High efficiency decolorization of azo dye Reactive Black 5 by Ca-Al particles

This work studies the degradation of azo dye Reactive Black 5 by Ca-Al metallic particles prepared by melt-spinning and ball-milling. The morphology and the phase structure of the metallic powders were characterized and the decolorization efficiency of Reactive Black 5 solutions were assessed by monitoring the dye degradation by ultraviolet-visible absorption spectrophotometry. The decolorization process using the Ca-Al powders showed fast kinetics and high efficiency. 40 mg L−1 dye solution was successfully decolorized in 1 min using 0.1 g/100 mL of Ca65Al35 powder, suggesting it as an effective, low-cost means for degradation of azo-compounds.