Construction of La(OH)₃@Palygorskite-Aerogel with Enhanced Positive Charge for Ultra-Selective Removal of Phosphorus from Rare Earth Feed Solutions

We have developed a novel aerogel adsorbent by combining La(OH)3-modified palygorskite (La(OH)3@Pal) with a chitosan hydrogel modified with terminal aldehyde polyglycols, aiming to enhance phosphate removal by adjusting the inner Helmholtz plane. The resulting adsorbent (La(OH)3@Pal-aerogel) has positively charged surfaces and numerous exposed La sites, giving it a specific affinity for phosphate and high adsorption capacities for both inorganic phosphate (425.52 mg of P/g) and organic phosphate (405.18 mg of P/g). Kinetic studies show that La(OH)3@Pal-aerogel rapidly adsorbs phosphate, removing 98.5% of inorganic phosphate and 99.86% of organic phosphate within 6 h, demonstrating a higher removal capacity compared to most other reported adsorbents. Impressively, La(OH)3@Pal-aerogel can remove over 90% of phosphorus from the rare earth feed solutions at the Baiyunebo mine, offering the potential for improving the downstream extraction efficiency.