Mg-coordinated self-assembly of MgO-doped ordered mesoporous carbons for selective recovery of phosphorus from aqueous solutions

Abstract MgO-doped ordered mesoporous carbon (OMC-MgO) was synthesized by evaporation-induced self-assembly (EISA) in one-pot with biomass-derived gallic acid instead of phenolics as carbon precursor, metal ion Mg2+ instead of formaldehyde as cross-linking agent and F127 as template. Mg had dual roles as cross-linking agent to coordinate gallic acid-F127 micelle composites, and as promoter of active sites. With the developed protocol, MgO could be uniformly dispersed throughout the carbon skeleton during calcination at 800 °C without agglomeration. As-prepared OMC-MgO-T800 had a specific surface area of 808 m2/g, a perfectly-ordered mesoporous structure centered at (6–8) nm, and exhibited good performance for phosphorus removal from aqueous solutions with a maximum sorption capacity of 107 mg/g. Electrostatic attraction, ligand exchange, and Lewis acid-base interactions are the main phosphate adsorption mechanisms of the developed MgO-doped OMC adsorbents. The as-prepared mesoporous carbon materials are highly selective for phosphorus adsorption from aqueous streams and are reusable and recyclable. This work proposes a green protocol to synthesize OMC-metal oxide composites that is widely applicable to wastewater treatment and technological areas in catalysis and energy storage.