Dynamic intercalation of methylene blue in BC-MgFe-HT composite: Unveiling adsorption mechanisms for efficient wastewater treatment

Abstract

Developing efficient and eco-friendly adsorbents for removing dye from wastewater presents a significant challenge. In this study, by combining MgFe-hydrotalcite (MgFe-HT) with bamboo charcoal (BC) we report the synthesis of a composite material named BC-MgFe-HT to achieve rapid and effective adsorption of methylene blue (MB) dye. The novelty of our work lies in the distinctive intercalation arrangement of the MB dye post-adsorption within the BC-MgFe-HT layers, which was quantitatively measured and found to be at an intercalation angle of approximately 44.26° rather than the conventional vertical positioning. This unique phenomenon indicates a dynamic rearrangement of the composite structure upon MB adsorption, significantly enhancing its adsorption capacity and efficiency. Comprehensive characterization of the BC-MgFe-HT composite was performed using the following techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area analysis, and thermogravimetric analysis (TGA). The adsorption studies demonstrated a maximum adsorption capacity of 194.09 mg/g within 20 min, attributed to the composite's high surface area, porous architecture, and dye intercalation capacity. Kinetic studies revealed that the pseudo-second-order (PSO) kinetics model best describes the adsorption process, while the Langmuir isotherm model provided the most accurate fit for the adsorption equilibrium data. These findings offer novel insights into the adsorption mechanisms of MB onto the BC-MgFe-HT composite, highlighting its potential for the design and optimization of composite materials for effective wastewater remediation.