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

This article mainly demonstrated the promotional impacts of PVP modification on the Hg-0 capture performance of CrOx monometallic oxide. Compared with virgin CrOx, an improvement in the Hg-0 abatement capability was achieved for the PVP-modified CrOx and the amplification of the Hg-0 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 Hg-0. Meanwhile, relying on the strong affinity of -OM to Hg-0 and the increased number of Cr6+ and O-alpha, the adsorbed Hg-0 could be easily transformed to HgO and Hg-OM, which thus enabled PVP-modified CrOx to present an elevated Hg-0 removal performance, particularly at higher temperatures. Throughout the Hg-0 removal cycles, Cr cations with a high valence state and chemisorbed oxygen species played the part of active sites to oxidize Hg-0 to HgO for virgin CrOx, whereas oxygen-containing functional groups were also responsible for the elimination of Hg-0 over the PVP-modified adsorbent.