Statistical approach prediction of the textural properties of TiO2–Al2O3 mixed oxides modified by organic glycol-type polymers

TiO2–Al2O3 mixed oxides with one-to-one molar ratio were synthesized from their isopropoxides under various experimental conditions, by co-precipitation. Polyethylene or polypropylene glycols were used as pore-regulating agents. The effect of concentration and the molecular mass of these agents on the surface area and pore structure of the final solid were studied using a statistical model built from a full 23 factorial experimental design. Within the experimental conditions, the response equations for surface area, cumulative pore volume and mean pore diameter show good agreement with the experimental data. The statistical analysis showed that the amount of polymer was the most important parameter, increasing the surface area and porosity of the final solid. Increase of the polymer molecular weight resulted in reduction of surface area and cumulative pore volume but in an increase of mean pore diameter. The textural differences induced by the different polymers are discussed in terms of the possible action mechanisms.