Humic acid sodium salt is a complex mixture of multiple acids, which functions as a dibasic or tribasic acid. Structurally, Humic acid sodium salt is composed of carboxyl and phenolate groups, which result in this dibasic nature. This acid mixture is usually found in dead organic matter via biodegradation. Humic acid sodium salt can protonate carboxyl groups at a pK1 value of 4 and protonate phenolate groups at a pK1 value of 8. It is known that Humic acid sodium salt is important in regulating the bioavailability of metal ions as a result of its chelating properties to metal ions.
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