Efficient adsorption of endocrine-disrupting pesticides from water with a reusable magnetic covalent organic framework
Abstract
A magnetic covalent organic framework (COF) is applied for the first time as adsorbent for the extraction of endocrine-disrupting pesticides from water. High adsorption efficiencies were found for lipophilic chlorpyrifos and atrazine, with calculated maximum adsorption capacities of 270 mg g(-1) and 54 mg g(-1), respectively, outperforming reported adsorbents, such as activated carbon, graphene, or metal-organic frameworks.
Polar diquat showed very poor adsorption efficiency, indicating that hydrophobic interactions play a role in the adsorption. Calculations revealed that the interactions between the COF and the pesticides are mainly based on van der Waals interactions.
Finally, recycling experiments showed that both pesticides can be recovered with an efficiency of over 90% using acetonitrile as solvent, with merely minor losses in adsorption capacity after five consecutive cycles of adsorption/desorption. The present study promotes further exploration of the possible application of COFs for the extraction and pre-concentration of pesticides in environmental matrices.