Activated Carbon Modified by Nanosecond Pulsed Discharge for Polycyclic Aromatic Hydrocarbons Detection

In this paper, a nanosecond pulsed discharge was employed to modify activated carbon (AC) adsorbents for the purpose of detecting gas-phase polycyclic aromatic hydrocarbons (PAHs). The raw and modified AC were characterized by helium ion microscopy, N 2 adsorption/desorption, and X-ray photoelectron spectroscopy. The treatment time, gas composition, and pulse peak voltage of discharge were optimized to improve the adsorption capacity of AC. And the adsorption kinetics of AC was investigated. It is found that the pore structure of AC is changed and the oxygen-containing groups on AC surface are increased after plasma treatment. As a result, the roles of physisorption and chemisorption are promoted, and the adsorption rate of naphthalene is improved by about 10%. More importantly, modified AC adsorbing PAHs obeys Pseudo-first-order model and Langmuir isotherm model, and the corresponding adsorption coefficients are fitted, which contributes to detecting PAHs more accurately. After modified AC enriching, the gas-phase PAHs can be detected with the limit of detections in the range of 20–120 μg/m 3 .