Carbon-based electroactive ion exchange materials: Ultrahigh removal efficiency and ion selectivity for rapid removal of Cs plus ions

Radioactive cesium (137Cs) ions exhibit high-energy gamma radiation and long half-life. When they enter water body, serious environmental problems and damage to the human body are always generated. Herein, an electroactive composite membrane was facilely prepared by uniformly deposition of nickel hexacyanoferrate (NiHCF) nanoparticles on the surface and inner wall of coal-based tubular carbon membrane (CTCM) for rapid and selective separation of Cs+ from wastewater. This NiHCF incorporated CTCM tube exhibited an extremely high removal rate (over 99.99%) over a long period. Meanwhile, it also demonstrated extreme Cs+ selectivities even in the solutions with high coexisting ion concentrations (e.g., Cs+:Na+ = 1:99, Cs+:K+ = 1:99). The rapid and selective Cs+ uptake/release should be attributed to the better dispersion of NiHCF nanoparticles with high selectivity to Cs+ in the CTCM tube, which reduced the mass transfer distance, increased fluid turbulence and accelerated mass transfer rate. It is expected that such a NiHCF incorporated CTCM tube could be a promising alternative of conventional materials for the separating of radioactive Cs+ ions.

Automated summary

The electroactive composite membrane with nickel hexacyanoferrate (NiHCF) nanoparticles deposited on coal-based tubular carbon membrane (CTCM) surface and inner wall showed rapid and selective separation of Cs+ from wastewater. The composite membrane demonstrated extremely high removal rate and Cs+ selectivity, even in solutions with high coexisting ion concentrations. This can be attributed to the dispersion of NiHCF nanoparticles with high selectivity to Cs+ in the CTCM tube, which enhances mass transfer rate.