The mechanism of sulfur component in pyrolyzed char from waste tire on the elemental mercury removal

A kind of cost-saving pyrolyzed char from waste tire was investigated in the capture of gas phase elemental mercury in presence of O-2. Various pyrolysis/testing temperatures and acid treatment methods were introduced to evaluate their effects on Hg-0 removal by the char. Textural characteristics, elemental contents and surface functional groups analysis were also measured using nitrogen adsorption, scanning electron microscope (SEM), elemental analysis, Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES) and X-ray photoelectron spectroscopy (XPS), respectively. The waste tire char pyrolyzed at 600 degrees C was demonstrated to be a promising gas phase mercury adsorbent when compared with commercial activated carbon. Acid treatment decreased the Hg-0 removal efficiency of the char because of the loss of sulfide from the surface. It indicated that the mechanism of Hg-0 removal by the char was mainly chemisorption and the sulfide groups on the surface served as active cites for Hg-0 removal. The main reaction rout for the Hg-0 removal was assumed that ZnS on the surface of the char reacted with O-2 to form S first, and then Hg-0 reacted with S to form HgS. (C) 2015 Elsevier B.V. All rights reserved.