Influence of calcium species on SO2 adsorption capacity of a novel carbonaceous materials and their ANN modeling

Abstract Due to the sulfur dioxide (SO2) negative effects to the environment and human health, its removal is currently of great importance to policy markers and researchers. In this context, the present work had the aim to study the SO2 dynamic adsorption behavior on two activated carbons rich on calcium species. One material prepared directly from peach stone shell (PC) and the other prepared from raw material treated with CaCl2 (PCCa) with the purpose to increase the interaction of sulfur with calcium compounds on the surface and to augment its surface area. The obtained activated carbons were characterized using N2 adsorption at 77 K, IR, XRD and SEM/EDX analysis. PCCa carbon presented the higher adsorption capacity compared with PC material, indicating that the surface area and the increase of calcium groups (Ca(OH)2, CaCO3, CaO) are playing an important role during the adsorption of SO2. Additionally, the results demonstrated that as temperature increases the adsorption capacity decreases. On the other hand, the dynamic studies revealed that the residence time reached at 150 mL min-1 flow-rate was the most efficient for the mass transfer processes. Also, the results demonstrated that the presence of moisture decreases the adsorption capacity due to the presence of water molecules on the adsorbent surface. The dynamic adsorption results were modeled using: the Advection-dispersion model, FANN and the conventional models Thomas and Yan. The results shown that the FANN model was the best to correlate the adsorption breakthrough curves of SO2.