Full-component recycling with re-valorization from spent hydrodesulfurization catalyst: recovery of molybdates and synthesis of Ni2+ doped glass–ceramic

Hazardous wastes from the production of cleaner fuels, spent hydrodesulfurization (HDS) catalysts, pose a threat to the environment and the sustainability of rare metal resources. However, conventional recovery approaches are limited by long processes, easy generation of waste liquids, and difficult reuse of recovery products. Herein, a SiO₂–Na₂O–B₂O₃–MgO–TiO₂ glass phase extraction system was proposed for the full-component recycle from spent MoNi/γ-Al₂O₃ catalysts to the materials, including the individual recovery of Mo and the synthesis of Ni²⁺-doped glass–ceramics. 96.7% of Ni and 99.8% of Al were extracted into the loaded glass in one step, while 95.3% of Mo was precipitated as molybdate and directly recovered with high separation factors (SF_Mo/Ni 594.8, SF_Mo/Al 8718.2) in one step. Moreover, the broadband near-infrared luminescence (1150 − 1700 nm) of glass–ceramics was triggered by Ni²⁺ in the octahedral crystal structure of Me₃O₅ (Me = Mg, Al, Ti) by melting-annealing-crystallization processes, which provided it the potential to be applied in tunable lasers and broadband optical amplifiers for the wavelength-division-multiplexing transmission systems. The Ni²⁺-doping mechanism was calculated using molecular dynamics simulations. This work emphasized the maximization of the reuse value for each metal resource from hazardous wastes while reducing the burden on the environment and achieving the recycling of rare metal resources with re-valorization.

Graphical abstract