Removing hydrogen sulfide from a feed stream using suitable adsorbent materials

Abstract

A series of materials, including sand (S) silica blue (SB), iron-exchanged sand (IES), zeolite 13X (Z), iron-exchanged zeolites (IEZ), and the waste material acid mine drainage sludge (AMDS), were used as adsorbents for the removal of hydrogen sulfide (H2S) from a feed stream in a pilot (bench)-scale study. Artificially polluted H2S gas streams were created using a gas cylinder with 10,000 ppmv of H2S in nitrogen (N-2), which was used for further dilution. The adsorption performance of each sorbent material was assessed by dynamic breakthrough analysis. The sorbents were analyzed via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-Ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The efficiency of H2S removal was observed and compared between adsorbents under various operating conditions, such as different contact times and initial concentrations. The AMDS was discovered to have highest adsorption efficiency for H2S, of all adsorbents studied here. The Yoon-Nelson, Thomas and Adam-Bohart models were applied to study the effects of H2S concentration and flow rate on adsorption of H2S on AMDS, and the maximum adsorption capacity of 312.73 g g(-1) was attained at 1000 ppmv and 0.5 L min(-1) of H2S concentration and flow rate, respectively. This study found that all tested adsorbent materials have appreciable H2S adsorption capacity and AMDS in particular is an appropriate adsorbent for treatment of H2S-contaminated steam. Moreover, AMDS is a waste material and is available in abundance; hence, AMDS could be a practical choice for the adsorption of H2S from biogas. (C) 2020 Elsevier Ltd. All rights reserved.