Surface precipitation in the Co(II)/Al_2O_3 sorption system

摘要

Surface precipitation is a critically important process in many systems of scientific and technological importance, such as modeling the segregation of contaminants from aqueous to solid phases in groundwater and the dispersion of active phases on catalyst supports. XAFS and TEM studies of Co(II) sorbed on Al_2O_3 indicate clearly that surface precipitates have formed from solutions that are undersaturated with respect to any known bulk solid Co-bearing phase. These studies indicate that the structure of the precipitates is similar to that of Co(OH)_2(s), but it is disordered and has a high concentration (about 30