Organophosphorous pesticide removal from water by graphene-based materials - Only adsorption or something else as well?

Abstract

The extensive use of pesticides requires innovative approaches to remove these compounds from the environment. Carbon materials are traditionally used as adsorbents for removing pesticides, and the development of the new sorts of carbon materials allows more advanced approaches in environmental applications. Using density functional calculations, we have predicted chemical reaction between the S(O)=P moieties of the organophosphates with point defects in graphene - single vacancies, Stone-Wales defects and epoxy-groups. The reaction was confirmed using ultra high performance chromatography for two graphene oxide samples and dimethoate as a representative of organophosphates. The exact reaction mechanism is still elusive, but it is unambiguously confirmed that no selective oxidation of dimethoate to more toxic oxo-analog occurs. The presented results can help to develop novel systems for the irreversible conversion of organophosphates to non-toxic compounds, without using aggressive chemical agents or external physical factors like UV radiation.