Glutaraldehyde-crosslinked chitosan beads for sorptive separation of Au(III) and Pd(II): Opening a way to design reduction-coupled selectivity-tunable sorbents for separation of precious metals

► GA-CS shows selective sorption of Au(III) in Au(III)-Pd(II) mixture. ► Increase of GA content leads to more selectivity toward Au(III) in bi-metal solution. ► A multi-step desorption process enables selective recovery of Pd and Au from sorbents.