Preparation of layered double hydroxides intercalated by tartaric acid anion and its application in boron adsorption

Abstract

Based on the exchangeability of anions between the layers of magnesium-based LDHs, LDHs intercalated by tartaric acid anion (TA-LDH) was prepared by co-precipitation method to adsorb boron, and confirmed by XRD and FT-IR that TA had successfully entered the interlayer of LDH. The adsorption kinetics showed that the adsorption efficiency of B was mainly controlled by the chemisorption mechanism. The thermodynamics revealed that the relationship between the equilibrium concentration of B in solution and the adsorption capacity of TA-LDH for B was consistent with the Freundlich model. Cl− or Li+ in solution had little effect on the adsorption of B by TA-LDH, while SO42− had a great effect on that compared with NO3-LDH. Boron adsorption was accomplished through the interaction between the hydroxyl of TA anion in the interlayer and that of B(OH)3 and B(OH)4−. The elution efficiency of TA-LDH was greater than 70% with ammonium chloride used as the eluent. While TA-LDH still maintained a good adsorption capacity after 5 cycles, and the solubility loss efficiencies of Mg2+ in a single adsorption and elution were 1.5% and 5.4%, respectively. Our study can provide a new idea and method for the development and utilization of magnesium resources.