Аннотация
We report the preparation of a low-cost mercury(II) sorbent by immobilizing copper(II) oxide nanoparticles (CuO NPs) onto a porous biogenic substrate derived from Inonotus obliquus (chaga, Ch), an abundant forestry by-product of Betula pendula Roth. The influence of CuO immobilization time on nanoparticle loading was investigated over the range of 6–96 h. CuO loading increased with immobilization time and reached a plateau at 72 h; therefore, the composite prepared at 72 h was selected for subsequent adsorption experiments. Morphological and structural characterization by scanning and transmission electron microscopies, energy-dispersive X-ray spectroscopy, and X-ray diffraction confirmed the uniform distribution of crystalline CuO NPs (∼37 nm) on the porous biomass support. Comparative adsorption experiments showed that the CuO@Ch composite achieved an equilibrium Hg(II) uptake of 2.47 mg g −1 at 25 °C and pH 6.5, outperforming pristine chaga (2.01 mg g −1 ) under the same conditions. Kinetic data were best described by the pseudo-second-order model, with analysis indicating that external diffusion significantly influenced the overall rate. Equilibrium data fitted well to the Langmuir model, supporting monolayer coverage on a relatively homogeneous surface. The thermodynamic parameters derived from van't Hoff analysis indicated that the adsorption process is spontaneous and endothermic. By combining waste-derived porous biomass with nanoscale copper oxide, this study offers a sustainable and functional composite for mercury removal under near-neutral pH conditions.