A solar-driven unmanned hazardous and noxious substance (HNS) trapping device that can absorb, evaporate, condense, and collect HNSs was prepared. The HNS trapping device was composed of three parts: a reverse piloti structure (RPS) for absorption and evaporation of HNSs, Al mirrors with optimized angles for focusing light, and a cooling line system for the condensation of HNSs. The RPS was fabricated by assembling a lower rectangle structure and an upper hollow column. The lower rectangular structure showed a toluene evaporation rate of 6.31 kg/m2 h, which was significantly increased by the installation of the upper hollow column (11.21 kg/m2 h) and led to the formation of the RPS. The installation of Al mirrors on the RPS could further enhance the evaporation rate by 9.1% (12.28 kg/m2 h). The RPS system equipped with an Al mirror could rapidly remove toluene, xylene, and toluene-xylene with high evaporation rates (12.28-8.37 kg/m2 h) and could effectively collect these substances with high efficiencies (81-65%) in an unmanned HNS trapping device. This prototype HNS trapping device works perfectly without human involvement, does not need electricity, and thus is suitable for fast cleanup and collection of HNSs in the ocean.
Keywords: absorbents; evaporation; hazardous and noxious substance; oil/water separation.