Browsing by Author "Lisă, Gabriela"

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    ADSORPTION OF LANTHANIDE (III) CATIONS ON CROSS-LINKED IONIC POLYMER, COMPOSITION AND THERMAL ANALYSIS OF THE FORMED COMPOSITES
    (2021) Guțanu, Vasile; Lisă, Gabriela; Rusu, Daniela
    The adsorption of lanthanide(III) cations by a strongly basic cross-linked polymer containing R4N+ groups was studied at 21 and 50°C. At both temperatures the sorption is best described with the Langmuir model. The maximum adsorption at both 21 and at 50°C increases in the series: La3+ < Eu3+ < Nd3+ < Er3+. The results show that polymers containing strongly basic groups can, under certain conditions, be used to separate lanthanide(III) cations in solutions containing mono- and bivalent cations. SEM EDX studies show that La3+, Nd3+, Eu3+ and Er3+ form composites in the polymer phase. The elemental composition of structural units of the composites is La1Cl13.7S64.3O287.7N122.6C2869, Nd1Cl27.4S50.7O391.6N169.3C2896, Eu1Cl8.5S50.8O285N130C2118 and Er1Cl36.8S263.9O1106N447C8657. The thermodynamic parameters of the sorption process are calculated: free energy, enthalpy, and entropy. Thermogravimetric analysis made it possible to determine the stability of the formed composites, the stages of their decomposition and the corresponding kinetic parameters.