Mesoporous RF-Xerogels by Facile Hydrothermal Synthesis
Keywords:Mesoporous materials, RF xerogels, hydrothermal process.
Mesoporous resorcinol-formaldehyde (RF) xerogels were difficult to obtain by conventional sol-gel polymerization at atmospheric pressure because the resulting tenuous RF-gel structures tended to shrink or collapse during subsequent hot-air drying. To avoid this problem, costly and energy-intensive supercritical drying and freeze-drying are often used. In this work the main goal was to produce high-quality RF xerogels with good mesoporosity and high surface area by employing a hydrothermal process. The hydrogel synthesis was carried out in an autoclave at elevated temperature and pressure in order to sufficiently strengthen its network structure. The initial reactant ratio was held constant to search for most suitable hydrothermal temperature and initial pH. The experimental results showed that the reaction in the autoclave at 140ºC and initial pH of 6 could successfully produce RF xerogels with good mesoporosity (peaking pore radius rpeak = 2.38 nm), high specific surface area and large pore volume. The hydrothermal process was on the overall relatively simple, low-cost, and less time-consuming compared to the conventional atmospheric method.
Authors who publish with Engineering Journal agree to transfer all copyright rights in and to the above work to the Engineering Journal (EJ)'s Editorial Board so that EJ's Editorial Board shall have the right to publish the work for nonprofit use in any media or form. In return, authors retain: (1) all proprietary rights other than copyright; (2) re-use of all or part of the above paper in their other work; (3) right to reproduce or authorize others to reproduce the above paper for authors' personal use or for company use if the source and EJ's copyright notice is indicated, and if the reproduction is not made for the purpose of sale.