to elucidate adsorption kinetics and adsorption equilibrium, respectively. Thermodynamic parameters such as the changes in standard Gibbs free energy, enthalpy and entropy were also determined for the adsorption process. The effects of different amount of adsorbent (0.1-3.0 g Ads. L-1) adsorbed ASA concentrations (3.5-5.5 mg ASA L-1), the effect of temperature and pH on the amount of adsorbed ASA were examined. ASA concentrations were measured by HPLC spectrophotometer. It was seen that adsorption equilibrium time was found to be 24 hour for all adsorbent and ASA concentrations It was seen that the adsorption equilibrium data were fitted to Langmuir and Temkin isotherms for T95 and SiO2 adsorbents whereas it was fitted to Freundlich isotherm for TS95 adsorbent. Therefore; monolayer adsorption of ASA was occured on particles and composites. It was observed that the addition of CTAB on the aqueous solution increases the amount of ASA adsorbed on T95, TS95 and SiO2 adsorbents. Adsorption kinetics of ASA at several temperatures ans pH values for all type adsorbents was also explained by intra particle diffusion (WM) and PSO adsorption kinetic models. Thermodynamic parameters calculated for all adsorbents indicated the spontaneity of the ASA adsorption process and the increase in spontaneity of the formation of ASA adsorption were observed inturn as SiO2, TS95 ve T95.