The performance of a microporous activated carbon prepared chemically from olive stones for removing Cu(II), Cd(II) and Pb(II) from single and binary aqueous solutions was investigated via the batch technique. The activated carbon sample was characterized using N ₂ adsorption–desorption isotherms, SEM, XRD, FTIR, and Boehm titration. The effect of initial pH and contact time were studied. Adsorption kinetic rates were found to be fast and kinetic experimental data fitted very well the pseudo-second-order equation. The adsorption isotherms fit the Redlich–Peterson model very well and maximum adsorption amounts of single metal ions solutions follow the trend Pb(II) > Cd(II) > Cu(II). The adsorption behavior of binary solution systems shows a relatively high affinity to Cu(II) at the activated carbon surface of the mixture with Cd(II) or Pb(II). An antagonistic competitive adsorption phenomenon was observed. Desorption experiments indicated that about 59.5% of Cu(II) and 23% of Cd(II) were desorbed using a diluted sulfuric acid solution.

Activated carbon was prepared from olive stones by physical activation using water vapor at 750 °C. Textural, morphology and surface chemistry characterizations were achieved (nitrogen adsorption, SEM, FTIR and TPD–MS). NO ₂ adsorption was performed for different inlet gas compositions and temperatures. NO ₂ may adsorb directly on the oxygenated surface groups, and can also be reduced to NO. Therefore, a second NO ₂ molecule adsorbs on the oxygen left on the carbon surface. TPD performed after NO ₂ adsorption showed the presence of various surface groups. The adsorption capacity was about 131 mg/g, which is higher than with several activated carbon prepared from classical lignocellulosic biomass. NO ₂ reduction into NO decreased with increasing the inlet oxygen concentration. In contrast, a slight decrease in the NO ₂ adsorption capacity was observed with increasing temperature. It seems that the activated carbons prepared from olive stones by steam activation could be used as efficient adsorbents for NO ₂ removal.