Plasma-induced adsorption of elemental mercury on TiO2 supported metal oxide catalyst at low temperatures

A plasma-catalyst reactor was used for the adsorption of elemental mercury at low temperatures. SiO2, TiO2 and SiO2 or TiO2 supported transition metal oxide catalysts were packed in the plasma discharge zone for adsorption enhancement. The results indicated that non-thermal plasma could induce the adsorption of elemental mercury effectively by catalysts. TiO2 displays much higher adsorption efficiency than SiO2 does. The adsorption efficiency is greatly improved by loading transition metal oxides on TiO2. Mn/TiO2 is the most efficient catalyst, and similar to 99% of Hg-0 adsorption efficiency can be obtained under a SED of 2.3 +/- 0.3J L-1. The interaction between the plasma and catalyst was also investigated. The chemical properties of the catalyst, such as the active sites and electron transfer capacity, are key factors that affect adsorption efficiency. The mercury adsorption in plasma-catalyst reactor results primarily from the interaction between weakly adsorbed mercury and activated oxygen on catalyst surface induced by plasma. In addition, the effect of the O-2 concentration and HCl on mercury adsorption efficiency was investigated. The adsorption efficiency has a logarithmic correlation with O-2 concentration in the gas flow. (C) 2015 Elsevier B.V. All rights reserved.