In Situ Decoration of Selenide on Copper Foam for the Efficient Immobilization of Gaseous Elemental Mercury

Abstract

Mercury emission from industrial activities is a great threat to public health and ecosystems. Developing new strategies and materials to remove mercury still remains a serious task. Herein, selenide-decorated copper foam prepared by a heating-stirring method (Cu-hs) was used as a monolithic mercury adsorption material. The Cu-hs exhibited much better adsorption of elemental mercury (Hg⁰) compared with the selenide-decorated cordierite honeycomb prepared by the same method (Cordierite-hs). Nearly 100% Hg⁰ adsorption efficiency was obtained under a high gaseous hourly space velocity of 6.0 × 10⁴. Excellent Hg⁰ adsorption capacity was obtained in a wide range of reaction temperatures from 40 to 120 °C, suggesting the good adaptability of Cu-hs in different operating conditions. The Cu-hs exhibited high selectivity for Hg⁰ against H₂O and SO₂, which is advantageous for real applications in industrial flue gas. The Hg⁰ adsorption capacity of Cu-hs reached 3743 g/m³, about 14 times higher than the 243 g/m³ of Cordierite-hs. The excellent Hg⁰ adsorption performance of Cu-hs was attributed to the high affinity of the selenium in Cu₂Se for mercury, the homogeneous distribution of Cu₂Se, and the superior fluid characteristics of the Cu foam substrate. The adsorption performance of the spent Cu-hs could be effectively recovered by HCl solution leaching and subsequent reselenization. The utilization of recyclable Cu-hs provides a cost-effective and environmentally friendly method for removing mercury from industrial flue gas.