Study on the mechanism of adsorption of dioxins by oxygen-containing functional groups on activated carbon surface

The adsorption behaviors of the model molecule dibenzofuran (DBF) with similar molecule structure and size to dioxins on the activated carbon was elucidated. The activated carbon adsorbent was coconut shell-based. The adsorption experiments were conducted at 120 ℃. The activated carbon samples were modified by nitric acid at 300, 500, and 800 ℃, and their DBF adsorption capacities were compared. The physico-chemical properties of samples were characterized by BET, TPD-MS, elemental analysis, and other instruments. The results demonstrated that nitric acid treatment could inhibit the adsorption of DBF on activated carbon. The DBF adsorption capacity of activated carbon was related to its surface oxygen-containing functional groups. Lactone groups on activated carbon had the biggest influence on the DBF adsorption. Heat treatment reduced the content of surface oxygen-containing functional groups, and improved the adsorption capacity of DBF.