Targeted degradation of dimethyl phthalate by activating persulfate using molecularly imprinted Fe-MOF-74

Abstract

Adsorptive removal of dimethyl phthalate (DMP) in water combined with advanced oxidation processes (AOPs) has attracted interest. In this work, the adsorptive and catalytic properties of an Fe-based metal-organic framework (Fe-MOF-74) have been improved by molecular imprinting technique. The adsorption behaviors have been evaluated by the Freundlich and pseudo-second-order model. The results have shown that selective adsorption ability of the material for DMP was highly enhanced and chemisorption was dominating. A 1.5-fold increase in catalytic rate after being modified by molecular imprinting indicated that the selective adsorption is crucial. In the synergy of adsorption and catalysis, DMP was first specifically adsorbed on the surface of the material by hydrogen bonds and electrostatic interactions. Then, hydroxyl radicals and sulfate radicals, which were both generated via activation of persulfate (PS), catalytically oxidized DMP. The degradation rate can rapidly reach around 90% in 30 min and three possible degradation pathways were proposed. The molecular imprinting modified catalyst can be used for DMP effective degradation in water.

Keywords: Dimethyl phthalate; Fe-MOF-74; Molecular imprinting; Persulfate.