Immobilization of iron phthalocyanine on 4-aminopyridine grafted polystyrene resin as a catalyst for peroxymonosulfate activation in eliminating tetracycline hydrochloride

A distinctive catalyst R-N-Fe was synthesized by anchoring iron phthalocyanine (FePc) covalently on chloromethylated polystyrene beads, which were pre-functionalized by 4-aminopyridine (4-ampy). Herein, pyridyl groups grafted on resins act as the axial fifth ligands to coordinate with FePc molecules. The obtained catalyst was characterized using N-2 adsorption-desorption, Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and zeta potential. The catalytic system based on peroxymonosulfate (PMS) activation was effective and stable for tetracycline hydrochloride (TCH) degradation, and activation energy of the TCH elimination using PMS activated by R-N-Fe was estimated to be 38.79 kJ/mol. Additionally, electron paramagnetic resonance (EPR) measurement combined with three different radical scavengers (ascorbic acid, methanol and tert-butyl alcohol) was conducted to confirm that sulfate radical (SO4 center dot-) and hydroxyl radical ((OH)-O-center dot) served as the main active species in the presence of PMS. Current findings suggested that the R-N-Fe/PMS system was a promising approach for the elimination of pharmaceutical compounds from aqueous solution.