Structural insight into the alginate derived nano-La(OH)3/porous carbon composites for highly selective adsorption of phosphate.

In this study, a novel nano-La(OH)3/porous carbon composites derived from La alginate xerogel with egg-box structure had been successfully synthesized by a gradient heat treatment in nitrogen atmosphere. This facile fabrication strategy can be easily employed to considerably encapsulate La(OH)3 nanoparticles uniformly into the porous carbon matrix derived from the alginate macromolecule framework. The optimized sample, labeled as LS-550(N), exhibited extremely high phosphate uptake and great selectivity. The adsorption kinetic process dramatically followed pseudo-second-order model. The Langmuir model fitted maximum equilibrium adsorption capacity is 133.58 mg·g-1. The phosphate adsorption mechanisms could be consist of electrostatic interaction, complexation and ligand exchange interaction on the surface of LS-550(N). The prominent practical applicability of LS-550(N) in the regeneration test suggests that the LS-550(N) could be a potential adsorption candidate for the decontamination of phosphate-containing natural water bodies.