Degradation of salicylic acid coordinated to Fe3O4 nanoparticles by H2O2

Salicylic acid (SA) has strong tendency to form complexes with iron (III). Depending upon the concentrations of SA, the complexes formed are FeR + , FeR 2 + , FeR 3 2 + where R represents salicylate ion ( - OC₆H₄COO - ). Fe 3 O 4 nanoparticles binds with the salicylate ions through the sites having Fe 3+ and at the site containing Fe 2 + reacts with H 2 O 2 to produces OH* radicals. The OH* radicals oxidise the salicylic acid attached to Fe 3 O 4 nanoparticles. Thus, the degradation occurs through the formation of SA-Fe 3 O 4 nanoparticles complexes and then followed by the reaction with H 2 O 2 at the nanoparticle site. FT-IR, TGA were used to confirm the synthesis of Fe 3 O 4 nanoparticles as well as to investigate SA-Fe 3 O 4 nanoparticles complex formation and the degradation of the complex by H 2 O 2 . Spectrophotometric studies were employed for the monitoring of the degradation of SA at the surface. Here, the nanoparticles act as platform to which both the reactants SA and H 2 O 2 get activated and the degradation reaction occurs. The concentrations of SA, H 2 O 2 , nanoparticle dosage, surfactants and polymers were changed and the % degradation were noted. It has been observed that the degradation percentage decreased with the increase in nanoparticle dosage, [surfactant] and [polymers]. The [H 2 O 2 ] and [HClO 4 ] gave peaked-like curve for the degradation of SA for the plot of % degradation versus concentrations of H 2 O 2 and HClO 4 . Degradation of SA was observed maximum at [H 2 O 2 ](= 8.0 × 10 −4 mol dm −3 ) and at [HClO 4 ] (= 1.0 × 10 −2 mol dm −3 ).