PVA/PEI crosslinked electrospun nanofibers with embedded La(OH)₃ nanorod for selective adsorption of high flux low concentration phosphorus

Phosphorus (P) is a limiting element causing eutrophication, and thus, its removal has elicited significant attention in recent years. In this study, a La(OH)₃ embedded nanorod loaded PVA/PEI crosslinked nanofiber membrane (LNPPM) was synthesized for phosphorus removal at a low concentration and under high flux conditions. Comparative tests demonstrated that an LNPPM exhibited a high phosphate adsorption capacity (165.9 mg P/g La) and performed well even under interference with the pH and coexisting ions (Cl⁻, SO₄^2-, NO₃⁻, and F⁻). Through a continuous adsorption test, LNPPM also showed a fast adsorption efficiency with a 73.7% capacity used for C/C₀ = 0.5 under a low concentration and high flux phosphate solution. Fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, SEM-EDS, and high-resolution transmission electron microscopy analyses indicated that the La(OH)₃ nanorod intensively and uniformly embedded into the nanofibers, providing an ideal condition for phosphate adsorption. A mechanistic analysis showed that the ligand exchange played a vital role in the phosphate adsorption of LNPPM. A cost index (capacity/synthesis cost) comparison with typical super phosphate adsorbents also indicated that LNPPM (795 mg P/USD) could be a viable option owing to its simple synthesis procedure, low synthesis cost, and considerable capacity. This technique shows promise for use in most dephosphorization applications.