Waste toner-derived porous iron oxide pigments with enhanced catalytic degradation property

'Wealth from Waste' is an emerging concept, since it leads an effective waste treatment and waste recyclability. On the other hand, cost effective production iron oxide (IO) nanomaterials is still needed to develop, owing to their wide applications. Herein, we proposed a simple direct calcination method to prepare porous IO (Fe3O4 and Fe2O3) nanomaterials from waste toner powder. Characterization techniques reveal that a structural change happened from Fe3O4 to gamma-Fe2O3 and gamma-Fe2O3 to alpha-Fe2O3 at the calcination temperature of 500 degrees C and 700 degrees C respectively. Consequently, optical (band gap) and magnetic parameters of IO samples were significantly varied. The pigment characteristics of the IO samples were evaluated using Commission Internationale de l'Eclairage (CIE) analysis. IO900 sample has shown good brown-red coloration (L* = 43.11, a* = 13.26 and b* = 5.69) and it also exhibited good stability in acidic and basic conditions. Practical applicability of IO pigments were also tested by mixing with plaster of paris (PP) powder. Further, porous IO samples were also used as catalysts in the reductive degradation of methyl orange (MO) dye in presence of excess sodium borohydride (NaBH4). IO, pre-pared at 900 degrees C exhibited similar to 99.9% reduction efficiency within 40 min. Recycling experiments indicated that IO900 possess good stability up to seven cycles. The present porous IO samples will become potential in pigment and environmental remediation.

Automated summary

This article introduces a simple direct calcination method to prepare porous iron oxide nanomaterials from waste toner powder, and characterization techniques reveal the structural changes at different calcination temperatures. The resulting IO samples show good coloration and environmental remediation effects.