Among the effective ways of obtaining the rare-earth metals is their extraction from water with silica-based adsorbents [1]. We synthesised sorbents via the one-pot modified Stöber method using three different structuring agents and functionalizing silanes. Tetraethyl orthosilicate (TEOS), silanes with ethylene (≡Si–C2H4–Si≡) and phenylene bridges (≡Si– C6H4–Si≡) were used as structuring agents. Meanwhile, functionalizing silanes contained diverse amino groups (aminopropyl, diamino and secondary amino). The characteristics and sorption properties of the samples to Eu(IIІ) rare earth metal ions are given in Table 1. Table 1. Composition and characteristics of the samples Structuring silane Functional silane SBET, m2/g Vp, cm3/g N, % wt Cgr, mmol/g pI SSC Eu3+, mmol/g Si(OC2H5)4 –(CH2)3NH2 88 0.26 2.35 1.6 8.8 0.23 ≡Si–C2H4–Si≡ 64 0.11 6.10 4.1 9.4 1.04 ≡Si–C6H4–Si≡ 620 0.43 3.55 2.4 3.7 0.54 Si(OC2H5)4 –(CH2)3NH(CH2)2NH2 427 0.51 7.54 2.9 10.1 0.55 ≡Si–C2H4–Si≡ 147 0.12 6.19 2.4 3.3 0.37 ≡Si–C6H4–Si≡ 190 0.21 7.54 2.9 9.2 0.52 Si(OC2H5)4 =[(CH2)3]2NH 607 0.52 4.29 3.2 4.7 0.67 ≡Si–C2H4–Si≡ 759 0.62 4.28 3.2 4.0 0.66 ≡Si–C6H4–Si≡ 718 0.58 3.65 2.7 2.9 0.63 Generally, the static sorption capacity (SSC) of adsorbents is affected by porosity (accessibility of groups) and functional groups content (Cgr). The structuring agent usually determines the porosity of the materials (e.g. bridging silanes ensures larger specific surface (SBET) values). But the size and charge of the groups also affect the formation of pores (the particles sizes and the spaces between them). For the studied samples, the Eu3+ SSC completely correlates with Cgr. TEOS-based sample with aminopropyl groups has the lowest SSC value, explained by the poor SBET and Cgr in this sample. Comparing the materials with the same Cgr (e.g. 2.4 or 2.9 mmol/g), the higher Eu3+ SSC is observed for the sample with better SBET. Furthermore, samples with a secondary amine group (with high SBET and Cgr ranging from 2.7 to 3.2 mmol/g), demonstrate sufficiently large SSC of 0.63 to 0.67 mmol/g. Thus, analyzing Eu(IIIІ) ions sorption, it can be concluded that Cgr is important to achieve high sorption capacity by adsorbents. However, the well-developed porous structure of the samples and the accessibility of the groups also have a great advantage.