Innovative peptide-functionalized microbeads: A highly selective biosorbent for scandium extraction

Scandium recovery from tailings and related leachate offers both economic and environmental benefits, but faces technical challenges due to substantial competing impurities. This study designed a novel metal-binding peptide with high affinity and selectivity towards scandium (ScBP). A comprehensive characterization revealed that oxygen atoms from aspartic acid, glutamic acid and tyrosine residue coordinated with scandium. To facilitate efficient scandium recovery from solutions, the water-soluble ScBP was immobilized on magnetic beads through thiol-maleimide click chemistry. The resulting Mag@ScBP microbeads exhibited a maximum scandium adsorption capacity of 124.92 mg/g and high selectivity for scandium at lower pH. Notably, the microbeads were tested with two types of simulated industrial wastewater generated during the processing of the Bayan Obo mine, achieving over 96 % scandium recovery efficiency for both solutions. Moreover, the purity of the recovered scandium increased by 900 to 1200-fold following a straightforward adsorption–desorption process, highlighting their excellent potential for scandium recovery in complex industrial contexts.