Tracking and Recovery of Metal Desorption from Organized Films of Polyguanamine Derivatives having Cyclic Moieties

Abstract

AbstractMetal desorption behavior of polyguanamine derivatives having cyclic moieties (c‐PGs), with metal‐scavenging abilities, organized into molecular films was investigated, and a recovery technique was realized. Cadmium (a toxic metal), palladium (a precious metal), and neodymium (a rare earth metal) were studied, along with sodium (a cationic metal). A monolayer of c‐PGs forming on an aqueous metal solution surface effectively scavenges cations from the subphase owing to the relative basicity of the cyclic moiety. X‐ray photoelectron spectroscopy revealed that cadmium and palladium (both divalent cations) were desorbed by simple 30–60 min ultrasonication of their Langmuir–Blodgett multilayers. Conversely, the desorption of neodymium, a trivalent cation, was very slow. Sodium, a monovalent cation, was difficult to collect. Its valence and monolayer condensation on the aqueous sodium buffer were remarkable, indicating that coordinated sodium ions escape during the monolayer condensation.