2008 Joint Annual Meeting (5-9 Oct. 2008): Surface Reactions at the Aluminum-Water Treatment Residual/Solution Interface as Determined by Flow Calorimetry and Phosphorus Modeling.
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580-4 Surface Reactions at the Aluminum-Water Treatment Residual/Solution Interface as Determined by Flow Calorimetry and Phosphorus Modeling.



Monday, 6 October 2008
George R. Brown Convention Center, Exhibit Hall E
Michael K. Miyittah1, Dean Rhue2, Jack Rechcigl1 and Craig Stanley1, (1)University of Florida, UFL-Gulf Coast Res. & Education Ctr, 14625 CR 672 enter 14625 Cr, Wimauma, FL 33598
(2)Soil and Water Science, University of Florida, 2129 McCarty Hall, P.O.Box 110290, Gainesville, FL 32611
Flow calorimetry was used to investigate the energetics of phosphorus (P) sorption reactions occurring at surfaces on amorphous aluminum water treatment residual (Al-WTR) and the effects on surface charge and ion exchange. Heats of exchange were determined using Cl/NO3 exchange. Exothermic reactions were observed when NO3 replaced Cl from anion exchange sites. At pH 5.8, Cl/NO3 heats of exchange were about 3.0-4.0 kJ/mol.  P sorption reduced the surface charge on Al-WTR as measured by Cl/NO3 exchange. Surface area analyses together with energetics suggest possible limited sites for adsorption. The use of flow calorimetry may clarify the mechanisms of P sorption at the Al-WTR surface.  The magnitude and energetics of phosphorus sorption were modeled and simulated using mathematical numerical methods. The time required for Al-WTR to reach full sorption capacity can be predicted from the simulation, which are however limited to traditional batch techniques. Further, time for all P to be immobilized from the system can also be predicted.
 
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