The impact of the structure of graphene-based materials on the removal of organophosphorus pesticides from water

Abstract

The wide use of pesticides in modern agriculture and other areas results in an urgent need for their efficient removal from the environment. Adsorption of pesticides is one of the most commonly used strategies for this task. Here we analyze the adsorption of two organophosphorus pesticides, dimethoate (DMT) and chlorpyrifos (CPF), on graphene-based materials. The adsorption was found to be very sensitive to the structure of the adsorbents used. In particular, aliphatic DMT was found to prefer hydrophilic oxidized graphene surfaces. The CPF molecule, which contains an aromatic moiety, prefers adsorption on the surface of a graphene basal plane with high structural order and preserved π electron system. The toxicity of pesticide solutions is reduced after adsorption, suggesting that there is no oxidation of DMT and CPF to more toxic oxo forms. We emphasize that the combination of structural properties of adsorbents and adsorbates defines the adsorption of organophosphorus pesticides on graphene-based materials, while the specific surface area of adsorbents is not the major factor.