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Somen-alkyldiamines with thegeneral formulae H2N(CH2)nNH2 (n = 2–5) were intercalated into the layered silicic acid magadiite, from aqueous solution, causing an increase in the original interlayer distance of 1172 pm. The synthetic magadiite and all intercalated compounds were characterized by elemental analysis, infrared vibrational spectroscopy, X-ray diffractometry, 29Si nuclear magnetic resonance in the solid state, thermogravimetry, scanning electron microscopy, surface area and porosity. The intercalation was followed through a batch-wise method at 298±1 K and gave the maximum amounts 3.70, 2.80, 1.75 and 1.18 mmol g−1, for n varying from 2 to 5, respectively. The well characterized magadiite was calorimetrically titrated in a heterogeneous medium, to obtain the thermodynamic data of intercalation at the solid/liquid interface. Linear correlations were obtained for the number of moles intercalated (Nf), th einterlamellar distance (d) and the specific enthalpy (Δinth) values of the interactive process as a function of the number of C atoms of the aliphatic organic chains (nC) for n-alkyldiamine: Nf = (5.36±0.25) − (0.86±0.07)nC, d = (1406.6±1.9) + (20.9±0.5)nC and Δinth = (5.96±0.25) + (0.06±0.01)nC. The basic N guest atom/silanol acidic center interactions inside the host nanospace gallery gave exothermic enthalpies, positive entropies and negative Gibbs free energy values. This set of data suggests the spontaneity of these intercalation reactions.

Synthesized crystalline sodium lamellar kenyaite exchanges the original cation on the surface to yield silanol groups when exposed to hydrochloric acid solution. The silanol groups successfully favour the formation of covalent bonds with the silylating agents 3-aminopropyltriethoxysilane, N-propyldiethylenetrimethoxysilane and bis[3-(triethoxysilyl)propyl]tetrasulfide, after expanding the interlayer distance with polar organic solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF). These new organofunctionalized nanomaterials were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction, carbon and silicon nuclear magnetic resonance in the solid state, surface analysis, porosity, thermogravimetry, electronic scanning and transmission electron microscopies. The amounts of sililyating agents incorporated into the nanospace were 0.60 ¡ 0.02, 0.90 ¡ 0.04 and 0.96 ¡ 0.01 mmol g 21 , by expanding the interlayer distance of 1633 pm for the original polysilicate to 1933, 1847 and 1828 pm for the sequence of anchored nanocompounds. Nuclear magnetic resonance for 13 C and 29 Si nuclei confirmed the covalent attachment of the organosilyl groups inside the inorganic layered structures, as shown by carbon chemical shifts of the pendant organic chains, with distinguishable 3 Q and 4 Q species, followed by 2 T and 3 T species that correspond to the carbon to silicon bond originating from the precursor silylating agents covalently incorporated in the acidic kenyaite structure. These three new synthesized nanomaterials have the ability to remove divalent cations from aqueous solution. The adsorption isotherms were adjusted using a modified Langmuir equation, whose values enable calculation of the equilibrium constants and negative Gibbs free energies. The favourable values corroborate with the cation/basic centre interaction at the solid/liquid interface in a spontaneous process for these three new nanomaterials.

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