Some aspects of the interactions between particulate oxides and aquatic humic substances

Abstract

The adsorption of humic substances (HS) by oxides is briefly reviewed, and the interfacial region of an oxide with adsorbed HS qualitatively described. In the light of this information the following are discussed: (a) the effects of adsorbed HS on the colloid stability of oxide particles; (b) the uptake of trace metals by oxides in the presence of HS; (c) transport of HS in natural waters, following their adsorption to and co-sedimentation with iron oxide particles; and (d) photoreduction of natural iron oxide-humic coprecipitates and their role in supplying iron to phytoplankton.