'smart' Sand for Buried Explosive Detection By Naked Eye Under Handheld UV Light

In this study, explosive-sensitive fluorescent sand (‘smart’ sand) was prepared through simple coating technology. The properties of the as-prepared ‘smart’ sand were characterized by SEM, EDS, XRD, FT-IR, UV-vis and fluorescence emission spectra. The characterization results indicated that fluorescent explosive-sensing composite film was successfully coated on the surface of sand, and thus the ‘smart’ sand displayed strong fluorescence. The as-prepared ‘smart’ sand was further applied for the detection of buried explosives.  Different amounts of 2,4-DNT were buried in soils with different depth. Then the ‘smart’ sand was ‘sprayed’ on the soil surface. Under handheld UV light, the fluorescence of ‘smart’ sand is strongly quenched by leaked explosive vapors, which can be visualized by naked eye. In addition, emission spectra of quenching spot and non-quenching spot after detection were collected to corroborate the quenching mechanism. This result indicates that ‘smart’ sand has the potential to be applied for large-scale landmine detection and mapping.