Recovery of uranium(vi) from aqueous solutions using a modified honeycomb-like porous carbon material

Researchers have focused their attention on environment-friendly adsorption materials to solve the energy shortage problem and guarantee the sustainable development of human society. For that matter, pomelo peel, which is a low-cost and universal biomass waste, can be used as an effective carbon source with a large specific surface area. In this paper, a novel composite adsorbent, consisting of a three-dimensional honeycomb-like porous carbon material and MnO₂ nanowires (HLPC/MnO₂), has been successfully synthesized using alkaline activation followed by a carbonization procedure at high temperatures and in situ growth of MnO₂ nanowires. The as-prepared composite was characterized using XRD, FT-IR, XPS, SEM, TEM and BET. The surface area of the HLPC reached 1147.41 m² g^-1. The results of the adsorption experiments show that the highest adsorption value of the HLPC/MnO₂ composite was 238.09 mg-U per g-adsorbent at pH 5. The thermodynamic and kinetic parameters demonstrate that the removal process correlates well with a Langmuir adsorption isotherm model and pseudo-second-order kinetic model. Thus, the HLPC/MnO₂ composite is an excellent adsorbent for removing uranium(vi) ions from aqueous solutions.