Adsorption and Determination of Pd(II) and Pt(IV) onto 3′-Nitro-4-amino Azobenzene Modified Chitosan

3′-Nitro-4-amino azobenzene modified chitosan has been prepared and characterized by FT-IR. The adsorption data have been investigated including the effects of pH, initial concentration, and contact time by batch method. The adsorption of Pd(II) and Pt(IV) was best in the pH range of 4.0–6.0 for Pd(II) and at pH 3.0 for Pt(IV), where the maximum mass adsorption were (29.33 and 43.10) mg·g–1, respectively. The adsorption isotherms obeyed the Langmuir equation for the adsorption of Pd(II) and Pt(IV). The adsorption kinetic data were fitted with a pseudosecond-order model and an intraparticle diffusion model. The results indicated that the adsorption of Pd(II) and Pt(IV) followed a pseudosecond-order model. The adsorbent shows high affinity for Pd(II) and Pt(IV) in binary systems containing each noble metal ion and other base metal ions. The optimal desorption reagent was 0.20 mol·L–1 thiourea + 0.50 mol·L–1 HCl solution for both Pd(II) and Pt(IV). The method was successfully applied for the determination an...