The photocatalytic degradation of amino and nitro substituted stilbenesulfonic acids by TiO2/UV and Fe2+/H2O2/UV under aqueous conditions

The photodegradation products of 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNSDA), 4-amino-4′-nitrostilbene-2,2′-disulfonic acid (ANSDA) and 4,4′-diaminostilbene-2,2′-disulfonic acid (DASDA) imparted by UV, TiO2/UV and Fe2+/H2O2/UV were characterized by IC, HPLC and LC-ESI-MS/MS. Direct photolysis with UV light allowed the transformation of trans-isomers to the corresponding cis-isomers followed by degradation to aromatic aldehydes and carboxylic acids. Whilst both TiO2/UV and Fe2+/H2O2/UV processes mineralized the model compounds, Fe2+/H2O2/UV process was more rapid than TiO2/UV.