Efficient removal of lead ion from aqueous solution by β-Cyclodextrin modified magnetic sludge biochar

To address the contamination of water bodies by heavy metal, β-cyclodextrin modified magnetic sludge biochar (β-CD@MBC) was synthesized from urban sludge via a chemical co-precipitation method for removing Pb 2 ⁺ from aqueous solution. The structural and morphological characteristics of the material were analyzed using various characterization techniques, and the adsorption performance for Pb 2 ⁺ was evaluated through single-factor experiments. Results indicated an increase in the number of surface functional groups in β-CD@MBC compared to the original sludge biochar (BC) and magnetic sludge biochar (MBC). Both pseudo-second-order and Langmuir models effectively described the remova l process. The actual maximum adsorption capacity of β-CD@MBC at 298 K reached 444.96 mg/g, significantly higher than that of the BC (71.82 mg/g) and MBC (172.32 mg/g). Thermodynamic suggested that the remova l reactions were a spontaneous endothermic process. The removal of Pb 2 ⁺ by β–CD@MBC was influenced by the combined effects of complexation, electrostatic interactions, cation-π interactions, and co-precipitation. After five desorption cycles, the Pb 2 ⁺ removal capacity of β-CD@MBC for 100 mg/L Pb 2 ⁺ decreased by 17.29%, which was lower than that of BC (71.53%) and MBC (39.80%). These results suggested that β-CD@MBC held significant potential for removing Pb 2+ .