MgZn-based amorphous ribbon as a benign decolorizer in methyl blue solution

Abstract The AZ91D (AZ91), Mg78Zn22 (MZ) and Mg73Zn22Ca5 (MZC) alloys are cast in ingots and then spun in ribbons with crystalline, semi-amorphous and fully amorphous structures, respectively. The α-Mg dendritic degree of ingots ranks as AZ91 ≤ MZ ≤ MZC. Three as-spun ribbons have a similar decolorization rate constant k on methyl blue (MB) solution; the immersed amorphous MZC ribbon has a much higher k than its as-spun counterpart, while the immersed AZ91 and MZ ribbons have a much lower k than their as-spun counterparts. The immersed MZC ribbon has an excellent reusability in MB decolorization due to the developed nanoporous luffa-sponge-like structures on ribbon surface, which possibly can be ascribed to the intrinsic netlike structural units in the amorphous and liquid states and to the structural heredity during solidification. This work not only provides a benign, efficient and low-cost decolorizer for the synthetic dyes, but also expands the application field of Mg-based amorphous alloys.