Preparation of environmental-friendly foam extinguishing agent based on inorganic salt and polysaccharide mixtures for firefighting diesel pool fire

The environmental-friendly foam extinguishing agent was prepared with sodium alpha-olefin sulfonate (AOS) and phosphate betaine silicone surfactant (PBSS) as surfactants, inorganic salts and polysaccharide polymers as foam stabilizers. The effects of the mixture of inorganic salts and polysaccharide polymers on the surface tension, foaming ability, foam stability and fireextinguishing efficiency of foam extinguishing agent were studied. The results showed that the addition of xanthan gum/gelatin/0.1 % MgCl2 imparts the optimal properties to foam extinguishing agent, which is ascribed to the electrostatic interaction between Mg2+ and the head group of the AOS/PBSS surfactant, thereby reducing the electrostatic repulsion between the head groups, and further improving the stability of the foam. Besides, the xanthan gum/gelatin/0.1 % MgCl2 foam extinguishing agent possesses higher water capacity, which allows the decomposition of foam to produce higher concentration of ammonia, phosphoric acid and water vapor in the firefighting application, and improving the fire extinguishing efficiency and burning resistance of the foam extinguishing agent. The results of the investigation may provide theoretical guidance for the development of environmental-friendly foam extinguishing agents.