Copper Adsorption on Lignin for the Removal of Hydrogen Sulfide

• Main Authors: Miroslav Nikolic, Marleny Cáceres Najarro, Ib Johannsen, Joseph Iruthayaraj, Marcel Ceccato, Anders Feilberg
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Molecules
• Subjects: kraft lignin; adsorbent material; biobased materials; copper adsorption; H₂S adsorption; H₂S removal
• Online Access: https://www.mdpi.com/1420-3049/25/23/5577

Lignin is currently an underutilized part of biomass; thus, further research into lignin could benefit both scientific and commercial endeavors. The present study investigated the potential of kraft lignin as a support material for the removal of hydrogen sulfide (H₂S) from gaseous streams, such as biogas. The removal of H₂S was enabled by copper ions that were previously adsorbed on kraft lignin. Copper adsorption was based on two different strategies: either directly on lignin particles or by precipitating lignin from a solution in the presence of copper. The H₂S concentration after the adsorption column was studied using proton-transfer-reaction mass spectrometry, while the mechanisms involved in the H₂S adsorption were studied with X-ray photoelectron spectroscopy. It was determined that elemental sulfur was obtained during the H₂S adsorption in the presence of kraft lignin and the differences relative to the adsorption on porous silica as a control are discussed. For kraft lignin, only a relatively low removal capacity of 2 mg of H₂S per gram was identified, but certain possibilities to increase the removal capacity are discussed.