LAUSR

Residues after supercritical extraction of hops were chosen as activated bio-carbons precursor. The actual adsorbent was prepared by physical activation of the starting material. Some amount of the activated bio-carbon was divided into two parts. One of them was washed with distilled water, while the other part of the activated bio-carbon was washed first with a 5% solution of HCl and then with distilled water. The activated bio-carbons obtained were subjected to textural characterization and determination of pH and the content of surface oxygen groups. Carbonaceous adsorbents obtained were tested for removal of gas pollutant of acidic character (nitrogen dioxide) and liquid organic (methylene blue) and inorganic (iodine) pollutants. The maximum sorption capacity of the carbonaceous adsorbents towards iodine was 1395 mg/g, while towards methylene blue it was 238 mg/g. The results have shown that physical activation of the residue after supercritical extraction of hops is possible to be used as precursor of activated bio-carbons showing high adsorption capacity towards nitrogen dioxide reaching a maximum of 72.1 mg/g. The effectiveness of nitrogen dioxide removal depends on bio-carbons preparation and the conditions of adsorption.