EFFECT OF THE PRESENCE OF SOME ANIONS ON THE CRYSTAL GROWTH OF CALCITE IN AN ARTIFICIAL SEAWATER

EFFECT OF THE PRESENCE OF SOME ANIONS ON THE
CRYSTAL GROWTH OF CALCITE IN AN ARTIFICIAL
SEAWATER
SAMIA K HAMDONA
National Institute of Oceanography & Fisheries
[email protected].
Key Words: Calcite, Crystal Growth, Other Anions, Adsorption, Artificial Seawater.
ABSTRACT
Effect of the presence of inorganic phosphate, sulfate, fluoride and urate on crystal
growth of the precipitated calcite in an artificial seawater at 25°C, pH=8.5 and salinity
=350
/00 has been studied. The crystal growth of calcite crystals is markedly inhibited by the
presence of each of these additives except sulfate. The degree of inhibition increases with
the successive addition of anions and with decrease of saturations. The effect of the studied
inhibitors (phosphate, fluoride and urate ions) have been attributed to the blocked active
sites on the crystal surfaces by adsorption of these anions. The reduction in precipitation
rates can be interpreted in terms of Langmuir – type adsorption isotherm.