Metal organic frameworks (MOFs) based on phosphonates opened great opportunities for new applications in various interdisciplinary domains [1]. Two categories of factors influenced the self-assembly of MOFs based on phosphonates, namely geometric factors and synthetic parameters [2,3]. A series of MOFs based on phosphonate, M-VP and M-Phen-VP (M = Ce, La, Phen = 1,10-phenanthroline, VP = vinylphosphonate) were obtained by hydrothermal reactions in different conditions: room temperature, 75oC, 180oC, at pH 1.5-7 aqueous solutions. The materials were characterized by FTIR, X-ray powder diffraction and thermogravimetric analysis. The samples are characterized by a high degree of crystallinity, judging from the intensity of the peak in the 2θ region 8-9°. Thermogravimetric analysis performed on cerium and lanthane MOF crystals indicate that the compounds are stable up to 360 oC, after which it undergoes degradation corresponding to loss of the organic unit. The obtained materials were further used as adsorbent materials in the removal process of Rare Earth Elements (REE) from aqueous solutions, using atomic emission spectrophotometry. In order to estabilish the maximum adsorption capacity of the studied MOFs and for the interpretation of the results obtained in the equilibrium study, several empirical isotherms were used: Freundlich, Temkin, Langmuir and Dubinin–Radushkevich. The particular parameters for each isotherm and correlation coefficient (R2 ) have been determined.