Polyacrylonitrile-supported symmetrical configuration pyridine bridged bi-iron phthalocyanine nanofibers for efficient degradation of carbamazepine in the presence of peroxymonosulfate

Abstract

In this study, the 4-aminopyridine (Py) was employed to link with terephthaloyl chloride (TPC) through amide bonding to generate the symmetric ligand Py-TPC, and the iron phthalocyanine (FePc) was axially coordinated with Py-TPC to synthetic the composite catalyst FePc-Py-TPC. By introducing Py-TPC, the π-π conjugated stack structure within phthalocyanine molecules was disrupted and more active sites were exposed. FePc-Py-TPC was dispersed in polyacrylonitrile (PAN) through electrospinning to obtain FePc-Py-TPC/PAN nanofibers, which solved the problem of difficult recycling and utilization of powder catalysts. FePc-Py-TPC/PAN can effectively activate peroxymonosulfate (PMS) at room temperature, and the removal rate of carbamazepine (CBZ) approaches 100 % within 40 min. After five recycles for CBZ degradation over the FePc-Py-TPC/PAN/PMS system, the removal ratios of CBZ remained at 90 %. O²⁻ is the main active radical, SO₄⁻, OH, and ¹O₂ play a secondary role. Six intermediate products and two final products of CBZ were identified by ultra-performance liquid chromatography and high-definition mass spectrometry, and the possible degradation pathways were speculated. All CBZ and the aromatic intermediates were eventually converted into small acids.