In-situ construction of AgI nanoparticle-decorated covalent triazine-based frameworks heterojunction with enhanced photocatalytic performance for the degradation of persistent organic pollutants

Abstract

In this paper, a multitude of novel CTF-1/AgI (CTFA-x) type-Ⅱ heterojunction were fabricated by in-situ growth approach based on the stable covalent triazine-based framework CTFs. 2D CTF-1 with sufficient nitrogen sites anchored AgI to its matrix, supporting ample active sites for CTFA to degrade ciprofloxacin (CIP) in aqueous solution. The structural and physicochemical characteristic of the CTFA products were explored by TEM, XRD, XPS, FT-IR, BET and PL characterization. The respective roles and synergistic effects of AgI and CTF-1 are discussed. Benefiting from this unique structure, the CTF-1/AgI with the mass ratio of 1:1 (CTFA-50) demonstrated the highest photocatalytic capacity and showed a degradation efficiency of more than 90 % against CIP after 120 min under simulated sunshine irradiation. Compared to pure AgI and CTF-1, the apparent rate constant for the CIP photodegradation of CTFA-50 (0.0153 min−1) was found to be 6.7 and 8.5 times greater. The CTFA-50 catalyst possessed good structural stability and broad-spectrum applicability, and had the ability to efficiently degrade various stubborn organic matters including tetracycline (87.97 %), 2-sec-butyl-4,6-dinitrophenol (63.42 %), bisphenol A (68.22 %), rhodamine B (98.62 %), methyl orange (70.25 %), methylene blue (63.27 %). As demonstrated by the results of the radical trapping tests and EPR analysis, the photodegradation process of CIP was mostly mediated by •O2– and h+. In view of the LC/MS findings, all reaction intermediates could be determined and a reasonable photocatalytic mechanism was proposed.