Simultaneous Heavy‐Metal Ion Adsorption and Electricity Generation From Wastewater via “Heavy‐Metal Removal Batteries”

Abstract The heavy‐metal ion in wastewater is a great threat to the health of both humans and ecosystems. The common heavy‐metal ion removal strategies usually suffer from energy consumption and poor recyclability. Herein, a heavy‐metal removal battery is designed by constructing a two‐chamber configuration. Such battery displays the capacity of simultaneous heavy‐metal ion adsorption and electricity output, where heavy‐metal ion adsorption is driven by the potential difference between adsorption electrodes and metal electrodes, and electricity is generated continuously during the adsorption process. Significantly, various heavy‐metal ions (e.g., Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, Cr³⁺ and Pb²⁺ ions) can be removed due to the large lattice spacing of active materials in adsorption electrodes, displaying the universality of adsorbing heavy‐metal ions from wastewater. In addition, an environmental‐friendly chemical oxidation strategy is developed to desorb heavy‐metal ions from adsorption electrodes, which not only produces high‐quality metal salts, but also reduces the toxicity of sludge in the case of secondary pollution. Impressively, these heavy‐metal removal batteries can be easily scaled up and integrated to extend the heavy‐metal ion adsorption ability and voltage/current output. This work proves a creative approach for simultaneous heavy‐metal ion removal and electricity generation from wastewater.