sodiumphosphate

Sodium phosphate is a family of inorganic salts derived from phosphoric acid (H3PO4) by replacing one or more acidic hydrogens with sodium ions. The principal members are monosodium phosphate (NaH2PO4), disodium phosphate (Na2HPO4), and trisodium phosphate (Na3PO4). These salts are typically white, crystalline solids that dissolve readily in water and form solutions with buffering capacity over a range of pH values.

In solution, they act as buffers based on the phosphate system, with monosodium phosphate yielding mildly acidic solutions, disodium phosphate giving near-neutral to basic solutions, and trisodium phosphate producing strongly basic solutions. They are produced industrially by neutralizing phosphoric acid with sodium hydroxide or sodium carbonate, and are also derived from mining and processing of phosphate rock.

Uses include food industry applications as acidity regulators and sequestrants (often sold as additives under E339 in various forms), as well as buffering agents in processed foods. They are also employed in cleaning products and detergents as builders and pH adjusters, and in certain laxative formulations as osmotic agents. In water treatment, phosphate salts help prevent corrosion and control hardness.

Safety considerations: these salts are generally recognized as safe in appropriate amounts for food use, but excessive intake can disrupt electrolyte balance, particularly in individuals with kidney impairment or heart disease. Environmental concerns arise from phosphate discharge, which can contribute to eutrophication in aquatic systems.