Sorption and possible preconcentration of europium and gadolinium ions from aqueous solutions by Mn3O4 nanoparticles

Mn 3 O 4 nanoparticles were prepared by co-precipitation method. The prepared samples had been characterized to find the compositional, structural, and functional properties, by means of EDX, XRD, and FTIR, respectively. The prepared manganese oxide nanoparticles (Mn 3 O 4 NPs) have average crystallite size of 30–35 nm. The effect of different parameters on the uptake of Eu(III) and Gd(III) by Mn 3 O 4 nanoparticles such as pH, initial metal concentration, shaking time, and temperature was examined. The shaking time for both adsorption and desorption was found to be 5 h. The sorption capacities at equilibrium with regards to Eu(III) and Gd(III) were 26.8 and 12.6 mg/g, respectively. Kinetically, the sorption of both elements fitted well to pseudo-second-order model. Sorption equilibrium isotherm obeys more favorably the Langmuir isotherm model. Desorption process of Eu(III) and Gd(III) from Mn 3 O 4 NPs was highly managed using 2.0 M HNO 3 . A preconcentration factor of 70 and 20 was obtained for Gd and Eu, respectively, using 0.1 g of the Mn 3 O 4 nanoparticles.