Kinetics, isotherms and thermodynamics of Cu(II) metal ions adsorption: an insight into chitosan and bentonite

Chitosan + bentonite modified composite was synthesized to analyse its removal efficiency for Cu(II) metal ions.FTIR analysis done for chitosan, bentonite and the prepared biocomposite of chitosan + bentonite gave detailed information about the active functional group present on the site of adsorbent.SEM-EDS micrographs reflected the distribution and weight percent of elements in the prepared bio-composite with prominent porosity and roughness but after the adsorption of Cu(II), the porosity and roughness of the adsorbent decreased.Freundlich isotherm best fitted to Cu(II) metal ions indicates that the adsorbent surface is heterogenous.The value of the regression coefficient for the Lagergren kinetic model for the adsorption of Cu(II) metal ions was 1 and hence, it has the highest conformity towards the pseudo-first-order kinetic model.Adsorption thermodynamics revealed that it was a spontaneous and exothermic adsorption.