Three-dimensional honeycomb-like porous carbon derived from corncob for the removal of heavy metals from water by capacitive deionization.

X F Zhang,P C Su,J Yu,S Q Hao,H C Gao,B Wang,X N Wu,Y H Zang

doi:10.1039/c7ra10689k

Abstract

In this study, porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material. The obtained 3DHPC possesses a hierarchal macroporous and mesoporous structure, and a large accessible specific surface area (952 m2 g−1). Electrochemical tests showed that the 3DHPC electrode exhibited a specific capacitance of 452 F g−1 and good electric conductivity. Moreover, the feasibility of electrosorptive removal of chromium(vi) from an aqueous solution using the 3DHPC electrode was demonstrated. When 1.0 V was applied to a solution containing 30 mg L−1 chromium(vi), the 3DHPC electrode exhibited a higher removal efficiency of 91.58% compared with that in the open circuit condition. This enhanced adsorption results from the improved affinity between chromium(vi) and the electrode under electrochemical assistance involving a non-faradic process. Consequently, the 3DHPC electrode with typical double-layer capacitor behavior is demonstrated to be a favorable electrode material for capacitive deionization.

Highlights

Heavy metals ions, as major components of water pollutants, cause increasing risks to the ecological environment and human health due to their toxicity, pervasiveness, and persistence.[1,2,3] In particular, chromium(VI), which is released from plating waste and tanneries, among other industries, if enriched in the human body, can cause irreversible renal injury, muscular cramp, skeletal deformity, and erythrocyte destruction.[4,5] the effective recovery of chromium(VI) from waste water has become a crucial issue
Porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material
From the TEM image (Fig. S1, Electronic supplementary information (ESI)†), it is obvious that 3DHPC shows a macroporous architecture, which is consistent with the Scanning electron microscopy (SEM) image

Summary

Introduction

As major components of water pollutants, cause increasing risks to the ecological environment and human health due to their toxicity, pervasiveness, and persistence.[1,2,3] In particular, chromium(VI), which is released from plating waste and tanneries, among other industries, if enriched in the human body, can cause irreversible renal injury, muscular cramp, skeletal deformity, and erythrocyte destruction.[4,5] the effective recovery of chromium(VI) from waste water has become a crucial issue. Porous carbon (3DHPC) with a 3D honeycomb-like structure was synthesized from waste biomass corncob via hydrothermal carbonization coupled with KOH activation and investigated as a capacitive deionization (CDI) electrode material. When 1.0 V was applied to a solution containing 30 mg LÀ1 chromium(VI), the 3DHPC electrode exhibited a higher removal efficiency of 91.58% compared with that in the open circuit condition.

Results

Conclusion