Adsorption-Sorption of Synthetic Organics

ORGANIC MATTER, NITROGEN, PHOSPHORUS, SYNTHETIC ORGANICS 

When the compound, representing a herbicide, contains an amino group, such a compound is referred to as basic. When fully deprotonated, its charge would be zero. When its pH equals its pKa, half of its functional sites would be positively charged and the other half would carry no charge. On the other hand, when its pH is two units below its pjKa, all its functional sites would be positively charged because of 100% protonation. 

Mineral surfaces appear to be more acid than the bulk solution. An equation that could be used to approximate clay surface pH (Stumm and Morgan, 1970) is 

Considering a mineral such as kaolinite at / = 0.01 and p0 = -0.1 V, substituting /0 into Equation 8.31 gives 

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