Magnetically recoverable, non-toxic, leach resistant aluminum ferrite (AlFeO3) photocatalyst for wastewater remediation

Abstract

The practical use of photocatalyst in wastewater treatment is mainly hindered due to the recoverability of the catalyst. This can be addressed by the ferrite-based compounds which enable magnetic recoverability. In this work, Aluminium Ferrite (AlFeO3), a perovskite-based magnetic photocatalyst is successfully synthesized and its photocatalytic performance is tested. For the scale-up feasibility, the material is tested in static polluted water. AlFeO3 shows effective degradation of textile dye pollutants: 99% of Rhodamine B (RhB) in 180 min and 94% of Methyl orange (MO) in 270 min at the static condition, under visible-light illumination. It also exhibits UV photoactivity which implies AlFeO3 is a potential candidate for sunlight-driven wastewater treatment. The degradation rate is increased by 1.5 times when air is bubbled during photocatalysis. The catalyst is magnetically retrieved from the treated water and reused over 5 cycles with only ∼4% efficiency loss. The environmental viability of AlFeO3 is tested for the first time using cell toxicity studies and catalyst leaching in the treated water. The results indicate that more than 90% of L929 fibroblast cells are viable even when incubated with AlFeO3 for 24 h. The negligible trace of Al and Fe presence in the treated water shows that AlFeO3 is also leach resistant. Hence, AlFeO3 is a UV–Visible-light-driven, easy-to-recover, recyclable, and eco-friendly photocatalyst that has the potential for practical use.