Removal of lithium from water by aminomethylphosphonic acid containing resin

Abstract

This paper gives an overview of the ability of an aminomethyl­phos­phonic acid-containing chelating resin for the removal of lithium from water. The studies were performed under various conditions, such as resin dose, initial Li+ concentration, solution pH and solution temperature. The results showed that the sorption of Li+ reached equilibrium within 15 min and the experimental data were well-fitted by the pseudo-second-order kinetic model. The Li+ sorp­tion was highly pH dependent, and the optimum pH for Li+ removal was ≥3. Isotherm sorption data displayed good correlation with the Langmuir model, and the maximum monolayer sorption capacity of the resin found to be 13.65 mg g-1. Thermodynamic studies suggested that Li+ sorption onto the chelating resin was an exothermic and spontaneous process in nature. The resin could be regenerated by 0.1 M HCl, NaCl or H2SO4 with > 99 % efficiency. Desorption of Li+ with 0.1 M NaCl resulted in no changes in the uptake capacity through four sequential sorption/desorption cycles.