XAD-2 resin modified by nanosecond pulsed discharge to improve the adsorption capacity of polycyclic aromatic hydrocarbons

Abstract

Abstract In this study, nanosecond pulsed discharge plasma is employed to treat the XAD-2 resins in the purpose of improving its adsorption capacity of polycyclic aromatic hydrocarbons. The discharge images, waveforms of pulse voltage and discharge current, and optical emission spectra are measured to investigate the plasma characteristics. The scanning electron microscopy, N2 adsorption-desorption analysis, Fourier transform infrared spectrum, and x-ray photoelectron spectroscopy are employed to characterize the physical and chemical properties of raw and modified XAD-2 resins. It is found that the adsorption capacity of modified XAD-2 resins for polycyclic aromatic hydrocarbons is obviously improved. The adsorption capacity of XAD-2 resins modified by plasma increased by 70% in 10 min adsorption time under the optimal conditions of 20 min treatment time and artificial air. The reason for the improved adsorption capacity is attributed to the increase of specific surface area, the number of 28–33 nm micro-mesopores, and relative intensity of oxygen-containing functional groups (C=O, C–O, and COOH). The possible mechanism of plasma modification of XAD-2 resin is also proposed.