Revealing A New Transport Form Of Natural Material By Naturally Occurring Spherical Amorphous Silica Particles In Soil Aerosol

Much attention is currently being paid to the behaviour and effects of engineered silica particles, but there is only limited information available on the natural silica particles. In this study, we have found for the first time that natural silica can occur as spherical amorphous nanoparticles and silica fine disperse particles in the soil aerosol after studying nine areas from northern to southern China. These particles are usually 10 to 600 nm in diameter and contain a high content of impurities. Amorphous nature of the particles has been proved by the electron diffraction images. These findings indicate that nanoparticles and fine disperse particles in vapor phase could be an important transport form for natural silica and during the transportation in the vapor phases many elements could also accompany nanoparticles and finely disperse particles. The aggregative growth of SiO2 nanoparticles is also observed for the first time in the natural system. In addition, these particles may be a perfect candidate to prospect blind ore.