ionvahetusvõime

Ionvahetusvõime is a term used in chemistry and soil science to describe the capacity of a substance, typically a soil or a mineral, to exchange ions with a surrounding solution. This exchange is a reversible process where ions adsorbed on the surface of the substance are replaced by other ions present in the solution. The ability to exchange ions is primarily due to the presence of charged sites on the surface of the material. For example, soil particles, especially clays and organic matter, often have negative charges on their surfaces. These negative charges attract positively charged ions, known as cations, from the soil solution. Common cations found in soil solutions include calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+). The strength of the attraction between the charged sites and the ions influences the exchange process.

The ion exchange capacity is a crucial property that affects various soil processes. It plays a significant role in nutrient availability to plants, as essential nutrients like potassium and calcium are held in the soil by ion exchange and are released to plant roots in exchange for other ions. It also influences soil structure, buffering capacity, and the mobility of pollutants in the environment. The ion exchange capacity is typically measured in milliequivalents per 100 grams of soil or meq/100g, or more commonly today in centimoles of positive charge per kilogram of soil or cmolc/kg. Higher values indicate a greater ability of the soil to hold and exchange ions, which is generally associated with soils rich in clay and organic matter. Understanding ionvahetusvõime is essential for agricultural practices, environmental management, and water treatment processes that utilize ion exchange resins.