Lignin-Derived Porous Carbon Loaded with La(OH)₃ Nanorods for Highly Efficient Removal of Phosphate

Removing phosphate ions from eutrophic waters is of paramount importance; however, the design of low-cost, high-performance adsorbents for phosphorus removal has remained a huge challenge. Herein, we have demonstrated the fabrication of a low-cost, eco-friendly absorbent, LPC@La­(OH)3, by loading lanthanum hydroxide nanorods within lignin-derived porous carbon for superfast and highly efficient phosphorus removal. As-prepared LPC@La­(OH)3 exhibits a high adsorption capacity of 60.24 mg P L–1 and a high lanthanum usage efficiency. Our results show an ultrafast removal of up to 99.5% phosphate in 10 min when the initial concentration is 2 mg P L–1. Moreover, LPC@La­(OH)3 can efficiently reduce the phosphate concentration to meet the below U.S. Environmental Protection Agency limits (50 μg P L–1) for eutrophication prevention. More importantly, it shows a high phosphate absorption ability over the wide range of pH 3–7, in addition to a high adsorption selectivity toward phosphate and high stability during adsorption process. Both the chemical precipitation and the ligand exchange are mainly responsible for the phosphate removal by LPC@La­(OH)3. As-designed lignin-derived, ecofriendly, high-performance LPC@La­(OH)3 shows enormous potential for the phosphate removal from both municipal wastewater and industrial effluents