Three-dimensional hierarchical porous graphene aerogel for efficient adsorption and preconcentration of chemical warfare agents

Abstract

The fabrication of advanced materials for the effective adsorption and monitoring toxic gases in ambient air is highly desirable. The present study reported on the preparation of three-dimensional (3D) porous graphene aerogel (GA) for efficient adsorption and preconcentration of chemical warfare agents (CWAs). A template assisted freeze casting followed by thermal reduction approach was employed to produce hierarchical porous graphene aerogel (HPGA). The resultant HPGA exhibits 3D interpenetrating micron and submicron hierarchical porous structure with excellent thermal stability and large specific surface area, which facilitates rapid diffusion of contaminated gas and thus helps dimethyl methylphosphonate (DMMP) molecules interact with the active adsorption sites through hydrophobic interaction. Thus the higher adsorption capacity was available on HPGA than that of ordinary GA and Tenax TA. For the application, the HPGA was further applied to the extraction of trace sarin from air samples in combination with thermal desorption gas chromatography-mass spectrometry (TD GC-MS). The sorbent exhibited excellent extraction efficiency towards sarin at comparatively high relative humidity owing to its hydrophobic property. The proposed method was reliable and sensitive and can be utilized in ambient air analysis with satisfactory recoveries.