Adsorption of SO₂ and chlorobenzene on activated carbon

Activated carbon is very effective for simultaneous removal of multiple pollutants. The adsorption of SO₂ and chlorobenzene modeling of VOCs on activated carbon was investigated in a fixed-bed reactor by four kinds of activated carbon. The results show that the SO₂ adsorption is affected by the BET surface and basic functional groups as C=O and π–π* groups of the carbon, while the chlorobenzene adsorption is strongly affected by the carbon pore structure, with the micropore volume deciding the adsorption amount and larger pores increasing the adsorption rate. The chlorobenzene adsorption is little affected by the chemical properties of activated carbon as the O/C ratio detected by XPS. The effect of SO₂ on the chlorobenzene adsorption was investigated, with the results showing the SO₂ seriously restricts the individual chlorobenzene adsorption and this effect becomes smaller in the presence of O₂. The adsorption products were analyzed by TPD-MS and the initial decomposition temperatures are 380 K for chlorobenzene and 500 K for SO₂, showing that SO₂ is much more stable adsorbed than chlorobenzene. The changes of the carbon functional groups that the CO₂ desorption peak emerges at 700 K and decreases at 1000 K with the chlorobenzene adsorption, were observed by TPD-MS, indicating that the lactone and quinone groups on the carbon are likely to combine with the chlorobenzene and form weakly chemisorbed chlorobenzene.