Sorption of Lanthanum(III) and Neodymium(III) from Concentrated Phosphoric Acid by Strongly Acidic Cation Exchange Resin (SQS-6)

The feasibility of using a macroporous strongly acidic cation exchange resin (SQS-6) as an adsorbent for lanthanum(III) and neodymium(III) from phosphoric acid medium, >4.0 M, was administered using batch and column techniques. Different parameters affecting the sorption of these metal ions such as v/m ratio, acid concentration and the metal ion concentration were separately investigated. The results indicated that the sorption process is relatively fast, reaching equilibrium state within 10 min. Influence of temperature on the equilibrium distribution values was also studied to evaluate the changes in standard thermodynamic quantities where the results indicated that the sorption is endothermic and the process is spontaneous associated with increasing the randomness of the system. The adsorption results of the studied metal ions were found to obey Langmuir isotherm model over the entire studied concentration range. The recovery of La(III) and Nd(III) from the loaded resin was performed with 1.0 M citric acid at pH 4.0. The breakthrough capacity of La(III) and Nd(III) was found to be 33.55 and 17.30 mg/g, respectively. The experimental data resulting from column technique were followed Thomas and Yoon-Nelson models.