Synthesis of Cu-embedded carbon composites via in situ CNTs growth for efficient liquid iodine capture

This study synthesized Cu@CNTs/C composite adsorbent materials through an in situ growth-carbonization strategy, integrating the structural robustness of carbon nanotubes (CNTs) with the high adsorption activity of metallic copper nanoparticles. The resulting material demonstrates excellent performance in the capture of liquid-phase iodine. At 298 K, the iodine adsorption capacity in an iodine-cyclohexane system (I₂-CYH) was 976 mg g^-1, approximately three times higher than that of pristine Cu-based metal-organic frameworks (Cu-MOF). Furthermore, the adsorption capacity in an iodine-water system (I₂-Water) was 9934.3 mg g^-1. The composite demonstrated significant environmental stability across a broad pH range (2-11) and temperature window (298-333 K). Mechanistic investigations indicate that iodine capture is governed by a synergistic interplay of π-π stacking interactions from CNTs, redox conversion of Cu⁰ to CuI (2Cu⁰ + I₂ → 2CuI; 2Cu⁰ + I₃^- → 2CuI + I^-), and electrostatic attractions. These findings suggest that Cu@CNTs/C composites hold promise as candidates for the efficient removal of radioactive iodine contaminants from liquid media.