Optimisation of critical parameters during alginate aerogels' production

• Formation of alginate aerogels in various alcohols was investigated and optimized
• Alginate with highest viscosity provided aerogels with the highest surface area
• Gelation time had no influence on the surface area but increased pore volume
• Alginate aerogels with largest surface area was obtained by gelation in methanol

A new method – ethanol-induced gelation seems a promising method for preparing gels from various polysaccharides. Anyhow, the characteristics of alginate aerogel, prepared by this method are not the best and the process parameters should thus be optimized. In this research we investigated the effect of process variables, such as the viscosity of alginate, gelation time and type of primary alcohol, on the characteristic properties of prepared materials. Three types of alginic acid were used during the research. The gelation times were set at 1 h and 24 h. Methanol, ethanol, propanol and n-butanol were used for the gelation. The best characteristics of alginate aerogels were obtained by the 24 h gelation time and by using high-viscosity alginic acid. Gelation in methanol is the best method as the surface areas of those samples were much higher (370 m2 g− 1) than those prepared in ethanol (180 m2 g− 1). Those samples also provided low thermal conductivity (0.042 Wm− 1 K− 1).