PREPARATION AND PHYSICOCHEMICAL EVALUATION OF BIODEGRADABLE MAGNETIC K-CARRAGEENAN BEADS AND APPLICATION FOR CHROMIUM IONS PRE-CONCENTRATION

This study aims to examine the ability of magnetic K-carrageenan beads as an adsorbent in solid phase extraction towards chromium ions from aqueous solution. In this study. K-carrageenan magnetic gel-beads were obtained via interphase technique. The heads were kept in 0.3 Ni KCl to maintain gel strength. Physicochemical of the resulting materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). and magnetometer. FTIR results have confirmed the presence of functional groups such as sulphate esters groups. The diameter of carrageenan heads was about <764 pm where SEM micrographs showed the spherical formed shape of carrageenan beads and a rough surface with pores. The saturation magnetization value, M-c, of carrageenan beads in this study was 18.78 EMU/g. The magnetic function of carrageenan beads is to facilitate bead collection and to get the Cr6+ ion that adsorbed onto the beads. The adsorption of chromium ions by magnetic carrageenan heads are through an ion exchange mechanism and formation of metal-ligand complex. Optimal timing for adsorption of chromium ions was at 60th minute. The optimal operation conditions can be achieved on pH value similar to 1 and concentration of 100 ppm. Langmuir adsorption isotherm curve for Cr6+ is similar to Langmuir adsorption isotherm types III (unfavorable).