Used as a coagulant in water and wastewater treatment to remove suspended solids, phosphates, and other contaminants. It helps clarify water by forming flocs that settle easily. Commonly applied in municipal sewage treatment and industrial effluent treatment. Also used in soil stabilization and as an etching agent in printed circuit board manufacturing. In agriculture, it can be used to lower soil pH and treat iron deficiency in plants. Additionally, it serves in the production of other iron compounds and in leather tanning processes.