Removals of Cu(II), Ni(II), Co(II) and Ag(I) from wastewater and electricity generation by bimetallic thermally regenerative electro-deposition batteries

Abstract

The treatment of heavy metal ions in wastewater is of great significance for protecting the environment and human health. To improve the power density and removal efficiency of thermally regenerative ammonia electro-deposition battery and expand the concentration range of effective wastewater removal, a new method for removing Cu(II), Co(II), Ni(II) and Ag(I) from wastewater while generating high-power electric energy by using waste heat, called bimetallic thermally regenerative electro-deposition battery (B-TREB), was constructed in this work. For Cu(II)-containing wastewater with a wide concentration range of 0.002–0.3 M, the removal efficiency (RE) of Cu/Zn-TREB could reach more than 90%. With the initial concentration of Cu(II) being increased from 0.0005 to 0.3 M, the peak power density was enhanced from 20 to 546 W m−2. Besides, for 0.01 M and 0.1 M Co(II) wastewaters, the REs of Co/Zn-TREB were 85% and 90%, respectively. The RE of Ni/Zn-TREB was 88% for 0.01 M Ni(II) wastewater. These results illustrated that B-TREBs could remove many kinds of heavy metal ions in the wastewaters while maintaining a high removal efficiency of ~90% over a wide concentration range, and the produced high-power electricity could provide energy for further treatment or other uses.