Optimization and performance assessment of an eco-friendly three-phase gel foam for liquid fires based on experiments and molecular dynamic simulation

Existing fluorine-containing foams, widely used for suppression of tank fires, often fail to meet the requirements of environmental protection and safety. This study was aimed to develop an environmentally friendly three-phase foam fire extinguishing agent using biomass konjac glucomannan, silica aerogel, nanoparticles (Al(OH)3), and calcium hydroxide (Ca(OH)2). It utilized the high temperature environment to form a stable three-dimensional structure, exhibiting excellent heat absorption, cooling, and thermal insulation properties. Orthogonal tests were conducted to analyze the foamability and stability, thereby optimizing the foam formulations. The thermal stability, fire extinguishing, and fire resistance performance were examined, whereas the microscale mechanism was elucidated via molecular dynamics (MD) simulations. The experimental results indicated that Al(OH)3 promoted the formation of a carbonaceous layer, enhancing the thermal stability and insulation of the foam. When the mass ratio of silica aerogel to Al(OH)3 was 1:2, the foam demonstrated excellent fire extinguishing and fire resistant performance. MD simulation results showed that Ca2 + shifted the peak of the radial distribution function g(r) to the right by 0.08 Å, thus reducing aggregation of AEG molecules and increasing the stability of the foam. Additionally, Ca2+ increased the number of hydrated water molecules of AEG, leading to better water retention performance. The active free radicals generated by the decomposition of Al(OH)3 exerted an indirect chemical effect, enhancing water dilution efficiency. These results could help to further develop high-performance and environmentally friendly fire extinguishing agents.