Investigation of brilliant green removal by using poly (akrilonitrile-co-N-vinyl pyrrolidone) / zeolite composite of brilliant green removal from aqueous solutions

In this thesis study, adsorption in batch system of the cationic dye brilliant green (BG) is investigated by using the poly(acrylonitrile-co-N-vinyl pyrrolidone)/zeolite (poly(AN-co-VP)/zeolite) composite polymer that was synthesized by in situ free radical polymerization. The effect of the pH, the initial concentration of BG, the amount of adsorbent and the temperature were determined. The highest removal yield (97.60%) was achieved at the initial BG concentration of 25 mg/L, at the adsorbent amount of 0.2 g/50 mL, the pH of 4.5 and at temperature of 40 °C. The structural and thermal properties of composite were determined by FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy), XRD (X-ray diffraction diffractometry), TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) and results of characterization showed that the composite has a homogeneous and three-dimensional structure. Decomposition temperature and glass transition temperature were found to be 410 oC and 152 oC, respectively. The isotherms, kinetics and thermodynamics of adsorption were studied and the results showed that the equilibrium data were better fitted to the Langmuir isotherm model. Kinetic results have shown that one of the speed determination steps of the adsorption process can be defined by pseudo second order kinetics with external mass transfer and internal diffusion. According to thermodynamic properties, the adsorption process was spontaneous and endothermic at the working temperatures. The central composite design involved in the response surface methodology was used to determine the interaction effects onto adsorption of the initial BG concentration, the adsorbent amount, and on the time. From variance analysis (ANOVA), it was found that the model fit of the data is very important (R2 = 0.95). As result, it has been found that the synthesized copolymer is an effective adsorbent for the BG removal of aqueous solutions.