3D lanthanum modified cellulose aerogel based on filter paper with excellent adsorption performance for phosphate

Cellulose aerogels (CA) were widely used in the adsorption field due to high porosity, ultra-light quality, high-proportioned surface area. This article used a 3D La-CA-based adsorbent to improve wastewater eutrophication. Filter paper as cellulose source was applied and lanthanum was doped. Batch adsorption experiments showed that the maximum phosphate adsorption capacity could reach 54.377 mg g⁻¹ (pH = 3.0). At the same time, the leaching of the lanthanum of the adsorbent was negligible, which proves good stability. In particular, the 3D La-CA presented an overall cylindrical monolith and would be easily separated from water compared with the powdery adsorbent. The adsorption performance of La-CA was not significantly affected by the competitive ions (F⁻, SO₄²⁻, Cl⁻, NO₃⁻) and could still maintain 84.8% after 5 cycles. And mechanism analysis suggested that the 3D La-CA had a specific affinity with phosphates, through electrostatic attraction and inner-sphere complexation. In general, these 3D La-doped cellulose aerogels would provide new possibilities for the practical application of adsorbents in phosphate adsorption.