A Thermodynamic Equilibrium Analysis to Determine the Potential Sorbent Materials for the Control of Arsenic Emissions from Combustion Sources

Abstract

Equilibrium analyses are carried out to determine the potential sorbent materials for effective chemisorption of arsenic in combustion systems. Al-, Fe-, Li-, Na-, K-, Be-, Mg-, Ca-based sorbents are found to be effective. Excellent removal of arsenic is achieved in a wide range of temperatures. However, the effectiveness of these sorbents may be reduced when chlorine or sulfur is present in the system. The presence of chlorine in the system greatly reduces the performance of alkali metal and Fe-based sorbents due to the formation of chlorides. The impact of chlorine on alkaline earth metal and Al-based sorbents is found to be less significant. The presence of sulfur reduces the effectiveness of most sorbents due to the formation of sulfates. The only exception is Al-based sorbent. The affinity to adsorb arsenic generally follows the order: Li > K > Na > Al > Ca > Mg > Fe > Be, if there is no chlorine or sulfur in the system. However, the order of effectiveness will be altered if chlorine or sulfur is present in the system. The analyses establish the understanding of how various parameters affect the effectiveness of the sorption process.