A filter element formed from at least one flat layer of permeable filter medium alternating with at least one pleated layer in such a way that the resulting channels have an open, especially triangular, cross section, a first group of channels being tightly sealed at one end and a second group of channels being tightly sealed at the other end such that a fluid to be filtered flowing through the filter element from an incident flow side formed by one end face to a discharge side formed by the opposite end face, must pass through one of the layers, and at least one group of channels is filled with adsorbent particles and closed by a gas-permeable fabric disposed over the corresponding end face of the filter element, the fabric pores being smaller than the adsorbent particles.