Column dynamic studies for lanthanum(III) and neodymium(III) sorption from concentrated phosphoric acid by strongly acidic cation exchange resin (SQS-6)

Abstract

ABSTRACT In this work, solid-liquid extraction of lanthanum and neodymium ions by column technique from concentrated phosphoric acid solutions using the strongly acidic cation exchange resin was experimentally investigated. Measurements of breakthrough curves were measured as a function of column bed depth, initial metal concentration in the feed solution and flow rate. It was found that the breakthrough and time increased with the increase in bed depth and the total mass adsorbed by La(III) and Nd(III) increased with increasing bed depth. At higher initial metal concentrations, the column is quickly saturated, resulting in shorter breakthrough and exhaustion time. It was observed that with increasing the initial metal concentration from 0.10 to 0.50 g/L, the equilibrium adsorption capacities increase from 9.68 to 27.45 mg/g for La(III) and from 4.57 to 19.43 mg/g for Nd(III). Breakthrough time reaching saturation was increased significantly with a decrease in the flow rate. As the flow rate increased from 1.0 to 4.0 ml/min, the exhaustion time of La(III) and Nd(III) decreased from 135.0 to 40.0 min and from 90.0 to 35.0 min, respectively. The capacity of La(III) and Nd(III) was found to be 33.55 and 17.30 mg/g, respectively. The experimental sorption capacity and the time required for 50% adsorbate breakthrough (τ) are close to those calculated resulting from the Thomas and Yoon-Nelson model. These results indicate that the experimental data obey the Thomas and Yoon-Nelson model.