Process for pretreating solid material

Process for pre-treating porous material (10) using electrical energy comprises impregnating the material with an easily ionizable gas before the pre-treatment. Preferred Features: The material is treated with the vapor of a liquid or a gas mixture containing an easily ionizable gas and the vapor of a liquid before the pre-treatment. The vapor is water vapor and the easily ionizable gas is argon. Pre-treatment is carried out using a corona discharge (18).