Converting waste magnesium scrap into anion-sorptionable nanomaterials: synthesis and characterization of an Mg–Al–Cl hydrotalcite-like compound by hydrolysis and chemical conversion treatment in aqueous chloride solutions

Abstract

Although there have been many reports on the synthesis of hydrotalcite-like compounds (HTlc), none of them have investigated the special case of converting metal waste into anion-sorptionable HTlc. Mg–Al alloy is the most commonly used Mg alloy. Most metallic Mg waste and post-consumer Mg products are, however, currently not recyclable, thus leaving the resources wasted. Here, methods that allow the reuse and recycling of Mg waste are demonstrated, employing a combination of hydrolysis and chemical conversion treatment in chloride acidic solutions that corrode metallic waste to develop Mg–Al–Cl HTlc. The study can convert bulk-type magnesium waste into nanosized Mg–Al–Cl HTlc powder. For fine flake-type magnesium waste, Mg–Al–Cl HTlc film can directly form on the surface of the flake. All the synthesized HTlcs have nanosized microstructures, being able to function to take up most of the fluoride and sulfate anions from waste water.