Towards a circular phosphorus economy: A bio-inspired, regenerative adsorbent for ultrafast phosphate recovery from wastewater

The transition to a circular “capture–concentrate–reuse” model for phosphorus is essential for sustainable wastewater treatment, yet achieving ultrafast and regenerative trace phosphate removal is challenging. Inspired by the multi-site binding in phosphate-binding proteins, we engineered alanine-intercalated MnLa-layered double hydroxides (MnLa-Ala-LDHs). This material synergistically combines redox-active Mn, high-affinity La 3+ , and zwitterionic alanine. It achieved record-breaking trace-phosphate removal—from 1.009 mg/L to 0.0016 mg/L (99.8 % removal) within 5 min, corresponding to an exceptionally high distribution coefficient (Kd) of 2140 L/g. The adsorbent demonstrates exceptional regenerability, retaining >93 % of its initial adsorption capacity over 10 consecutive adsorption-desorption cycles, while enabling ∼98.5 % recovery of the captured phosphate into a concentrated stream for reuse. Mechanistic studies confirm a synergistic adsorption mechanism and high anion selectivity. This work provides a scalable, bio-inspired adsorbent that serves as both an ultra-deep phosphate scavenger and a regenerable nutrient concentrate, advancing the circular phosphorus economy.