Co (II) - Imprinted Polymer Beads for Cationic Dye Removal from Water

An adsorbent (Co(II)-imprinted polymer beads) was prepared using PVA/SA. The adsorbent was used to remove cationic dye (crystal violet) efficiently. Batch adsorption studies were performed in respect to variation in solution pH, dosage, initial dye concentration, contact time, temperature and binary system to check the effectiveness of the prepared beads in adsorbing CV. The adsorption kinetics, thermodynamics and isotherm were evaluated based on the parameters listed above. Structural characterization was done on the prepared and adsorbed beads using FTIR. Maximum dye adsorption of 94 % was attained at pH 9, using 0.15 g adsorbent dose, at 90 min of contact time, with an initial CV concentration of 20 mg/L. Also the removal of CV is almost not affected by the presence of other cationic pollutants (methylene blue dye) in a binary system. The FTIR characterization revealed that CV was adsorbed onto the prepared adsorbent successfully and that the carboxyl group of the PVA/SA took part in the reaction. The kinetic studies indicates that the adsorption process aligned with the pseudo second-order kinetics. The thermodynamics parameters show that the adsorption process of CV onto Co-imprinted beads were exothermic, spontaneous and tends towards orderliness at low temperatures between 298 and 308 K. The ∆G value indicates a Physisorption process. The isotherm studies indicates that the adsorption mechanism is best explained by the Langmuir isotherm. The study has demonstrated that the prepared adsorbent (Co(II)-imprinted polymer beads) has a potential in adsorbing crystal violet dye from aqueous solutions. Keywords: Co(II)-imprinted polymer beads; Crystal Violet dye; Adsorption studies; Adsorption kinetics; Isotherm studies