Highly selective capacitive adsorption and rapid desorption of arsenic ions in wastewater achieving by a recyclable urchin-like iron-manganese composite electrode

Abstract

The demand for environmental protection drives researchers to develop new concepts or technologies to solve the problem of heavy metal pollution in wastewater. Herein, we report recyclable CDI electrodes composed of sea urchin-like iron-manganese composites to explore the capacitive adsorption and selective adsorption effects of arsenic ions in the simulated wastewater. Under the operating conditions of 1 mm electrode spacing and 1.2 V voltage, the maximum saturated adsorption capacity of the composite electrode for arsenic ions reached 411.22 mg/g, and when the initial concentration was 20 mg/L, the removal rate of arsenic ions reached 99.7%. Besides, the composite material also showed an excellent selective adsorption capacity under the coexistence of lead and cadmium ions. Finally, this recyclable composite electrode was capable of rapid desorption and can retain 97% of the initial capacity after fifty cycles of adsorption/desorption.