DOI: https://doi.org/10.55373/mjchem.v25i3.303

Keywords: Magnetic clay composite; adsorption-desorption; reusability; adsorbent stability

Abstract

Reusability of adsorbent has gained significant research interest in the pursuit of sustainable environmental protection. This study aims to investigate the structural and morphological evolution of a dye-loaded magnetic bentonite composite (MBC) and its reusability for dye removal from water over multiple adsorption-desorption cycles. The magnetic susceptibility, structural and morphological properties of the spent magnetic bentonite composite (SMBC) were characterized by using vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) spectroscopy, x-ray powder diffraction (XRD), scanning electron microscopy coupled with energy dispersive x-ray (SEM-EDX) spectrometry and transmission electron microscopy (TEM). Desorption eluents (NaCl, NaOH, HCl, ethanol and deionized water) were used to investigate the dye desorption efficiency from SMBC. The magnetic susceptibility and morphological properties of the regenerated SMBC were also determined. FTIR results and EDX analysis confirmed the adhesion of methylene blue (MB) dye on MBC. The dye-loaded MBC retained its magnetization strength (11.9 emu/g); however, TEM and SEM images showed increasingly loose morphologies. The 0.1 M NaCl eluent recorded the highest desorption efficiency (64%) following three adsorption-desorption cycles. The magnetic strength and adsorption efficiency of the reused MBC (RMBC) were reduced after the third cycle. The desorption experiment could be further optimized for enhanced reusability of SMBC. Harsh conditions (e.g., higher concentration of eluent) may affect the stability of the regenerated adsorbent, thus warranting future research.