Removal of hydrogen sulfide from a biogas mimic by using impregnated activated carbon adsorbent

PLoS One. 2019 Feb 12;14(2):e0211713. doi: 10.1371/journal.pone.0211713. eCollection 2019.

Abstract

Adsorption technology has led to the development of promising techniques to purify biogas, i.e., biomethane or biohydrogen. Such techniques mainly depend on the adsorbent ability and operating parameters. This research focused on adsorption technology for upgrading biogas technique by developing a novel adsorbent. The commercial coconut shell activated carbon (CAC) and two types of gases (H2S/N2 and H2S/N2/CO2) were used. CAC was modified by copper sulfate (CuSO4), zinc acetate (ZnAc2), potassium hydroxide (KOH), potassium iodide (KI), and sodium carbonate (Na2CO3) on their surface to increase the selectivity of H2S removal. Commercial H2S adsorbents were soaked in 7 wt.% of impregnated solution for 30 min before drying at 120°C for 24 h. The synthesized adsorbent's physical and chemical properties, including surface morphology, porosity, and structures, were characterized by SEM-EDX, FTIR, XRD, TGA, and BET analyses. For real applications, the modified adsorbents were used in a real-time 0.85 L single-column adsorber unit. The operating parameters for the H2S adsorption in the adsorber unit varied in L/D ratio (0.5-2.5) and feed flow rate (1.5-5.5 L/min) where, also equivalent with a gas hourly space velocity, GHSV (212.4-780.0 hour-1) used. The performances of H2S adsorption were then compared with those of the best adsorbent that can be used for further investigation. Characterization results revealed that the impregnated solution homogeneously covered the adsorbent surface, morphology, and properties (i.e., crystallinity and surface area). BET analysis further shows that the modified adsorbents surface area decreased by up to 96%. Hence, ZnAc2-CAC clarify as the best adsorption capacity ranging within 1.3-1.7 mg H2S/g, whereby the studied extended to adsorption-desorption cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption
  • Biofuels* / analysis
  • Carbon / chemistry*
  • Hydrogen Sulfide*
  • Microscopy, Electron, Scanning

Substances

  • Biofuels
  • Carbon
  • Hydrogen Sulfide

Grants and funding

Initials of the authors who received each award: M.S. Masdar. Grant numbers awarded to each author: DIP-2017-020 from Universiti Kebangsaan Malaysia and KK-2014-043 from Sime Darby Research Sdn Bhd. The full name of each funder: Universiti Kebangsaan Malaysia and Sime Darby Research Sdn Bhd. URL of each funder website Universiti Kebangsaan Malaysia http://www.ukm.my/portal/ms/. Sime Darby Research Sdn Bhd http://www.simedarbyplantation.com/our-businesses/research development/overview. Did the sponsors or funders play any role Yes. Universiti Kebangsaan Malaysia: Analysis services Syahril Anuar Md Rejab and Chew Chien Lye are employed by Sime Darby Research Sdn. Bhd. Sime Darby Research Sdn. Bhd. provided support in the form of salaries for authors SAMR and CCL, and played a role in data collection and analysis. The contents/ finding data of this paper have been checked through the Sime Darby Research Intellectual Properties Committee. As a result, this paper obtained a permission to publish in any related public journal. The specific roles of these authors are articulated in the ‘author contributions’ section.