In this study, the removal of natural and radioactive cobalt(II) from aqueous solutions by a modified brick was presented in a batch system and fixed-bed column system. The brick which is originated from Bangui region (in the Central African Republic) contains metakalinite. By treating the brick with sodium hydroxide at 90°C, metakaolinite was transformed into zeolites. Raw brick and its alkali form were fully characterized by environmental scanning electron microscopy (ESEM), energy-dispersive X-ray spectroscopy (EDS) technique, and X-ray diffraction. Elemental analyses of batch and column solutions were realized by using ICP-AES. Equilibrium adsorption data were fitter with the Redlich- Peterson and Sips models than with the two-parameters adsorption models (Langmuir, Freundlich, and Temkin). However, the studied isotherm was closer to the Langmuir isotherm, suggesting that the adsorption process took place mostly on homogeneous adsorbent surfaces. Batch studies revealed that nearly two balancing ions (Na+) in the sodic brick were replaced by one incoming ion (Co2+) from the solution. The use of alkali brick in fixed-bed column permitted to show the efficiency of this adsorbent for the capture of cobalt(II) from synthetic water even in the presence of competitive metal ions like Pb(II), Cd(II), and Mn(II). These investigations highlighted that alkali brick could be a suitable material for industrial/nuclear cobalt (and heavy metals) depollution.