Iron and Copper Catalysts Derived from Inorganic Waste for Dye Degradation

Abstract

Dyes like methyl violet (MV) and methyl orange (MO) released from textile industries are considered to be water pollutants. Likewise metal waste from electronic devices and from metallurgical industries are causing harmful effects. Therefore, looking into the negative impact of such waste materials herein copper oxide (CuO) and iron oxide (Fe 3 O 4 ) photocatalysts were prepared from electronic and candle waste, respectively materials. The metal oxides were supported on a graphitic carbon matrix obtained from waste tea leaves. The synthesized materials were well characterized using different analytical techniques. The carbon-supported CuO and Fe 3 O 4 catalysts exhibited good photocatalytic activity under UV-light irradiation in the photo-degradation of coloured dyes like methyl orange (MO) and methyl violet (MV). The copper (Cu)-catalyst with band gap like that of titanium dioxide (TiO 2 ) showed superior activity over the iron (Fe)-catalyst under identical conditions. Cu-catalyst was found to degrade the dyes within 10-15 min while it took longer time with Fe-catalyst up to 50 min. The measure of total organic content (TOC) after the dye-degradation study implied that Cu-catalyst can carbonize MV upto 89.6 % within 15 min while the same was found to be less (79.5 %) for MO. The ability of the synthesized photocatalysts from waste materials in dye degradation was monitored through FTIR analysis. The mechanistic study suggested the involvement of both the holes and free radicals in the photooxidation of dye components.

Hydrothermal Synthesis and Photocatalytic Activity of NiTiO3 for the Degradation of Malachite Green under Visible Light Irradiation

“…From these results, it is clear that the surface‐bound (OH*) radicals and holes have the principal role in the oxidation of MG in the presence of a titanium‐based photocatalyst ($${{{\rm N}{\rm i}{\rm T}{\rm i}{\rm O}}_{3})}$$ . Moreover, the degradation process occurred mainly on the external surface rather than the catalyst used [74,75] …”