AbstractThe adsorption of the three metal ions, copper, cadmium and zinc in single component and multi‐component mixtures in aqueous solutions by lignite is reported. A comparison is made between the single component saturation uptake and the multi‐component uptakes. The isotherms indicate a competitive uptake with copper being preferentially absorbed by the lignite in multi‐component solutions. The isotherms are plotted to obtain the Langmuir constants, the Freundlich constants and the Redlich–Peterson constants. Lignite is shown to possess an affinity for the metal ions which make its use as an adsorbent a possible alternative to the use of more expensive activated