Efficient removal of Congo Red Dye using MoS2-modified Mg-Al LDH Nanocomposites for Efficient Wastewater Remediation

Abstract

Recently, 2D materials have gained significant attention for their promising applications in water remediation, attributed to their exceptional structural and chemical properties. The Mg-Al LDH and MoS₂/Mg-Al LDH composites were synthesized using hydrothermal method and applied for the removal of Congo Red dye from wastewater. The Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) confirms the successful formation of Mg-Al LDH hexagonal sheets on the surface of MoS₂ petals like structure, while Fourier Transform Infrared Spectroscopy (FTIR) was employed to investigate the functional group present in each sample. The adsorption efficiency of Mg-Al LDH and MoS₂/Mg-Al LDH composites was 56.2 and 116.41 mg/g. Adsorption studies revealed that the MoS₂/Mg-Al LDH composite exhibited excellent adsorption performance compared to MgAl LDH, with a maximum adsorption capacity of 116.41 mg/g. The adsorption behavior of Congo Red dye onto Mg-Al LDH and MoS₂/Mg-Al composite was better described by the kinetic pseudo 2^nd order model and conformed to the Langmuir isotherm model. The thermodynamics studies reveal that the uptake of Congo Red dye on MoS₂/Mg-Al LDH nanocomposite followed a spontaneous and endothermic process. The superior adsorption capability is due to the electrostatic interaction between Congo Red dye with the MoS₂/Mg-Al LDH composite surface, as well as anion exchange between the Congo Red dye and the composite. These findings suggest that MoS₂/Mg-Al LDH composite is emerging as a superior candidate for practical application in removing dye pollutants from wastewater.