TRACE CONTAMINANT SORPTION THROUGH POLYMERIC LIGAND-EXCHANGE

Various industrially and environmentally important trace contaminants in water and wastewater bodies are anionic ligands, namely, phosphate, selenite, arsenate, sulfide, phthalate, oxalate, ethylenediaminetetra acetate, cyanide, and a ho st of organic derivatives. Traditional sorb ents such as activated carbons, ion exchangers, iron oxyhydroxides, et c. are not effective for selective sorption of the foregoing contamina nts. This study reports the results and underlying sorption mechanisms of a tailored polymeric ligand exchanger (PLE) which shows very high affinities toward phosphate, selenite, and oxalate. The polymeric liga nd exchanger used in the study is essentially a copper(II)-loaded spec ialty chelating polymer, and its preference toward anionic ligands is attributed to concurrent electrostatic and Lewis acid-base type intera ctions. PLE is also amenable to efficient regeneration with brine, and more than 90% phosphate was recovered in less than 10 bed volumes.