Weak interaction strategy enables enhanced selectivity and reusability of arginine-functionalized imprinted aerogel for phosphate adsorption.

Abstract

Efficient phosphate adsorption from eutrophic waters remains challenging, fundamentally due to inherent trade-off in common adsorbents: high-binding energy between adsorbent and phosphate compromises reusability while low-binding energy suppresses selectivity. Herein, an innovative arginine-functionalized imprinted aerogel (AFIA-1:4) was fabricated by click chemistry and imprinting modification for overcoming this trade-off through synergistic weak interactions. Results shown that AFIA-1:4 exhibited high adsorption capacity (Q_max of 40.65 mg/g, 30.44 % higher than phoslock), rapid kinetics (15 min), and broad pH applicability (3-11) at 2 mg P/L solution. Moreover, its selectivity coefficient ranged from 10 to 90 even with 15- to 125-fold excess interfering anions, surpassing common adsorbents. After 10 cycles, AFIA-1:4 still maintained 98.15 % regeneration rate with 99.14 % phosphate desorption. Characterizations and calculations confirmed core roles of multiple hydrogen bonds and shape screening in maintaining selectivity and reusability. These findings advanced development of next-generation of phosphate adsorbents, which contributed to sustainable prevention and management of eutrophication.