Mechanism of chelating agent action

Chelating agents are chemical substances containing chelating groups that can form complexes (also known as coordination compounds) with metal ions. The mechanism of action of chelating agents mainly involves the following aspects:

Ion exchange: There are a large number of metal ions (such as calcium, magnesium, iron, etc.) in water, which combine with anions (such as SO4 ^ 2-, CO3 ^ 2-, etc.) to form insoluble salt precipitates. Chelating agents can undergo ion exchange reactions with these metal ions, causing them to combine with chelating agents to form water-soluble complexes, thereby reducing the formation of salt precipitates.

Bonding: A complex formed by the coordination bond (also known as chemical bond) between the chelating group (usually carboxylic acid group or amino group) of a chelating agent and metal ions. This coordination bond is usually formed by one or more organic molecules or ions surrounding the center of metal ions, which are called ligands. The complex formed with metal ions has high stability and is not easily replaced by other ions in water, thereby reducing its adverse effects on water.

PH regulation: The chelating ability of chelating agents is usually influenced by the pH value. Under suitable pH conditions, chelating agents can form stable complexes with metal ions. For example, the complexation reaction between EDTA and calcium ions is h3est at around pH 7-8.

In summary, chelating agents alter the properties and distribution of metal ions by forming stable complexes, thereby achieving control and reduction of scale and salt precipitation in water. In practical applications, the selection and use of chelating agents need to refer to water quality characteristics and specific application requirements to achieve the best results.