A process for the drying of inorganic hydrogels obtained from readily hydrolyzable compounds of the elements Al, Si, Ti, B, La, Zr, Cr, Sn, Th or Mg, and organic hydrogels based on gelatine, albumin or agar agar, from CO2, to give aerogels is easy to carry out industrially, and drying can be effected at from room temperature to 90 DEG C. The resulting aerogels are transparent and have a low bulk density and low thermal conductivity. The aerogels can be used as packing materials for liquid chromatography, as catalyst carriers, as substrates for enzymes and as adsorbents.