With
the continuous exploitation of arsenic-containing resources
and growing concern over arsenic contamination, the disposal of arsenic
has become a global challenge. Elemental arsenic, because of its
nontoxic nature, is considered a preferred form for arsenic detoxification
and mitigation. We introduce an innovative and eco-friendly method
to convert the highly toxic arsenic trioxide into nonpoisonous elemental
arsenic via a mechanochemical processing at room temperature. Utilizing
zinc powder as the reductant and acetic acid as the reaction medium,
we achieved a remarkable reduction efficiency of 92.5%, producing
elemental arsenic of approximately 99% purity. Thermodynamic analysis
revealed the pivotal role of acetic acid in stabilizing the reaction
system and eliminating the formation of arsine. Density functional
theory calculations further confirmed that the reduction of H3AsO3 on the zinc surface was the dominant reaction
in the Zn–CH3COOH–As2O3 system. The introduction of mechanical force lowered the relative
energy of the reaction, resulting in superior reduction performance
under relatively mild conditions. These findings could pave the way
for the safe disposal of arsenic-containing waste and offer a sustainable
route to reducing the toxicity of arsenic trioxide.