Perylene diimide configuration to construct g-C3N4 and iron phthalocyanine composite catalyst as PMS activator for contaminant degradation

Abstract

The photocatalysis-assisted peroxymonosulfate (PMS) activation process has shown great potential for organic wastewater treatment. Herein, the composite photocatalyst (FeTAPc/PDI/CN) was obtained by grafting graphitic carbon nitride (CN) and amino iron phthalocyanine (FeTAPc) onto both ends of perylene tetracarboxylic anhydride (PTCDA) through an imidization process. Under simulated solar irradiation, the catalyst exhibited a remarkable degradation performance toward the target pollutant by activated PMS over a wide pH range from 3 to 11. The degradation efficiency of SMX reached 100 % in 7 min with the reaction kinetic constant of 0.845 min−1, which was 13 times higher than that of pure CN. In addition, the removal rate of FeTAPc/PDI/CN-4 for SMX was more than 80 % after 9 cycles. The introduction of phthalocyanine and PDI improved the separation efficiency of photogenerated electron-hole pairs. Furthermore, the active species involved in the SMX degradation were identified as •OH, SO4•-, •O2– and 1O2. The possible degradation pathways were proposed based on the identified intermediates, in which the oxidation of the amino group on the benzene ring was the main degradation pathway. This study is anticipated to result in a favorable method for designing CN-based photocatalysts with high stability and excellent catalytic activity for environmental remediation.