Dispersive and electrokinetic evaluations of alkoxysilane-modified MgO·SiO2 oxide composite and pigment hybrids supported on it

The paper reports on obtaining and characterisation of functionalised oxide system MgO·SiO2. The synthetic oxide system was obtained by the classical precipitation method performed with the use of sodium silicate and a certain magnesium salt. The most important problem was the functionalisation of the systemʹs surface with selected organic compounds. In this study the silane proadhesive compounds containing characteristic functional groups like amino and glicydoxy ones, were used. The MgO·SiO2 surface functionalisation with silanes can be applied as the process preceding adsorption of organic dyes to ensure getting stable hybrid pigments of wide use. The pigment hybrids were obtained with two organic dyes C.I. Acid Yellow 17 (acidic one) and C.I. Basic Blue 9 (basic one). The functionalised MgO·SiO2 systems and pigment hybrids obtained on their basis were thoroughly characterised to determine the yield of functionalisation with silanes and adsorption of the dyes. The characterisation included determination of the dispersion and morphology of the systems (particle size distribution, SEM images), adsorptive properties (BET isotherms) and electrokinetic properties (zeta potential and electrophoretic mobility). The effectiveness of the surface functionalisation and dye adsorption was tested using FT–IR.