Polyaluminium Chloride 28% (PAC 28%)

Polyaluminium Chloride is a yellow or light-yellow powder. It is tasteless, harmless and non-toxic when in contact with humans or aquatic life. The substance dissolves in water with ease and can even absorb water from the atmosphere.

The substance is not reactive with most of the naturally occurring elements. However, it reacts with sodium bicarbonate to form a thick blanket of carbon dioxide. A foam stabilizer is added to the reaction to create a viable carbon dioxide layer that can effectively lock out oxygen from the burning material. This is the most common substance in many fire extinguishers used in Japan and India.

Given that Ferric alum is powder that does not burn when it is exposed to fire, it is commonly used in firefighting foams. When applied at the base of fire, it forms a blanket that prevents the combusting materials from accessing oxygen that is required for them to keep burning. Some water treatment firms use the salt for treatment of water. During the treatment of water, the electrons in the water hydrolyze fast forming combinations with various metal elements in water. They form slats that sediment at the base of the container and can be filtered away. Unlike many water purification agents, Ferric alum can work at very low temperature. This makes it ideal for water treatment during fall and winter seasons. The same compound works well in disinfecting and treatment of sewerage systems. It combines with organic matter and deals with the resulting odor.

Ferric alum appears as a white powder or crystalline. The crystalline and powder forms of the substance are soluble in water. However, it is not soluble in organic solvent such as ethanol. When in water, the solution appears clears and does not form a residue. Both of them are not toxic and do not catch flames. However, it can present an environmental hazard if spread in a large area.