Ferric Phosphate Precipitation (Water Treatment)

FeCl₃ + Na₃PO₄ → FePO₄↓ + 3NaCl

Overview

Iron(III) chloride reacts with trisodium phosphate to form an insoluble yellowish-white precipitate of iron(III) phosphate (Ksp = 9.9 × 10⁻¹⁶). This precipitation is the primary method for removing phosphate from wastewater to prevent eutrophication of receiving waters.

Participants

Role	Substance	Coefficient	State
Reactant	Iron(III) Chloride FeCl₃	1	(aq)
Product	Sodium Chloride NaCl	3	(aq)

Everyday Example

Iron phosphate is used as an organic slug bait in gardens, sold under brand names like Sluggo. It is safe around pets and wildlife.

Industrial Importance

Phosphate removal by iron(III) precipitation is a critical step in wastewater treatment worldwide, preventing algal blooms and eutrophication in lakes and rivers.

Properties

Type: Precipitation
Reversible: No
Energy: Exothermic
ΔH: -95.0 kJ/mol

Related Reactions

Aluminum Hydroxide Precipitation Barium Carbonate Precipitation Barium Sulfate Precipitation Cadmium Sulfide Precipitation (Yellow) Calcium Carbonate Precipitation Calcium Fluoride Precipitation (Fluorite) Calcium Oxalate Precipitation (Kidney Stones) Calcium Phosphate Precipitation (Bone Mineral) Calcium Sulfate Precipitation (Gypsum) Chromium(III) Hydroxide Precipitation

Frequently Asked Questions

What is the equation for Ferric Phosphate Precipitation (Water Treatment)?

The balanced equation is: FeCl₃ + Na₃PO₄ → FePO₄↓ + 3NaCl.

What type of reaction is Ferric Phosphate Precipitation (Water Treatment)?

Ferric Phosphate Precipitation (Water Treatment) is a precipitation reaction.

Is Ferric Phosphate Precipitation (Water Treatment) exothermic or endothermic?

Ferric Phosphate Precipitation (Water Treatment) is exothermic (releases energy). The enthalpy change (ΔH) is -95.0 kJ/mol.