Kinetic and equilibrium studies on the removal of Congo red from aqueous solution by biosorption on crosslinked chitosan- ECH nanoparticles

The nanoparticles of templated crosslinked chitosan, was prepared through using ECH as a crosslinker. The nanoparticles exhibited significantly higher adsorption capacities from the congo red dye than other adsorbent formed without a crosslinker. The adsorption of the dyes on the nanoparticles was affected by the initial pH, dye concentration, and temperature. The results were in accordance with the second-order adsorption models. The E a values of the dyes calculated using the Arrhenius’s equation revealed that the adsorption process may be due to the dual nature of the process, physisorption and chemisorption, and that adsorption was predominant in the chemisorption process. The adsorption processes in the nanoparticles were spontaneous and exothermic.