Abstract
Iron may exist in river water as colloidal and suspended particles, generally associated with humic substances, clay and silica. A new Speciation scheme is proposed using sorption on the DEAE-Sephadex A-25 anion-exchanger and the indium-treated Amberlite XAD-2 resin as well as filtration. Several composite particles have been artificially prepared to simulate natural particles and their sorption behavior has been examined. In the river water examined, about half of the dissolved iron species (the fraction which passes a 1-μm filter) was negatively charged humic colloids, most of which contained clay, while the remainder were essentially inorganic colloids, which included negatively charged aggregates of hydrated iron(III) oxide and clay (or silica) as well as positively charged hydrated iron(III) oxide. The correlation of copper with iron is also discussed.
