Selenium Extraction from Soil by Alkali Metal Chloride
Selenium is an essential micronutrient for human and animal health, however, it is also a contaminant of soil and water due to industrial activity. Selenium can be extracted from soil using alkali metal chloride. This method is relatively simple and cost-effective, and has been widely used in research and industrial applications.
The first step in the extraction process is to prepare the soil sample for extraction by size reducing it to a moderate particle size. The particle size is important because it affects the rate of extraction and the yield of the recovered selenium. The next step is to pre-treat the sample with different reagents that are specific to the soil type and extract selenium. Alkali metal chloride is usually used to extract selenium because it is relatively inexpensive and non-toxic.
The alkali metal chloride will react with the soil to form selenates, which are soluble in water. The selenates can then be extracted from the soil by a series of steps. The first step is to adjust the pH of the solution to a neutral level (around 7). This is done by adding a basic solution, such as ammonia or potassium hydroxide, to the soil sample. The next step is to add an oxidant, such as hydrogen peroxide, which will convert the selenates into a soluble form which can be extracted from the soil.
Once the selenates are in a soluble form, they can be extracted from the soil sample using a liquid-liquid extraction process. The process involves mixing the soil sample with a solvent, such as isopropyl alcohol, which will solubilize the selenates. The solvent is then separated from the soil sample, and the selenates are recovered from the solvent. The recovered selenates can then be processed further and used as needed.
The alkali metal chloride extraction method is a relatively simple and cost-effective way to extract selenium from soil. It can also be used to extract a variety of other metals and minerals, such as cobalt and iron. This method is widely used in research and industrial applications, and has been proven to be an effective way to extract selenium from soil.
