HR: 11:20h
AN: B11E-05    [PDF]
TI: Catalytic Interactions Involving Cerium, Catecholate, and Oxygen may be Pivotal to Phosphorus Bioavailability and Humic Acid Production
AU: * Cervini-Silva, J
EM: javiera@eps.berkeley.edu
AF: University of California at Berkeley, 151 Hilgard Hall #3110, Oakland, CA 94605 United States
AU: Banfield, J F
EM: jill@eps.berkeley.edu
AF: University of California at Berkeley, 151 Hilgard Hall #3110, Oakland, CA 94605 United States
AB: Highly insoluble cerium phosphate minerals form as the result of weathering of apatite and are important phosphorous repositories in soils. Prior studies have documented solubilization of these secondary phosphate phases in soils under some conditions, but the mechanisms are poorly understood. Here we report results of batch dissolution experiments under oxic and anoxic conditions, XRD, ATR-FTIR, and XPS analysis that suggest that catecholate catalyzes the oxidation of surface Ce3+ ions, resulting in formation of CeO2, a strong oxidant. The CeO2 then causes the decarboxylation of catecholate to form CO2, humic compounds, and soluble organic acids. The organic byproducts can further promote CePO4 dissolution by complexing with dissolved lanthanide ions. These processes may exert key controls on phosphate and organic carbon cycles in soils.
DE: 1045 Low-temperature geochemistry
DE: 1615 Biogeochemical processes (4805)
DE: 4851 Oxidation/reduction reactions
SC: Biogeosciences [B]
MN: 2003 Fall Meeting