Adsorption of Mercuric Chloride from Simulated Incinerator Exhaust Gas by Means of Sorbalit^TM Particles

Abstract

In this work the attention was focused on the use of Sorbalit^TM, a mixture of impregnated activated carbon and Ca(OH)₂, for adsorption of mercuric chloride from flue gas of municipal solid waste incinerators. The study was performed in an apparatus at laboratory scale in which simulated flue gas at a given temperature and HgCl₂ concentration flowed through a fixed bed of adsorbent material. The experimental results showed that the adsorbate loading at saturation depends on temperature in an unusual fashion: the saturation adsorbate loading decreases with T for 70° ≤ T ≤ 150°C, but then increases for 150° ≤ T ≤ 250°C. This result was interpreted by assuming that for T ≤ 150°C a process of physical adsorption takes place, while for T ≥ 150°C the results fall in a “transition zone” between physical adsorption and chemical adsorption. The Langmuir parameters were evaluated for the “low” temperature results, and the differential equations modeling the adsorption phenomenon were integrated, leading to the evaluation of a kinetic parameter describing the breakthrough curves experimentally determined.