Activated carbon prepared by physical activation of olive stones for the removal of NO2 at ambient temperature

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). NO₂ adsorption was performed for different inlet gas compositions and temperatures. NO₂ may adsorb directly on the oxygenated surface groups, and can also be reduced to NO. Therefore, a second NO₂ molecule adsorbs on the oxygen left on the carbon surface. TPD performed after NO₂ 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. NO₂ reduction into NO decreased with increasing the inlet oxygen concentration. In contrast, a slight decrease in the NO₂ 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 NO₂ removal.