Adsorption-oxidation of hydrogen sulfide on Fe/walnut-shell activated carbon surface modified by NH3-plasma

Walnut-shell activated carbon (WSAC) supported ferric oxide was modified by non-thermal plasma (NTP), and the removal efficiency for hydrogen sulfide over Fe/WSAC modified by dielectric barrier discharge (DBD) was significantly promoted. The sample modified for 10 min and 6.8 kV output (30 V input voltage) maintained 100% H2S conversion over a long reaction time of 390 min. The surface properties of adsorbents modified by NTP under different conditions were evaluated by the methods of X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis and in-situ Fourier transforminfrared spectroscopy (FTIR), to help understand the effect of the NTP treatment. NTP treatment enhanced the adsorption capacity of Fe/WSAC, which could due to the formation ofmicro-pores with sizes of 0.4, 0.5 and 0.75 nm. XPS revealed that chemisorbed oxygen changed into lattice oxygen after NTP treatment, and lattice oxygen is beneficial for H2S oxidation. From the in-situ FTIR result, transformation of the reaction path on Fe/WSAC was observed after NTP modification. The research results indicate that NTP is an effectivemethod to improve the surface properties of the Fe/WSAC catalyst for H2S adsorption-oxidation. (C) 2017 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.