Removal of benzoic acid in aqueous solution by Fe(III) homogeneous photocatalysis

The behaviour of the system Fe(III)/Air/UV–benzoic acid is investigated in the pH range 2.0–5.5 and Fe(III) concentration up to 60 μM. The oxidation process develops through the establishment of an iron cycle in which HO radicals are produced by Fe(OH)2+ photolysis and the resulting Fe(II) photo-oxidized to Fe(III) by dissolved oxygen. A kinetic model is developed and used to simulate the behaviour of the system.