Oxidation of Trivalent Arsenic to Pentavalent Arsenic by Means of a BDD Electrode and Subsequent Precipitation as Scorodite

In order to deposit arsenic residues from copper production in a stable way, the trivalent arsenic must first be xidized to arsenic(V). A well-known but quite expensive method for this is oxidation with hydrogen peroxide. In order to enable the oxidation of arsenic on a large scale in the future, a potentially cheaper method has to be found, which offers the possibility of oxidizing extremely high arsenic concentrations. As a novel alternative, electrochemical oxidation using a boron-doped diamond electrode is investigated. Based on previous work, this paper concentrates on the presence of interfering ions during oxidation. Furthermore, it is shown that the electrochemically xidized arsenic(V) can be precipitated as scorodite. Finally, an economic analysis shows the potential financial benefit of oxidation via BDD electrodes compared to hydrogen peroxide.

Automated summary

In order to deposit arsenic residues from copper production in a stable way, the trivalent arsenic must first be oxidized to arsenic(V). A potentially cheaper method, electrochemical oxidation using a boron-doped diamond electrode, is investigated as a novel alternative for large-scale arsenic oxidation. The presence of interfering ions during oxidation and the precipitation of electrochemically oxidized arsenic(V) as scorodite are addressed in this paper. Additionally, an economic analysis compares the financial benefit of oxidation via BDD electrodes to hydrogen peroxide.