| 摘要 |
<p>A method for extracting metalloid and metal species from a solid or liquid m aterial by exposing the material to a fluid solvent, particularly supercritical carbon dioxide, containing a chelating agent is d escribed. The chelating agent forms chelates that are so luble in the fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical ca rbon dioxide and the chelating agent comprises a trialkyl phosphate, a trialkyl p hosphate, an alkyl-aryl phosphate, a trialkylphosphine o xide, a triarylphosphine oxide, an alkyl-arylphosphine oxide, and mixtures thereof. The method provides an environmentally benign process fo r removing contaminants from industrial waste. The method is particularly usef ul for extracting actinides from acidic solutions, and t he process can be aided by the addition of salts, such as nitrate salts, and mo difiers, such as water and the lower alkyl alcohols and esters. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient pro cess.</p> |
