Photocatalytic and antimicrobial activity of decahedron-like MIL-125(Ti) anchored on AgI towards efficient degradation of tetracycline:activity evaluation, mechanism and pathway

Abstract

In this work, AgI nanoparticles were anchored on decahedron-like MIL-125(Ti) through wet precipitation method, and the photocatalytic activities were analyzed by tetracycline (TC) degradation rates under simulated sunlight. The structures, morphologies, valence bonds, optical absorption properties, charge separation efficiencies of the prepared samples were tested by XRD, SEM, EDS, XPS, UV–Vis DRS and PL spectroscopy. Compared with pure MIL-125(Ti), AgI@MIL-125(Ti) displayed excellent photocatalytic performance on TC degradation. When the mass fraction of AgI in AgI@MIL-125(Ti) was 10 %, AgI@MIL-125(Ti)-10 % displayed the best photocatalytic efficiency, which 96.9 % of TC was removed under simulated sunlight for 30 min. The results of active species trapping experiments and ESR tests showed that the Z-Scheme heterojunction between AgI and MIL-125(Ti) promoted the separation of photogenerated charges. Furthermore, a part of Ag+ were reduced to Ag NPs in the process of photocatalytic reaction, which constructed a cross-linking bridge for the charges at the interface of AgI and MIL-125(Ti) and further accelerated the electron transmission. The intermediate toxicity experiments proved that the toxic structures are destroyed in TC solution after MIL-125(Ti)-10 % photocatalytic degradation, and the toxicity of the reaction system was reduced effectively.