Hydrothermal pre-anchoring and in-situ preparation of Prussian blue analogue-polymeric carbon nitride nanorods hybrid for robust and efficient cesium adsorption

Prussian blue analogues (PBAs) are recognized as effective and selective adsorbents for Cs+, however, they suffered from unsatisfactory post-separation performance and inevitable dissolution loss arising from the small size and inferior water instability. In this study, Zn-PBA nanoparticles were integrated onto polymeric carbon nitride (PCN) nanorods to form PBA-PCN hybrid via hydrothermal pre-anchoring and in-situ growth method. The robust and amino-rich PCN played dual roles in securely anchoring the Zn2+ precursor and attracting Cs+ to the surface. Benefiting from the effects of PCN and in-situ generated PBA, PBA-PCN exhibited boosting post-separation performance and water stability in acid and alkaline solutions, which was attractive in different application scenarios. Moreover, PBA-PCN has been demonstrated to be with high adsorption capacity of 376.41 mg/g and favorable selectivity even in the presence of excessive competitive ions. The experimental results and DFT calculations suggested the adsorption mechanism involving strong incorporation/ion exchange and weak electrostatic attraction. The remarkable adsorption performance along with the satisfactory post-separation performance and water stability made it a promising candidate in Cs+ removal and separation.