Three-dimensional Mg-Al layered double hydroxide decorated reduced graphene oxide nanocomposite: An efficient adsorbent for the removal of methylene blue and ciprofloxacin

The jeopardy of toxic dyes and antibiotics posed on human health and water ecosystem is escalating day by day. Herein, three-dimensional Mg-Al layered double hydroxide decorated reduced graphene oxide nanocomposite (3D (Mg-Al) LDH/rGO) was engineered and fabricated via a one -pot in -situ hydrothermal strategy. The hierarchical interconnected (Mg-Al) LDH sheets grew on the surface of rGO vertically, forming a continuous 3D porous network on the surface of rGO. The favorable abundant mesoporous structure and increased specific surface area endowed the nanocomposite with high adsorption towards methylene blue (MB) and ciprofloxacin (CIP). The adsorption kinetics fitting results demonstrated that pseudo -second order model fitted both of MB and CIP adsorption processes better. Langmuir and Freundlich model provided better description for MB and CIP adsorption, respectively. The maximum adsorption capacity of MB and CIP estimated from Langmuir model were 487.8 mg/g at 318 K and 775.2 mg/g at 288 K, which outperformed most of the currently-available adsorbents. The relative adsorption mechanism concerned with pi-pi interaction, hydrogen bonds, complexation and porefilling. The macro 3D structure makes it easy to be recycled and the regeneration tests showed that the obtained nanocomposite possess excellent stability.