At pH 10, the heat of complex formation tends to be more endothermic and is approx. 0 at pH 13. The addn. of urea to PAA at pH 13 resulted in an exothermic heat of complex formation of 1.41 kcal mol-1 ...

Humic-like substances (HULIS) are macromolecular complex groups in water-soluble organic compounds (WSOC). pH is a crucial factor that influences the chemical transformations of HULIS in atmospheric ...