Abstract
The properties of natural crystalline molybdenum disulfide (MoS2) nanopowder were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and elemental mapping. In addition, the Congo red (CR) dye (adsorbate)-MoS2 (adsorbent) relationship was investigated. Moreover, the influence of significant factors including pH, temperature, concentration, and time on the adsorption performance of MoS2 nanopowder was investigated. The MoS2 nanopowder exhibited excellent decolorization property. The adsorption isotherm data were best fitted with the Langmuir model, and the calculated maximum adsorption capacity was 80.64 mg/g at 50 °C. In addition, the pseudo-second-order model well-fitted the adsorption kinetics data. The adsorption was a physical process involving electrostatic attraction and the optimum conditions for CR adsorption were determined by the Taguchi method. The reusability test results proved that MoS2 is economical and can be efficiently employed for environmental remediation.