Influence of the presence of humidity on the adsorption of gaseous arsenic species on TiO2 anatase

Abstract

The presence of arsenic in the environment is one of the most severe forms of contamination. To our knowledge, there is extensive literature on the remediation of this contaminant in aqueous phases, but this is scarce in gaseous systems. Human activities such as mining, metallurgy, fossil fuel combustion, and certain natural processes like volcanic eruptions contribute to the presence of this metalloid in the atmosphere. Given that adsorption is a simple, efficient, and cost-effective technology, the aim of this work is to conduct a theoretical study under isoelectric potential conditions to establish affinity values and electronic transfer of arsenic compounds on the stoichiometric (101) surface of TiO₂ anatase.

The study of the adsorption of isolated As atoms reveal a stronger attraction to the dimer, which exhibits dissociation due to the breaking of the As-As bond. Additionally, there is a greater affinity for As₂O₅ oxide and oxidation of As₂O₃, which is particularly interesting due to the higher toxicity of the latter.

Finally, the acidic forms differ in their behavior in the presence or absence of water.