Preparation of phosphorylated conjugated microporous organic polymers and extraction of low-concentration rare earth elements

¹ College of Chemical Engineering, Inner Mongolia University of Technology, Hohhot, 010051, China
² CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China

^a Corresponding author’s e-mail: miyacetx@163.com
^b Corresponding author’s e-mail: mrong@ipe.ac.cn
^c Corresponding author’s e-mail: lryang@ipe.ac.cn

Abstract

Aiming at the extraction and recovery of rare earth elements (REEs) in low-concentration rare earth leaching tailings, a kind of phosphorylated conjugated microporous organic polymer (P-CMP) was prepared and applied to adsorb rare earth ions (Nd³⁺, Dy³⁺, Y³⁺). The structure of P-CMP was characterized by FT-IR. SEM and EDS were utilized to illustrate the surface morphology and element distribution of P-CMP, respectively.The adsorption mechanism of P-CMP was determined by XPS. The effects of pH, ion concentration and adsorption time on adsorption capacity were investigated. The isotherm of the rare earth adsorption process was fitted by Langmuir and Freundlich models, and the kinetics was fitted by Pseudo-firstorder and Pseudo-second-order. The results show that P-CMP is an amorphous microporous material, which has strong interaction with Nd³⁺ (30.18 mg/g), Dy³⁺ (37.84 mg/g) and Y³⁺ (22.01 mg/g), and the synergistic effect of amino and phosphate groups provides good selectivity (S.F.(Nd³⁺/Meⁿ⁺) = 5*10³~5*10⁴). The PCMP selectively adsorbs rare earth ions in the actual system and cycles 8 times.