HEDP (Hydroxyethylidene Diphosphonic Acid) and its tetrasodium salt, HEDP-Na4, are both important ingredients in self-cleaning formulations, and each of them has unique characteristics and advantages. The following is a comparison of HEDP and HEDP-Na4 in self-cleaning agent formulations:
I. Comparison of basic properties
Ingredient HEDPHEDP-Na4 Chemical formula C2H8O7P2C2H4Na4O7P2-4H2O (tetrasodium salt form) Physical state Pure product is white crystals, industrial products are colourless to light yellow transparent liquid – Solubility Soluble in water Soluble in water stability Structural stability, not easy to hydrolyse –
Second, the function comparison
- Chelating ability:
- HEDP: has strong chelating ability, can complex the metal ions in water, such as calcium, magnesium, iron, etc., to prevent them from forming difficult to remove scale and stains.
- HEDP-Na4: also has a strong complexing ability, and due to its tetrasodium salt form, it may have better solubility and dispersion in aqueous solution, thus removing stains more effectively.
- Stain Removal Power:
- HEDP: It is able to remove stains adhering to the surface, such as iron oxide, passivation layer, etc., and maintain the self-cleaning effect.
- HEDP-Na4: also has excellent detergency and, due to its good solubility in water, may penetrate more easily inside the stain for more thorough cleaning.
- Antioxidant properties:
- HEDP: It can form stable complexes with metal ions, preventing oxidation reaction of metal ions and thus extending the service life of self-cleaning materials.
- HEDP-Na4: also has antioxidant property, and may have longer service life and better stability due to its stable tetrasodium salt structure.
Third, application comparison
- Scope of application:
- HEDP: It is not only used in the formulation of self-cleaning pigment, but also widely used as scale and corrosion inhibitor in the treatment of boiler water, circulating water and oil field injection water.
- HEDP-Na4: In addition to self-cleaning agent formulation, it is also used in circulating cool water system, low pressure boiler, oil field water injection and oil pipeline in electric power, chemical industry, metallurgy, fertiliser and other industries.
- Precautions for use:
- Both need to be mixed with water in a certain proportion when used to avoid too high or too low concentration affecting the cleaning effect.
- As self-cleaning agents usually contain strong alkaline components, protective gear is required to minimise damage to the skin, eyes and respiratory tract.
- When storing, it is necessary to protect it from moisture and keep the container sealed and away from flammable substances and oxidising agents.