A colloidal dispersion having carrier particles of silica having a particle size from 3 nm to 100 nm to which silver ions have been adsorbed, preferably in an amount of 0.0005-5 silver ions per nm2 of silica particle surface. The surface of the carrier particles of silica suitably contains aluminumsilicate sites. It also relates to a process for making a colloidal dispersion comprising providing a silica sol, adding a solution of silver nitrate to the silica sol under agitation yielding a colloidal dispersion with silver ions adsorbed on the surface of the silica particles. The dispersion is usable as a biocide in e.g. coatings, adhesives and sealants, in surface treatment and impregnation of organic materials, in surface treatment and impregnation of inorganic materials, in textiles, garments and shoes, in medical disposables, in plastics and rubbers, in water and air purification, and in crop protection.
