Targeted accumulation and spatial confinement effect of Fe(II)-MOFs@MIP for efficiently removing low concentration dibutyl phthalate

Abstract

Sulfate radicals-based advanced oxidation processes are regarded as effective methods for removing organic contaminants. However, current removal technologies are often unable to achieve satisfactory results due to the low concentrations and high stability that are frequently characteristics for many types of organic contaminants. To improve the efficacy of using sulfate radicals to remove organic contaminants, we designed metal–organic frameworks (Fe(II)-MOFs) modified with enrichment and specific recognition of molecular imprinting layer (Fe(II)-MOFs@MIP). Using dibutyl phthalate (DBP) as the model target contaminant, the selectivity coefficient towards DBP was 7.28 for adsorption and 4.46 for catalytic degradation of Fe(II)-MOFs@MIP, which is excellent for most of the imprinted material. Additionally, we achieved the accurate recognition (169.25 μg × g−1) and efficient degradation (0.071 min−1) of DBP reducing levels to 100 μg × L-1. UV–vis analysis confirmed that specific recognition of DBP was mainly through hydrogen bonding and π-π interaction, while in-situ Raman and radical quenching experiments showed that the imprinting layer could accurately adsorb and produce the spatial confinement effects on target contaminants, thereby reducing the transfer distance of free radicals. As a result, we show that Fe(II)-MOFs@MIP can achieve efficient targeted degradation of DBP, opening up a new avenue for the removal of this and other highly stable organic contaminants present at low concentrations in environmental systems.