Abstract
The leaching of potentially toxic elements or the generation of acidity often creates significant environmental pollution. Silica micro encapsulation using a silica solution, which was produced from diatomaceous earth of organic origin, is examined to prevent the release of harmful elements. This new approach has a long span of effectiveness because silica is chemically stable and leach-resistant. The surface of specimens taken from the overflow of the Matsuo sulfur mine was coated with the silica solution adjusted to various pHs at room temperature. Microanalyses by EPMA (electron probe microanalyzer) were performed on the specimens pre-treatment and post-treatment into higher pH, to certify the amorphous silica on the surface of harmful particles.
The results of leaching tests showed high performance remediation in the specimens, that is, iron and arsenic contents leached from specimens coated into the silica solutions at the pH value of 9 or 11, were less than 10ppm and 0.1ppm respectively, below the environmental quality standard, while those from the untreated specimens were about 280ppm and 6ppm, respectively.
