Layered mesoporous Mg(OH)2/GO nanosheet composite for efficient removal of water contaminants

Abstract

A layered magnesium hydroxide (Mg(OH)₂) nanosheet/graphene oxide (GO) composite was synthesized through laser ablation of the Mg target in an aqueous solution with GO. Its mesoporous structure and application as an adsorbent for the removal of methylene blue (MB) and heavy metal ions from water were investigated. Mg(OH)₂ nanosheets were organized in situ from the strong reaction between the laser-ablated Mg species and water molecules. The GO nanosheet served as a heterogeneous nucleation and growth site for sheet-like Mg(OH)₂ nanocrystals. The resulting porous Mg(OH)₂/GO nanosheet composite had a high specific surface area of 310.8 m² g⁻¹ and a pore volume of 1.031 cm³ g⁻¹. These characteristics show that the composite could be an excellent adsorbent. The composite exhibited a maximum adsorption capacity of 532 mg g⁻¹ at 298 K for typical contaminants of MB, and over 300 mg g⁻¹ for heavy metal ions Zn²⁺ and Pb²⁺.