Abstract:Ribbons with composition of Mg_71+xZn_24-xCa₅ (x=0, 2, 4 and 6) were prepared by melt-spun method. The influence of Mg content in the investigated alloys on amorphous structure formation, the decolorization ability and the recycle used times of the amorphous ribbons in degrading the direct blue (DB) azo wastewater were investigated. The results show that amorphous ribbons with thickness of 20-25 μm can be obtained when x≤4 for Mg_71+xZn_24-xCa₅ (x=0, 2, 4 and 6) alloys. The degrading rate and decolorization percentages increase with the Mg content for the amorphous ribbons when they act with the DB solution. Wherein, the degradation time when the solution become clear is 2 min, the characteristic time used to indicate the degrading rate is only 0.47 min, and the decolorization percentages calculated by absorbance rate is 95.41% for the Mg₇₅Zn₂₀Ca₅ amorphous ribbon. Furthermore, the amorphous structure is basically unchanged after the reaction for 60 min in wastewater for the ribbon, and the reacted products on the surface of the ribbons is the mineralization substance, which does not have the pollution characteristics. Mg₇₅Zn₂₀Ca₅ amorphous ribbons can be recycled at least 4 times while maintaining the degradation capacity of not less than 80%.

Key words: Mg-Zn-Ca; amorphous ribbon; direct blue azo dye; degradation ability; decolorization percentage; recycling use