Cobalt(II) adsorption on haematite at room temperature

Abstract The interactions of Co 2+ with haematite are investigated as a function of the solution pH by means of acid-base titrations and direct adsorption measurements. Adsorption determinations show that Co 2+ is adsorbed on haematite to increasing extents with increasing solution pH. The desorption of Co 2+ from haematite is also found to be a function of pH as Co 2+ can be desorbed on acidification of the solution; however, the adsorption is never fully reversible. From acid-base titrations the adsorption of Co 2+ appears to modify the primary H + -OH - adsorption equilibria of the oxide surface.