Development of Fe(II) system based on N, N'-dipicolinamide for the oxidative removal of 4-chlorophenol

A novel catalyst system was investigated based on Fe-N, N'-dipicolinamide complex for the degradation of 4-chlorophenol (4-CP) by using hydrogen peroxide as an oxidant under mild alkaline conditions. This complex was stabilized by a ligand that assembles pyridyl and amide groups with a suitable linker. The optimization of the synthesized catalysts was evaluated in terms of the removal efficiency of 4-CP, by using Fe(II) and N, N'-1,2-phenyl-enedipyridine-2-carboxamide with a molar ratio of 1:1. The effects of reaction parameters on the oxidation of 4-CP were investigated by applying the selected catalyst with 4-CP removal rate of 99%. The results indicated that the pH and catalyst concentration could significantly affect the degradation rate of 4-CP. The mineralization level of 4-CP during the reaction was also examined, and almost 62.5% of 4-CP was absolutely mineralized into carbon dioxide and water. The preliminary analysis on the degradation mechanism indicate that the main active species are not hydroxyl radicals, and another kind of active species, called iron-oxo species, were proposed. This study explores a resultful linker between pyridyl and amide and presents a new method to expand the application of pH range of Fenton-like system.