ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Sequestration of supercritical CO₂ by mercury oxide

Kledi Xhaxhiu, Erisa Saraçi, and Klaus Bente

Department of Chemistry, Faculty of Natural Sciences, University of Tirana, Blv. Zog I, 1001, Tirana, Albania

E-mail: kledi.xhaxhiu@unitir.edu.al

Abstract: HgCO₃·2HgO (mercury oxide carbonate), along with partly unreacted reactants, was obtained by exploring the behaviour of the Hg₂Cl₂/HgO binary system in supercritical CO₂ (scCO₂) at 200°C, 22000 kPa in the presence and absence of water, using a self-made laboratory-scale system. The reaction of pure HgO with scCO₂ aimed at the synthesis of HgCO₃ (mercury carbonate), also yielded the same product. Meanwhile, with a small amount of water present in the Hg₂Cl₂/HgO-scCO₂ system, at 200°C, 22000 kPa, the mineral terlinguaite (Hg₄O₂Cl₂) was obtained instead of mercury oxide carbonate. Repeating this reaction under the same conditions, but in the absence of CO₂, again resulted in the synthesis of terlinguaite, leading to the assumption that the scCO₂ had no influence on the synthesis of terlinguaite. This study reveals a new moisture-free laboratory method and conditions for the permanent fixation of CO₂ by HgO. This method bears two benefits: 1) it can be introduced to reduce the Hg content in flue gas and fly ash emitted from coal-burning power plants and municipal waste incinerators; 2) it can contribute to CO₂ mineralisation in montroydite (HgO) geological formations as mercury oxide carbonate.

Keywords: CO2 sequestration – supercritical state – mercury oxide carbonate – permanent fixation – terlinguaite – self-made laboratory-scale system

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-013-0356-2

Chemical Papers 67 (6) 594–600 (2013)