From Waste to Wealth: Exploring Spinel-Type Magnesium Slag as an Efficient Photocatalyst

Upgrading magnesium slag into value-added products provides a significant opportunity to address environmental waste pollution while promoting waste recycling. However, challenges such as the low catalytic activity of the resulting products and limited adsorption of macromolecular organic compounds at surface active sites remain critical engineering hurdles. In this paper, mesoporous g-C 3 N 4 /TiO 2 -MgAl 2 O 4 heterojunction photocatalysts were synthesized by a facile combustion method using magnesium slag, titanium dioxide, and carbamide as raw materials. Photocatalytic experiments on methylene blue solution under visible light irradiation at room temperature showed that the g-C 3 N 4 /TiO 2 -MgAl 2 O 4 heterojunction photocatalyst achieved a 25.6% higher degradation efficiency compared to traditional photocatalysts. This work provides a theoretical framework and practical experience for the value-added and low-cost preparation of photocatalytic materials derived from magnesium slag. Furthermore, a potential enhanced photocatalytic mechanism of g-C 3 N 4 /TiO 2 -MgAl 2 O 4 heterojunction photocatalysts is proposed.