Adsorptive Recovery of Palladium(II) and Platinum(IV) on the Chemically Modified-Microalgal Residue

A biomass waste of microalgae was chemically modified by immobilizing the functional group of polyethyleneimine to prepare a new type of adsorbent. The adsorption test revealed that this adsorbent exhibited remarkably high selectivity for Pd(II) and Pt(IV) over base metal ions in HCl solution. From the adsorption isotherm, its maximum adsorption capacity for Pd(II) and Pt(IV) was evaluated as 2.0 and 0.8 mmol/g, respectively. This adsorbent also exhibited high affinity and selectivity for Pd(II) and Pt(IV) even in the presence of high concentrations of base metals in actual leach liquor.