Influence of the time of synthesis of SBA-15 on its effect as a catalyst reducing toxicant concentration in tobacco smoke
In recent years, SBA-15 has been suggested as an additive for reduction of toxic compounds in tobacco smoke. The structure of this type of materials is strongly dependent on the synthesis conditions. The objective of the present work is to analyze the influence of the time of the hydrothermal treatment on the structure of the obtained SBA-15 and its effect in reducing toxicants of tobacco smoke. SBA-15 were prepared according a well-known procedure and varying the time of synthesis. The materials were characterized by nitrogen adsorption isotherms, scanning electron micrographs (SEM), X-ray powder diffraction (XRD) and apparent density. Thermogravimetry was run on samples before and after hydrothermal treatment. 3R4F tobacco and catalyst mixtures were smoked under ISO 3308:2000 regime. The composition of the total particular matter (TPM) and the gas fraction smoke was quantified by GC-MS and GC-FID, respectively. Increasing the time of the hydrothermal treatment leads to a decrease of the apparent density, and improvement of the adsorption capacity of the materials obtained, as well as marked reductions in the concentration of different toxicants and nicotine in the smoke generated when mixing the catalysts with the 3R4F reference tobacco under ISO conditions. The effect is saturating and times of the hydrothermal treatment longer than 15 h lead to marginal improvements.