Separation and preconcentration of lanthanum(III) ion from aqueous solution using Cystoseira barbatula

The biosorption of lanthanum(III) on Cystoseira barbatula for preconcentration?separation has been investigated. The sorbed lanthanum on biosorbent was eluted by using 0.005 M etilen diamin tetra acetic acid (EDTA) and lanthanum was determined by complexing with Arsenazo-III following UV-visible absorption spectrometry. The influences of analytical parameters including amounts of biomass, initial pH of solution, contact time, desorption solution type and concentration, eluent volume, sample volume on the quantitative recoveries of lanthanum were investigated. The effects of alkaline and earth alkaline ions and some transition, lanthanide and actinide ions on the retention of lanthanum on Cystoseira barbatula were also examined. Separation and preconcentration lanthanum from water and soil samples was achieved quantitatively. 5 to 50 fold preconcentration was obtained for sample solution having volume from 100 to 1000 mL. The precision (relative standard deviation %) of the method was 2.86 % for lanthanum at a concentration of 1µg m/L for a series of 10 replicates. The recovery for lanthanum was equal or high 94 percent. The validation of the procedure was performed by the analysis of the certified standard reference soil material (SRM 2709). The presented method was applied to the determination of lanthanum in tap water and soil sample with successfully results. The maximum adsorption capacity is between 24.88-83.96mg/ g according to linearized Freundlich model.