Highly Efficient Removal of Neonicotinoid Insecticides by Thioether-Based (Multivariate) Metal-Organic Frameworks

Circumventing the impact of agrochemicals on aquatic environments has become a necessity for health and ecological reasons. Herein, we report the use of a family of five eco-friendly water-stable isoreticular metal-organic frameworks (MOFs), prepared from amino acids, as adsorbents for the removal of neonicotinoid insecticides (thiamethoxam, clothianidin, imidacloprid, acetamiprid, and thiacloprid) from water. Among them, the three MOFs containing thioether-based residues show remarkable removal efficiency. In particular, the novel multivariate MOF {(SrCu6II)-Cu-II [(S,S)-methox](1.)(5) [(S,S)-Mecysmox](1.50) (OH)(2) (H2O)}center dot 36H(2)O (5), featuring narrow functional channels decorated with both -CH2SCH3 and -CH2CH2SCH3 thioalkyl chains-from L-methionine and L-methylcysteine amino acid-derived ligands, respectively-stands out and exhibits the higher removal efficiency, being capable to capture 100% of acetamiprid and thiacloprid in a single capture step under dynamic solid-phase extraction conditions-less than 30 s. Such unusual combination of outstanding efficiency, high stability in environmental conditions, and low-cost straightforward synthesis in 5 places this material among the most attractive adsorbents reported for the removal of this type of contaminants.

Automated summary

This study introduces a family of eco-friendly water-stable metal-organic frameworks made from amino acids for the removal of neonicotinoid insecticides from water. Among them, those with thioether-based residues exhibit remarkable removal efficiency, with a novel multivariate MOF showing the highest efficiency in capturing acetamiprid and thiacloprid in less than 30 seconds. These MOFs demonstrate outstanding efficiency, stability, and cost-effective synthesis, positioning them as top adsorbents for this type of contaminants.