Waste-cleaning waste: synthesis of ZnO porous nano-sheets from batteries for dye degradation.

This paper describes a clean approach of waste-cleaning waste. Two-dimensional (2D) ZnO porous nano-sheets were synthesized from end-of-life zinc-carbon batteries via a simple homogeneous precipitation-calcination route, and the as-synthesized product was applied as photocatalyst for the purpose of photodegradation of methylene blue/MB aqueous solution under UV-Vis irradiation. Precipitation at ambient temperature resulted in the formation of the crystalline phase of zinc hydroxide nitrate hydrate [Zn5 (OH)8 (NO3 )2 (H2 O)2 ], which was then transformed to ZnO through calcination. FE-SEM studies revealed the resulting ZnO had the morphology of porous nano-sheets with thickness of up to 100 nm. The photocatalytic activity tests proved that the batteries-derived ZnO porous nano-sheets can be a promising candidate for photodegradation of organic pollutant in industrial waste water. The results presented here confirm a possibility of utilization waste batteries as a resource of photodegrading MB in wastewater treatment, hereby an opportunity to deliver environmental benefits. Graphical abstract.