Investigation of the efficient adsorption performance and adsorption mechanism of 3D composite structure La nanosphere-coated Mn/Fe layered double hydrotalcite on phosphate

Severe water eutrophication due to large releases of phosphorus has become a worldwide environmental problem. Adsorption active sites is less of traditional adsorbents in the phosphorus removal process resulting in low removal efficiency, so the new high-efficiency phosphorus removal adsorbents become an effective way to solve the problem. In this work, quercetin modified MnFe layered double hydrotalcite three-dimensional composites structures encapsulated by lanthanum (La(III)) nanoparticles (QLa@MnFe-LDH) were successfully prepared by a classical hydrothermal method. The results of the adsorption experiments show that La(III) nanosphere-encapsulated MnFe-LDH provides a more adequate binding site for phosphate adsorption. The adsorption performance of QLa@MnFe-LDH for phosphate was outstanding, the maximum adsorption capacity was 346.5 mg/g at 298.15 K, which was 300 % higher than that of MnFe-LDH. Moreover, QLa@MnFe-LDH retained its high adsorption capacity (>315.5 mg/g) over a wide range of pH (4.0 ∼ 7.0). The active sites of the reactions were predicted by Multiwfn and Visual Molecular Dynamics (VMD), and novel visualization studies of weak interactions were applied to theoretical studies. The modified MnFe-LDH encapsulated by La nanospheres has a strong adsorption capacity for phosphate adsorption. Therefore, the modified QLa@MnFe-LDH was expected to become an effective adsorption material for phosphorus removal.