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Phosphate adsorption at the porous glass/water and SiO2/water interfaces

1990; Elsevier BV; Volume: 134; Issue: 2 Linguagem: Inglês

10.1016/0021-9797(90)90139-f

1095-7103

Evangelos Dalas, Petros G. Koutsoukos,

Soil and Water Nutrient Dynamics

The adsorption of inorganic orthophosphate on porous glass and SiO2 surfaces has been investigated. Porous glass exhibited markedly higher affinity as compared to SiO2 toward phosphate, which was found to strongly depend on ionic strength and temperature. The phosphate uptake was relatively fast and the kinetics followed a simple first order equation. Adsorption data gave a satisfactory fit to a recently developed adsorption isotherm describing the adsorption of ions on heterogeneous surfaces, based on the classical Langmuir isotherm and assuming a Gaussian distribution of the free energies of adsorption.