Monodispersed and Organic Amine Modified La(OH) 3 Nanocrystals for Superior Advanced Phosphate Removal.

Advanced phosphate removal is critical for alleviating the serious and widespread aquatic eutrophication, but strongly depends on the development of superior adsorption materials to overcome low chemical affinity and sluggish mass transfer at low phosphate concentrations. Herein, we report the first synthesis of monodispersed and organic amine modified La(OH) 3 nanocrystals for advanced phosphate removal by modulating inner Helmholtz plane (IHP). These OA-La(OH) 3 nanocrystals with positively charged surfaces and abundant exposed La sites exhibited specific affinity toward phosphate, delivering a maximum phosphate adsorption capacity of 168 mg P/g and a wide pH adaptability in a range of 3.0-11.0 as well as a robust anti-interference performance, which far surpassed those of documented phosphate removal materials. The superior phosphate removal performance of OA-La(OH) 3 was attributed to its protonated organic amine in IHP, which enhanced the electrostatic attraction around the adsorbent-solution interface. Impressively, OA-La(OH) 3 could treat ∼5000 and ∼3200 bed volumes of simulated and real phosphate-containing wastewater to below extremely strict standard (0.1 mg/L) in a fixed-bed adsorption mode, exhibiting the great potential for advanced phosphate removal. This study offers a facile modification strategy to improve phosphate removal performance of nanoscale adsorbents, and sheds light on the structure-reactivity relationship of La-based phosphate adsorption materials. This article is protected by copyright. All rights reserved.