Synthesis of Iron-Based Carbon Microspheres with Tobacco Waste Liquid and Waste Iron Residue for Cd(II) Removal from Water and Soil

Herein, a novel magnetic iron-based carbon microsphere was prepared by cohydrothermal treatment of tobacco waste liquid (TWL) and waste iron residue (WIR) to form WIR@TWL. After that, WIR@TWL was coated with sodium polyacrylate (S.P.) to fabricate WIR@TWL@SP, whose removal efficiency for bivalent cadmium (Cd(II)) was studied in water and soil. As a result, WIR@TWL@SP possessed a high Cd(II) removal efficiency, which could reach 98.5% within 2 h. The adsorption process was consistent with the pseudo-second-order kinetic model because of the higher value of adjusted R-2 (0.99). The thermodynamic data showed that the adsorption process was spontaneous (Delta G degrees < 0) and exothermic (Delta H degrees = 32.42 KJ.mol(-1) > 0). Cd(II) removal mechanisms also include cation exchange, electrostatic attraction, hydrogen-bond interaction, and cation-pi interaction. Notably, pot experiments demonstrated that WIR@TWL@SP could effectively reduce Cd absorption by plants in water and soil. Thus, this study offers an effective method for remediating Cd(II)-contaminated water and soil and may have a practical application value.

Automated summary

A novel magnetic iron-based carbon microsphere was prepared by cohydrothermal treatment of tobacco waste liquid (TWL) and waste iron residue (WIR), which showed high efficiency in removing bivalent cadmium (Cd(II)) in water and soil. The adsorption process followed the pseudo-second-order kinetic model, and thermodynamic data indicated spontaneity and exothermicity. Pot experiments demonstrated the material's effectiveness in reducing Cd absorption by plants in both water and soil, suggesting practical application value for remediating Cd(II)-contaminated environments.