Adsorption of Cu(II) ions in aqueous solution using chitosan beads, chitosan–GLA beads and chitosan–alginate beads

The use of chitosan beads, chitosan–GLA 1:1, 2:1 ratio beads, and chitosan–alginate beads for the removal of Cu(II) ions from aqueous solution at different initial pH, agitation periods, adsorbent dosage, and initial concentrations has been investigated. The equilibrium adsorption data were described by the non-linear Langmuir, Freundlich and Sips isotherms. Chitosan beads, chitosan–GLA 1:1 and 2:1 ratio beads agreed well with the non-linear Freundlich isotherm, though it gave an adsorption capacity of 64.62 mg/g, 31.20 mg/g and 19.51 mg/g, respectively, based on the non-linear Langmuir isotherm. Meanwhile, chitosan–alginate beads showed a better fit to the non-linear Langmuir isotherm giving an adsorption capacity of 67.66 mg/g. Based on the Sips isotherm, chitosan beads, chitosan–GLA 1:1 and 2:1 ratio beads are heterogeneous adsorbents, meanwhile chitosan–alginate beads is a homogeneous adsorbent. The pseudo-first and pseudo-second orders and intraparticle diffusion equation were used to evaluate the kinetic data and the constants are determined.