The coprecipitation of Cd, Co and Eu from seawater onto ferric hydroxide was studied, using the radioactive tracers 109Cd, 60Co and 152-154Eu, as a function of the pH, the concentration of the collector iron, the concentration of the metal spike and the aging of the internally formed precipitate. For preconcentration purpose, a pH 9 and a 35 ppm iron concentration appeared to be suitable. At pH 8, the natural pH of seawater, the distribution coefficients for Cd, Co and Eu are 104.5, 105 and 107, respectively. |