Alkaliniteti

Alkaliniteti is a measure of the buffering capacity of water or other solutions to neutralize acids. It reflects how much acid can be added before the pH changes by a given amount. In natural waters, alkalinity mainly arises from dissolved carbonate species, including bicarbonate (HCO3−), carbonate (CO3^2−), and to a lesser extent hydroxide (OH−). The presence of these ions allows the water to resist changes in pH when acids or acids produced by biological processes are introduced.

Alkaliniteti is not the same as pH. A water sample can have high or low pH while still having substantial alkalinity, which represents buffering capacity rather than current acidity. It is commonly expressed as milligrams per liter of calcium carbonate (mg/L as CaCO3) or as milliequivalents per liter (meq/L). Approximately 1 meq/L of alkalinity equals about 50 mg/L CaCO3.

Measurement typically involves a titration with a strong acid (for example, hydrochloric acid) until a specified pH endpoint is reached (often around pH 4.5). The amount of acid used defines the total alkalinity. In some contexts, a carbonate alkalinity portion is distinguished at higher pH endpoints.

Applications and importance: Alkalinity is crucial for buffering pH in freshwater and marine ecosystems, aquariums, and water treatment. Adequate alkalinity helps organisms withstand acidification and pH fluctuations. Conversely, low alkalinity can lead to harmful pH swings, while high alkalinity can influence chemical dosing in treatment processes.

Management: Alkalinity can be adjusted by adding buffering substances (e.g., sodium bicarbonate) to raise it or by processes that lower pH (with care to avoid harmful acidity).