Effect of thin hydrophobic films for toluene adsorption and desorption behavior on activated carbon fiber under dry and humid condition

The tolueneadsorption and desorptionbehavior of bare activatedcarbonfibers (ACFs) and those with a thinhydrophobic coating were studied. ACF surfaces were made hydrophobic by evaporating polydimethylsiloxane (PDMS) on AFCs under atmospheric pressure condition. In the breakthrough curve of bare-ACF for tolueneunderhumid air condition, the roll-up phenomenon towards tolueneadsorption was observed. This was attributed to the substitution of the adsorbed toluene by water on ACF, leading to a rise of outlet concentration above the inlet concentration with a decrease in the amount of adsorbed toluene. Compared to bare-ACF, a superior selectivity and adsorption capacity for toluene was observed on the ACFs coated with PDMS. It is suggested that the PDMS-coating can increase the removal efficiency of ACF for tolueneunderhumid air condition.