Aluminium sulphate (

Al2(SO4)3cap A l sub 2 open paren cap S cap O sub 4 close paren sub 3
Al2(SO4)3
) is a versatile chemical primarily used as a coagulant in water purification and wastewater treatment to remove impurities. It is widely applied in the paper industry for sizing, in textile dyeing as a mordant, for adjusting soil pH to be more acidic, and in firefighting foams.