be used i e all of the substrate materials to be used have according to the invention preferably a particle size of less than 2 u03bcm i e there are no particles present having a larger particle size the method of determination used for this in the framework of the present invention is described below suitable substrate materials that can be used according to the invention are clay materials and activated charcoal mixtures of substrate materials particularly mixtures of clay and activated charcoal are also suitable according to the invention in mixtures of this kind however it is preferred if the activated charcoal is used only in a very small portion preferably in a ratio weight ratio to the clay used of 0 5 5 to 0 5 20 more strongly preferably 1 5 to 1 20 with respect to the titanium component the substrate material is preferably used in the composition according to the invention in a quantity such that a weight ratio substrate material titanium of 1 4 to 4 1 results more strongly preferably 1 2 to 2 1 if clay is used as the substrate material a preferred weight ratio of clay to titanium lies in the range 0 5 to 2 0 1 if activated charcoal is used as the substrate material a preferred and suitable weight ratio of activated charcoal to titanium is 0 01.