Synthesis of magnetic adsorbents from bamboo fiber functionalized with ferrite–SiO2-PEI for efficient dye removal in wastewater treatment

Abstract

Consistent with the growing concern over dye pollution, this study reports the successful synthesis of CuFe₂O₄ and NiFe₂O₄ via the sol–gel method, followed by silica coating and surface modification with polyethyleneimine (PEI). Magnetic bamboo fiber composites (MBF) were created by effectively depositing CuFe₂O₄–SiO₂-PEI and NiFe₂O₄–SiO₂-PEI on bamboo fibers. The resulting MBF-Cu and MBF-Ni demonstrated improved surface functionality, strong thermal stability, and soft magnetic properties, making them suitable for use as filters for removing dye pollutants from industrial wastewater. The MBF-Ni composite was applied as a fixed-bed column for dye removal, demonstrating excellent performance in eliminating Congo Red (CR) compared with Methylene Blue (MB) and Methyl Orange (MO). The MBF-Ni filter effectively removed CR at a concentration of 10 mg L⁻¹ with removal efficiency and adsorption capacity reaching 90.90% and 2.56 mg g⁻¹, respectively. In addition, MBF-Ni has shown adsorption follows pseudo-second-order kinetics with k₂ = 0.0297 (min) and q_e at 5.83 (mg g⁻¹). Overall, MBF-Ni presents a promising, eco-friendly material for the efficient removal of dye pollutants from industrial wastewater, offering potential for broad-scale filtration and environmental applications.