Effective and selective adsorption of La3+ by a poly-N-isopropylacrylamide phosphoric modified cellulose aerogel

Abstract

The vigorous development of rare earth elements has become particularly important for the recycling and reuse of rare earth waste solutions. We use the specific coordination of the phosphate group and La³⁺ to recover and separate La³⁺ from secondary resources. First of all, cellulose nanocrystals should be phosphorylated by using phosphoric acid in an aqueous medium. Phosphoric acid groups are introduced to the surface of the cellulose nanocrystal, and then poly-N-isopropylacrylamide is introduced for modification. The purpose is to increase the mechanical properties of the material. The material was characterized by scanning electron microscope, transmission electron microscope, Fourier infrared spectroscopy, N₂ adsorption–desorption analysis, and thermogravimetric and static adsorption experiments. The results of the static adsorption experiments show that the maximum adsorption capacity is 92.28 mg g⁻¹ when the pH is 7.0. After recycling the material five times, the material could still have 87.24% of the maximum adsorption capacity.