The enhanced photocatalytic peroxymonosulfate activation for 2, 4-dichlorophenoxyacetic acid degradation over Z-scheme PTCDA/MIL-88A(Fe) under visible light

To attain significant synergy between adsorption and peroxymonosulfate (PMS) activation for the 2, 4-dichlorophenoxyacetic acid (2, 4-D) elimination, 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA)/MIL-88A(Fe) (PTxMy) composites were constructed by the facile ball-milling. The adsorption capacity of PT25M175 toward 2, 4-D was calculated as 76.0 mg/g at 308 K based on the Langmuir models. The decomposition of 2, 4-D in PT25M175/Vis/PMS system was investigated through a synergic action of adsorption and photocatalytic PMS activation, in which the optimum PT25M175 composite exhibited the 2, 4-D elimination efficiency up to 98.4 % within 10 min. The 2, 4-D degradation was mostly contributed by singlet oxygen (1O2) and superoxide radicals (O2•−), in which non-radical 1O2 accounts for a preponderant oxidation contribution (90.6 %). Based on LC-MS analysis, DFT computation, ecotoxicity analysis, and phytotoxicity evaluation, the 2, 4-D breakdown routes and the toxicity assessment of the degradation products were suggested. The elimination efficiency could be maintained at 97.9 % after five rounds of catalytic experiments. This study provided some guidance for compositing semiconductors with MOFs and utilizing a significant synergistic effect between adsorption and photocatalytic PMS activation to degrade organic pollutants.