kappa-Carrageenan beads as new adsorbent to remove crystal violet dye from water: adsorption kinetics and isotherm

K+-Cross-linked kappa-Carrageenan beads were prepared and the dried and wet beads of cross-linked carrageenan were evaluated to remove the cationic crystal violet (CV) dye from water. The kinetics and mechanism of CV adsorption onto both wet and dried carrageenan beads were studied. The effect of contacting time and initial concentration of CV on adsorption was investigated. It was revealed that the rate of dye adsorption and removal efficiency is higher for the wet carrageenan beads. The experimental adsorption data were modeled using pseudo-first-order, pseudo-second-order, and Boyd models. The results showed that the pseudo-second-order adsorption kinetics were predominated for the adsorption of CV onto carrageenan beads. The experimental equilibrated adsorption capacity of carrageenan beads was analyzed using Freundlich and Langmuir isotherm models. The results corroborated that the experimental data followed the Freundlich isotherm the best. No significant change in dye adsorption onto beads was observed by varying the pH of initial dye solution.