Preparation of a novel polymer composite doped with EuCl₃ and application for removal of dye

In this thesis, the performance of the 4-vinylpyridine-co-acrylamide doped EuCl3 (poly(4-VP-co-AAm)/EuCl3) hydrogel synthesized in the laboratory by free radical in-situ polymerization method in removing naphthol green B from wastewater was investigated. The properties of the adsorbent have been described by various techniques such as Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The dependence of naphthol green B adsorption efficiency on variables such as pH, amount of adsorbent, initial naphthol green B dye concentration, temperature and contact time were investigated in batch system. The highest removal efficiency 30 mg/L initial naphthol green B concentration, 0.05 g/100 mL poly(4-VP-coAAm)/EuCl3 dosage, pH=5.42 and at 25 °C, was obtained as 98.40%. Experimental equilibrium data were in better agreement with the Langmuir isotherm model. The kinetic results showed that the adsorption process can be described by pseudo-second-order kinetics with internal diffusion as one of the rate-determining steps. The adsorption process was found to be exothermic and spontaneous. In order to determine the interaction effects of the selected parameters on the adsorption process and to optimize the adsorption capacity of the process, the central composite design (CCD) in the response surface methodology (RSM) was used. Optimum conditions were found to be 110 mg/L naphthol green B concentration, 0.05 g/100 mL poly(4-VP-co-AAM)/EuCl3 dosage and 165.81 min contact time. The adsorption capacity under these conditions was 206.46 mg/g. Experimental results showed that naphthol green B dye can be successfully removed from wastewaters using poly(4-VP-co-AAm)/EuCl3 hydrogel as adsorbent. Key words: Adsorption, naphthol green B, poly(4-VP-co-AAM)/EuCl3 hydrogel, response surface methodology