Removal of natural organic material by a magnetic ion exchange resin

Abstract

The aim of this research was to elucidate the interactions among dissolved organic carbon (DOC), inorganic anions and a magnetic ion exchange (MIEX) resin. Model waters containing well characterised natural organic matter (NOM) extracts in addition to DOC-free model waters containing sulphate and bicarbonate were used in all experiments. The NOM extracts used in this work included two reference fulvic acids supplied by the International Humic Substances Society (IHSS): Suwannee River Fulvic Acid (SRFA) and Pony Lake Fulvic Acid (PLFA). These reference fulvic acids possess unique chemical characteristics that are representative of their distinct end-member environments. The charge density of the NOM extracts, obtained by potentiometric titration, was used to perform charge balance analyses for ion exchange reactions involving DOC, sulphate, bicarbonate and chloride. For SRFA, the results clearly show the stoichiometric exchange of DOC and bicarbonate for chloride. This work provides an improved understanding of the interactions between NOM, MIEX resin and the background solution matrix, and should result in more effective applications of ion exchange treatment for the removal of DOC during drinking water treatment.