Surface Charge Manipulation of Constant Surface Potential Soil Colloids: I. Relation to Sorbed Phosphorus1
- S. S. Wann and
- G. Uehara2
A significant correlation was found between the zero point of charge and the quantity of phosphorus applied to soil material from an Oxisol. Sorbed phosphorus lowered the zero point of charge and increased surface charge density at any pH above the zero point of charge. The soil was treated with 0, 100, 500, and 1,500 ppm P as (NH4)2HPO4. For the soil with no added phosphorus, low concentration of monovalent electrolyte and within two pH units of the zero point of charge, diffuse layer theory adequately predicted surface charge. For high electrolyte concentration and high pH, the Stern theory with specific adsorption energy predicted the experimental results. The calculated results indicated charge reversal in the high-phosphorus samples.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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