Amine functionalized activated carbon fibers as effective structured adsorbents for formaldehyde removal

Activated carbon fibers (ACFs) with surface modified by a diethylene triamine (DETA) are synthesized for the abatement of formaldehyde in gas phase at low concentration. Adsorbents with several DETA loadings were tested and characterized. The amount of DETA deposited on the ACFs surface is shown to diminish the porosity. The influence of the DETA on the adsorption capacity towards formaldehyde is studied via dynamic adsorption experiments. The deposition of 20 wt.% DETA allowed ~ 100-fold increase of adsorption capacity as compared to original ACFs. A Schiff base reaction between the amine groups of DETA and formaldehyde was suggested as the adsorption mechanism. Adsorbent surface chemistry was shown to be more important than its microporous structure for efficient formaldehyde removal.