Adsorption properties of Cd(II)-imprinted chitosan resin

A Cd(II)-imprinted chitosan resin (Cd-ICR) was prepared for adsorption of Cd(II) from aqueous solutions. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity and reusability as well as its application in the removal of Cd(II) from oyster hydrolysate. The results indicated that the maximum adsorption capacity of Cd-ICR was 0.795 mmol/g in sole Cd(II) solution at pH 5.0, 45 °C with equilibrium time 10 h. The selectivity coefficient of Cd(II) and other metal cations on Cd-ICR indicated an overall preference for Cd(II), which was much higher than that of non-imprinted chitosan resin. Cd-ICR could be reused for ten times with about 27% regeneration loss. FTIR spectra demonstrated that Cd(II) in Cd-ICR occurred on amino and secondary hydroxyl groups. The removal ratio of Cd(II) from oyster hydrolysate was 73.6%, while that of Ca(II) and Zn(II) were 6.2 and 9.9%, respectively. This suggests that Cd-ICR is a very promising adsorbent for selective removal of Cd(II) from aqueous solutions.