Enhanced adsorption of aqueous copper(II) ions using dedoped poly-N-phenylglycine nanofibers (original) (raw)

We report on adsorption of aqueous Cu 2+ using poly N-phenylglycine (PPG) nanofibers (NFs) prepared by radical polymerization process. The carboxylic acid groups of pristine PPG NFs were deprotonated to form carboxylate groups, resulting in hydrogen-dedoped PPG NFs. The Cu 2+-adsorption capability of PPG NFs was markedly increased after the deprotonation, presumably due to high ionic attraction feature of carboxylate in dedoped PPG. We further investigated the pH-dependent adsorption capability of PPG NFs and found much higher Cu 2+ adsorption capacity under high pH conditions, owing to spontaneous deprotonation by the basic solution. X-ray photoemission confirmed the adsorption of Cu 2+ on PPG NFs, and Fourier transform infrared spectroscopic analyses confirmed the reduced density of carboxylic acid by deprotonation. The ability of pristine and dedoped PPG NFs to capture aqueous Cu 2+ is discussed. Our method to improve the adsorption capability using surface modification could be readily applied to many other polymeric or organic nanostructures for metal removal.