engleski

Competitive sorption of phosphate and marine humic substances on suspended particulate matter

The sorption behavior of dissolved orthophosphate 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 Raska bay, Adriatic sea. Since the phenomena of phosphate fixation are especially important in estaurine waters, when fresh and saline waters undergo mixing in the coastal zone, the influence of salinity was studied. It was found that the following effects could be considered: -reduced phosphate fixation due to favorable sorption of humic substances onto suspended particles, -enhanced sorption induced by increased salinity and concentration of Ca2+ ions which enabled the bridging between sorbed humic acids and phosphate.

marine humic acid ; particulate matter ; phosphate ; sorption

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