Synthesis of novel hydroxyl-functionalized hyper-crosslinked polymer for extraction of phenylurea herbicides from environmental waters

Abstract

Water resources are frequently contaminated by organic micropollutants (OMPs), which present a significant peril to ecosystem and well-being of the people. Phenylurea herbicides (PUHs) are an important class of OMPs since they are widely used in modern agriculture. However, efficient extraction of PUHs from water is of challenge because of their high water affinity. Therefore, the synthesis of novel adsorbent capable of effectively extracting PUHs from water is urgently needed. Here, three novel hydroxyl-functional hyper-crosslinked polymers (HCPs) were synthesized through Friedel-Crafts reaction by using the brominated β-cyclodextrin, i.e., heptakis(6-bromo-6-deoxy)-β-CD) [(CD-(Br)7)], as the building unit. Among them, PQ-CD-HCP, which was synthesized by using p-quaterphenyl (PQ) and CD-(Br)7, had the best adsorption capability for the PUHs. Finally, the quantitative determination of the PUHs for environmental waters was realized by using the PQ-CD-HCP as the solid-phase adsorbent in conjunction with high-performance liquid chromatographic detection. Under the optimal conditions, the limits of detection for environmental water samples were 0.02–0.05 ng mL−1. The method recoveries were 86.0%-116.5% with the relative standard deviations ≤ 7.8%. The PQ-CD-HCP also showed good adsorption performance for other OMPs such as triazine herbicides, chlorophenols, polycyclic aromatic hydrocarbons, endocrine disruptors, nitroimidazoles and benzoylureas insecticides, indicating its good application prospect. The adsorption experiments show that the PQ-CD-HCP extracts the analytes by encapsulation, π-stacking, hydrophobic and hydrogen bonding interactions.