engleski

Competitive Sorption of Phosphate and Marine Humic Substances on Suspended Particulate Matter

The sorption behaviour of dissolved othophosphate in the presence of background organics has been evaluated by studying the sorption on suspended particles (sand, calcite, bentonite and iron oxide). Humic and fulvic acids, that are the most significant component of organic substances in aquatic systems, were used as competitive solutes. Marine humic substances were isolated from the surface part of the sediment collected in Raška bay, adriatic sea. Since the phenomena of phosphate fixation are especially important in estuarine waters, when fresh and saline waters undergo mixing in the coastal zone, the influence salinity was studied. It was found that the following effects could be considered: -reduce phosphate fixation due to favorable sorption of humic substances onto suspended particles, -enhance sorption induced by increased salinity and concentration of Ca(2+)-ions which enable the bridging between sorbed humic acids and phosphate.

marine humic acids; particulate matter; phosphate; sorption

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