Activated carbon is a promising sorbent for adsorption removal of polycyclic aromatic hydrocarbons (PAHs) because of its cost effectiveness. The desorption kinetics of two-ring PAHs, naphthalene and acenaphthene, over bituminous coal-based (AC WY ) and coconut shell-based (AC NT ) activated carbons were investigated. The desorption kinetics were studied over the temperature range of 400800 K at different heating rates (820 K/min) using thermogravimetric analysis techniques. The activation energy, pre-exponential factor and the kinetic model for each sorbate-sorbent pair were determined by applying analytical methods to the non-isothermal data. The Johnson-Mehl-Avrami (JMA) rate equation, g(α) = [ln(1-α)] n (in integral form, where α is fractional completion), following the nucleation and growth model was found to best describe the PAHs desorption from both sorbents. Strong molecular sieving effects were found to influence both adsorption capacity and desorption rates. AC WY , with less micropore (< 0.7 nm) volume and more larger pores (0.72 nm) compared to AC NT , favors PAHs adsorption and desorption rates, leading to different values of kinetic exponent (n) and other kinetic parameters. Likewise, the sieving effects favor adsorption and desorption of naphthalene (kinetic diameter: 0.62 nm) over acenaphthene (0.66 nm) for both carbons.