Hierarchically porous glass-ceramics by alkaline activation and crystallization from municipal solid waste incineration ashes

As a hazardous waste, municipal solid waste incineration (MSWI) fly ash poses a serious threat to the environment, and considerable efforts have been made to achieve its harmless treatment. Herein, a novel approach for handling MSWI fly ash has been proposed to prepare porous glass-ceramics by alkali activation-crystallization, which overcomes the difficulty of controlling air bubbles under high temperatures. MSWI bottom ash rich in Al2O3 and SiO2 are co-treating as raw material to develop glass framework structure. The alkali activation mechanism shows that the development of MSWI ashes based basic glass from monomer to silica-aluminate gel under alkaline condition. The influence of H2O2 addition on the morphology and physical properties of porous glass-ceramics were evaluated. Porous glass-ceramics with uniform hierarchical pore structure have been fabricated at 3 mol/L NaOH, a solid loading of 55 wt%, and 1-4 wt.% H2O2, then crystallization treatment at 1150 degrees C for 2 h, the porosity and the bulk density of which varies from 77.22 to 82.94% and 0.68-0.91 g/cm(3) respectively, while their relatively high compressive strength ranges from 1.62 MPa to 3.85 MPa. Attributed to the hierarchical porous structure, uniform distribution of pores and excellent physical properties, porous glass-ceramics has potential applications in construction, filtration, and adsorption materials, providing a convenient and feasible method for the efficient and comprehensive utilization of MSWI ashes.