Abstract The adsorption capacity of conductive polyaniline doped by thiacalix [4] arene tetrasulfonate (PANI–TCAS) towards Cu (II), Cd (II), Co (II) and Cr (III) was investigated through batch adsorption techniques, and the extent of adsorption was measured as a function of pH, initial metal ion concentration and contact time. It was found that the metal ion removal reached maximum at pH 8.0 and remained constant after 60 min. Experimental data was fitted to Langmuir, Freundlich, Redlich–Peterson and Temkin equation models with ...