Highly-dispersed Fe2O3@C electrode materials for Pb2+ removal by capacitive deionization

Capacitive deionization (CDI) is increasingly being considered as an effective solution for treating heavy-metal contaminated water. Surface modification of electrode materials with metal oxides is the key to yield high specific capacitance of transition metal oxides for enhancing the efficiency of CDI processes. In this study, we proposed a simple and effective strategy to produce a new, well-ordered Fe 2 O 3 @C composite for Pb 2+ removal via CDI technology. Through controlling hydrofluoric acid-inducing solvothermal carbonization , Fe 2 O 3 dots were highly dispersed in carbonized substrates without using traditional high-temperature calcination . The products possessed regular octahedral morphology with a uniform distribution of α-Fe 2 O 3 in nearly quantum scale (∼20 nm) throughout the carbon matrixes. Compared with other similar materials, the well-dispersed Fe 2 O 3 in carbon matrixes significantly increased the surface areas (∼1832 m 2  g −1 ) and specific capacitance (115.6 F g −1 ) of Fe 2 O 3 @C composites. Using the composites as electrodes, the Pb 2+ adsorption capacity reached 830.17 mg g −1 , which is 28% higher than reported materials. Furthermore, the composites electrode possess a high regeneration efficiency, after 10 cycles, 90.3% of the initial performance is still retained. Our study demonstrated great potential of the novel Fe 2 O 3 @C composites for the removal of heavy metal ions using CDI processes.