Promotional effect of PVP-modification on Hg0 removal over CrOx monometallic oxide

Abstract

This article mainly demonstrated the promotional impacts of PVP modification on the Hg0 capture performance of CrOx monometallic oxide. Compared with virgin CrOx, an improvement in the Hg0 abatement capability was achieved for the PVP-modified CrOx and the amplification of the Hg0 removal efficiency became more prominent upon the raise of the reaction temperature. The modification of PVP brought out an increment in the number of the sites with intermediate and strong acidity, somehow aiding the adsorption of Hg0. Meanwhile, relying on the strong affinity of -OM to Hg0 and the increased number of Cr6+ and Oα, the adsorbed Hg0 could be easily transformed to HgO and Hg-OM, which thus enabled PVP-modified CrOx to present an elevated Hg0 removal performance, particularly at higher temperatures. Throughout the Hg0 removal cycles, Cr cations with a high valence state and chemisorbed oxygen species played the part of active sites to oxidize Hg0 to HgO for virgin CrOx, whereas oxygen-containing functional groups were also responsible for the elimination of Hg0 over the PVP-modified adsorbent.