Effect of properties of chemically modified activated carbon and aromatic adsorbate molecule on adsorption from liquid phase

The commercial activated carbon Norit ROW 0,8 Supra was modified in various conditions (heating under vacuum, in ammonia, in ammonia–oxygen atmosphere, oxidation with moist air, and with concentrated nitric acid) in order to differentiate its surface properties. The surface and structure characteristics of the carbon samples were obtained on the basis of different techniques: low-temperature nitrogen adsorption/desorption (77.5 K), Boehm method, decomposition of hydrogen peroxide, and thermogravimetry. The effect of adsorbent and adsorbate properties on adsorption from liquid phase was studied for the chosen organic substances of aromatic character. The isotherms of phenol, 4-nitrophenol and 4-chlorophenol adsorption were measured from aqueous solutions on all carbons. The possible mechanisms of adsorption process and solute interactions with carbon surface were analyzed. The effect of substituent in aromatic ring of adsorbate molecule on the adsorption affinity toward carbon surface was regarded.