Biosorption of Basic Red 18 dye by Aspergillus westerdijkiae ATCC 3174 and Aspergillus ochraceus: optimization, kinetics, and thermodynamic studies

This investigation assessed the adsorption capacities of Aspergillus westerdijkiae ATCC 3174 (AW) and Aspergillus ochraceus (AO) for Basic Red 18 (BR18). Characterization was performed using Scanning Electron Microscopy (SEM) and Fourier Transformer Infrared Spectroscopy (FTIR) techniques. Optimal sorption conditions were identified by adjusting various factors. The biosorption data were analyzed using various isotherm models. The biosorption data were analyzed, and the Langmuir model showed superior fitting to the sorption data for AO based on R² values, while the Temkin model provided a better fit for AW. The biosorption processes followed pseudo-second-order rate kinetics. The maximum biosorption capacity was found to be 11.95 mg/g for AW and 73.53 mg/g for AO. Thermodynamic variables related to biosorption were assessed, indicating that the dye uptake by Aspergillus westerdijkiae and Aspergillus ochraceus occurred spontaneously and was exothermic.