A Pilot Study on the Adsorption of Mercury Chloride by Waste-Tire Derived Powdered Activated Carbon

摘要

The emission of mercury (both Hg~0 and HgCl2) from municipal solid waste incinerators could cause severely adverse effects on human health due to the formation of organic mercury (e.g. methyl mercury) through bioaccumulation and magnification. Thus, the removal of mercury from flue gas is crucial for environment protection. This study investigated the removal of mercury chloride from simulated flue gas by powdered activated carbon in pilot-scale adsorption reactor The powdered activated carbon tested in this study was derived from the activation and pyrolysis of waste tires. The pilot-scale tubular adsorption reactor (16cm I.D. x 120cm L) made of stainless steel was originally designed and constructed for this particular study. Mercury chloride was absorbed by KMnO4/H2SO4 solution in two impingers in series and was then analyzed by a Cold Vapor Atomic Absorption Spectrometer (CVAAS). The operating parameters investigated in this study included types of powdered activated carbon, carbon to mercury ratio (C/Hg), and reaction time. Experimental results indicated that the removal efficiency of HgCl2 increased gradually with reaction time and then leveled off as reaction time was higher than thirty minutes. Moreover, the removal efficiency of HgCl2 increased dramatically as the injection of powdered activated carbon increased from 0.1 to 0.3 g/hr (or equivalent to C/Hg of 6,670-20,010). The highest removal efficiency of HgCl2 that can be achieved by the waste-tire derived powdered activated carbon and commercial powdered activated carbon were 86.5% and 98.9%, respectively. The waste-tire derived powdered activated carbon demonstrated similar removal efficiency of HgCl2 as commercial powdered activated carbon.