Methylene blue removal using black cumin seeds waste: experimental study and molecular dynamic simulation

This study reports a potential valorization of black cumin seed waste (BSW) as a low-cost biosorbent for methylene blue (MB) removal. The developed sample was investigated using operational time) and characterization techniques (transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, pHPZC, and N2 adsorption/desorption isotherms). The pseudo-second-order and the Langmuir equations were the best-fitted models to indicate the uptake of MB dye, with an adsorption efficiency of 346.1 mg/g at 20 degrees C. The thermodynamic results suggest that MB adsorption on BSW was favorable, spontaneous, and exothermic. The statistical physics model was used to determine the adsorption mechanism of MB onto the sample BSW. Additionally, the interaction between the MB molecules and the BSW was examined using the Monte Carlo simulation method. The adsorption energy of MB onto BSW was - 19.0 (kcal/ mol), indicating the potential of the adsorbant toward MB dye. The primary mechanisms governing the adsorption process were hypothesized to be electrostatic attraction, van der Waals forces, and hydrogen bonding. Overall, BSW demonstrated promising potential as an alternative low-cost biosorbent for the efficient removal of MB dye from wastewater.