Removal of Cr(VI) from aqueous solutions using MnFe₂O₄–Coffee husk activated carbon composite

Tóm tắt

This work reports the fabrication of MnFe₂O₄-based composite adsorbents (MFO@CF) derived from HNO₃-activated coffee husk biochar via a combination of co-precipitation and hydrothermal methods. The structural and chemical characteristics of the prepared nanocomposites were analyzed using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Batch adsorption experiments were conducted to evaluate the Cr(VI) removal performance under various operational conditions, including solution pH (2÷8), contact time (10÷120 min), and initial Cr(VI) concentration (5÷30 mg·L⁻¹). The findings indicate that the MFO@CF composite exhibited effective Cr(VI) removal, which can be attributed to electrostatic interactions and the presence of functional groups on the composite surface. According to the Langmuir isotherm model, the maximum adsorption capacity of MFO@CF reached 30.45 mg·g⁻¹, demonstrating its potential as an adsorbent for Cr(VI) removal in wastewater treatment applications. The adsorption kinetics followed a pseudo-second-order model, suggesting that chemisorption may be involved in the adsorption process.