LAUSR

Abstract Functionalized nanoparticles (NPs) are critical to a wide-ranging of applications. The more versatile use of the NPs hinges on the capability to readily modify them to perform different functions. For example functionalized polymeric nanomaterials bearing ligands can be employed in metal ion extraction and recovery. However, obtaining ion-imprinted particles via ligand copolymerization can be difficult to scale-up. We therefore present an alternative method to obtain ligand-carrying polymeric nanoparticles (LC-NPs) for metal ion absorption. Branched polyethyleneimine (b-PEI) was used to modify the negatively charged surfactant-free polystyrene (PS) NPs obtained via surfactant-free emulsion polymerization by employing “surfmers”. The obtained PEI-PS NPs were further cross-linked with phthaldialdehyde to form cross-linked PEI-PS (CPEI-PS). Both PEI-PS and CPEI-PS were capable of absorbing chromium, nickel, cobalt and copper ions, as evident in the color change upon absorption. Furthermore, the ion absorption capacity of both types of particles was comparable, but with a greater selectivity toward copper ions. The selectivity towards copper ions of CPEI-PS increased with the degree of dialdehyde cross-linking. Repeated absorption-desorption cycles showed no loss in the absorption capacity of CPEI-PS as compared to the non-crosslinked PEI-PS. Finally, both were further reacted with two different aldehydes, which ascertained that the primary amine groups were present for further reaction with aldehydes and thereby enabling further functionalization of these particles.