Selective and effective adsorption of cesium ions by metal hexacyanoferrates (MHCF, M = Cu, Co, Ni) modified chitosan fibrous biosorbent

Abstract

Selective and effective adsorptive removal of radiocesium is of great importance in terms of nuclear waste management and environmental remediation, but is still challenging because of its radioactive and non-complexing nature. Herein, metal hexacyanoferrates (MHCF, M = Cu, Co, or Ni) modified fibrous chitosan was prepared by multiple sequential adsorption and self-assembly approach, and applied for the selective and effective adsorption of Cs+. The physically supported MHCF in chitosan fibers showed good crystallinity and stability, and the obtained fibrous composite has high specific surface area (18.2–29.4 m2 g−1). Moreover, MHCF crystals endowed the fibrous chitosan-based adsorbent with a high adsorption capacity and selectivity towards Cs+. Its adsorption kinetic and isotherm performance followed the pseudo second-order model and the Sips model. The qm value of three fibrous MHCF/chitosan (M = Cu, Co, or Ni) composites was 24.9–70.3 mg g−1. The fibrous CuHCF/chitosan composite had the highest qm among the three composites. In summary, the modified chitosan can selectively and effectively remove Cs+ from complicated aqueous solutions.