Post-modified linker functionalization of metal organic frameworks for high-efficiency adsorption and quantification of trace organophosphorus pesticides in environmental water

Water pollution caused by organophosphorus pesticides (OPPs) from agricultural production causes vital great threat to mankind lives and thus developing a method for rapid removal and detection of OPPs is urgent. In this work, we proposed the linker functionalization of metal organic frameworks (UiO-66) by post-modification to generate defects and active sites for tailoring their adsorption behavior. The metal organic frameworks (MOFs) modified by functional groups (amino and pyridine) exhibited similar physicochemical property and pore structure. The UiO-66-PA exhibited an excellent performance of rapid adsorption of OPPs in water with average capacity of 246.55 mg/g. Experimental characterizations and theoretical simulations revealed that the enhanced binding energy between UiO-66-PA and OPPs resulted from synergistic interaction between pyridine and OPPs via nucleophilic effect, π-π interaction, and metal electronic interaction, boosting the adsorption capacity and removal efficiency, which suggested that functional group plays important role in improving performance. When used it as adsorbent for analysis of OPPs in water coupled with ambient ionization source, UiO-66-PA exhibited an excellent performance of the quantitative detection of OPPs in water with limit of detections (LODs) of 0.076–––0.251 ng/mL and relative standard deviations (RSDs) of 1.13 % − 5.84 %. In addition, the proposed analytical method could be applied in analysis of three environmental water samples with great sensitivity, anti-interference and reusability, which demonstrated that UiO-66-PA afforded outstanding selectivity for OPPs and could be appropriate for high-throughput screening and on-site analysis. This work could provide a novel method to design MOFs-based adsorbents with functions of removal and purification via post-modification and exhibit a great potential to rapid analysis of OPPs in environmental water.