Furfuryl alcohol (65% aqueous solution), distilled water andformaldehyde were introduced in a reactor. Once the mixture is homogeneous, tannin extract (5 g) is added and mixed with thehelp of a glass stick. Diethyl ether and p-toluensulfonic acid areadded subsequently and stirring is kept for 10–15 s. Finally, the stirring is stopped and the mixture and the catalyst (strong acid)are allow to act. Since the reactor is thermically isolated, the self-condensation of furfuryl alcohol and the condensation of the tanninextract with the alcohol and formaldehyde take place simulta-neously and exothermically. The evaporation of the boiling solvent(at ca. 35◦C) at the same time causes the expansion of the foam.The product is obtained after 30 s. It is chopped into little piecesand cured for 24 h for eliminating the non-evaporated solvent. Thepills were reduced into powder in order to maximize the contactsurface with the help of a manual blender. Finally, the adsorbentwas washed up for removing any rest of reagent and dry at 60◦Covernight. The conservation of these adsorbents is carried out in ashelled test tube.