A fully biobased gel foam based on sodium alginate/soy protein isolate with high stability and outstanding thermal resistance protection for inhibition coal spontaneous combustion

A fully biobased sodium-alginate/soy protein isolate gel foam was successfully prepared. • Thermal resistance performance test demonstrate that SS-GF treated coal reaches a maximum temperature reduction of 84.2%. • The fire-extinguishing efficiency of SS-GF increased by 73%. • The mechanism by which SS-GF inhibits coal spontaneous combustion was revealed. Coal spontaneous combustion endangers mine safety gravely. Coal spontaneous combustion fires not only release a large amount of toxic smoke, causing environmental pollution, but also seriously threaten the safety of mines. Gel foam materials possess favorable flowability, surface coverage and fracture-sealing capacity, and have shown promising application prospects in the prevention and control of coal spontaneous combustion. However, most gel foams have limited stability and water retention capacity. To address this issue, this study developed a high-stability gel foam (SS-GF) with sodium alginate (SA) and soy protein isolate as raw materials. SS-GF has excellent stability, water retention capacity and fire-extinguishing performance, thereby efficiently inhibiting coal spontaneous combustion. Compared with SA gel foam, SS-GF has significantly improved in water retention performance and structural integrity. SS-GF inhibited the heat accumulation on the surface of coal. Compared with raw coal, the maximum temperature was reduced by 84.2%. At 200℃, the CO inhibition efficiency of SS-GF treated coal reached 57.83%, and the oxygen consumption rate decreased by 40.3% compared with raw coal. Furthermore, SS-GF rapidly reduced the high-temperature coal from 963.73°C to 30°C within 100 min, improving the fire-extinguishing efficiency by 73% with no re-ignition. SS-GF can effectively prevent coal from contacting oxygen, inhibit the formation of active functional groups in coal, and delay the process of coal spontaneous combustion. This study provides a green and efficient strategy for the prevention and control of coal spontaneous combustion. Download: Download high-res image (186KB) Download: Download full-size image