Arsenic contamination of groundwater

Chemistry

Electrochemistry

Photochemistry

Selectivity

Electrode

Pollutant

Organic chemistry

Electron transfer

Catalysis

Metal ions in aqueous solution

Arsenic

Environmental chemistry

Adsorption

Metal

Inorganic chemistry

Chromium

Physical chemistry

Redox

Nature Communications

The removal of highly toxic, ultra-dilute contaminants of concern has been a primary challenge for clean water technologies. Chromium and arsenic are among the most prevalent heavy metal pollutants in urban and agricultural waters, with current separation processes having severe limitations due to lack of molecular selectivity. Here, we report redox-active metallopolymer electrodes for the selective electrochemical removal of chromium and arsenic. An uptake greater than 100 mg Cr/g adsorbent can be achieved electrochemically, with a 99% reversible working capacity, with the bound chromium ions released in the less harmful trivalent form. Furthermore, we study the metallopolymer response during electrochemical modulation by in situ transmission electron microscopy. The underlying mechanisms for molecular selectivity are investigated through electronic structure calculations, indicating a strong charge transfer to the heavy metal oxyanions. Finally, chromium and arsenic are remediated efficiently at concentrations as low as 100 ppb, in the presence of over 200-fold excess competing salts.

Electrochemically-mediated selective capture of heavy metal chromium and arsenic oxyanions from water