Phosphate Functionalized Layered Double Hydroxide Decorated Wood Aerogel for Efficient Recovery of La(III)

Under the imperative of a circular economy, the efficient recovery of rare earth elements (Lanthanum) from secondary resources is paramount. To overcome the shortcomings of traditional powder adsorbents, such as easy agglomeration and difficult separation, phosphorylated layered double hydroxides (P-LDH) were prepared and immobilized onto the matrix of delignified wood aerogel (WA) to fabricate phosphorylated layered double hydroxide-modified wood aerogel (P-LDH/WA). By intercalating phosphate anions into the interlayer of LDH, specific La(III) chelating sites were assigned to it. The WA substrate retains the renewability of wood and provides a framework with a hierarchical porous structure that can efficiently load P-LDH nanoparticles. Research has shown that the adsorption process of P-LDH/WA follows PSOKM (R² > 0.992), confirming the dominant role of chemical adsorption. When pH = 7.0, P-LDH/WA exhibits excellent La(III) adsorption performance, which is more in line with the Langmuir model (R² > 0.991). The maximum adsorption capacity reaches 58.26 mg g^-1, significantly better than WA (22.10 mg g^-1), And maintain an adsorption efficiency of 81.3% after 3 regeneration cycles, with reusability. Thermodynamic analysis shows that the adsorption process is spontaneous (ΔG° < 0) and endothermic (for P-LDH/WA, ΔH° = 3.77 kJ/mol), indicating that the adsorption capacity increases with increasing temperature. P-LDH/WA combines high capacity, easy separation, and reusability to efficiently recover lanthanum(III) from secondary resources.