Eco-friendly chitosan-based hydrogel for coal dust suppression via salting-out effect

Coal mining-related dust pollution poses significant threats to ecological integrity, occupational health, and industrial sustainability. Conventional dust suppressants, however, suffer from inherent limitations such as inadequate capture efficiency, poor water retention, and a tendency to cause secondary pollution. To overcome these challenges, this study developed a novel bio-based chitosan hydrogel dust suppressant using highly deacetylated chitosan and sodium citrate via an innovative salting-out method. By acting as both a salting-out agent and a pH regulator, sodium citrate enhances the binding affinity with coal dust to improve suppression performance. Its dust suppression primarily occurs through synergistic mechanisms including electrostatic adsorption, moisture retention/locking, and physical coverage. After 72 h, the hydrogel dust suppressant maintained a water retention rate close to 75%. Its wind erosion resistance rate remained at approximately 99% within 3-7 days, and its degradation rate reached about 96% within 25 days. Notably, compared to conventional materials, this formulation exhibits excellent biodegradability, with its carbon-containing degradation products providing nutrients for plant growth. This green multifunctional system avoids complex preparation processes, integrating high-efficiency dust suppression, environmental safety, and ecological compatibility. It demonstrates significant application potential in sustainable mining practices.