The effects of selected process parameters in the biosorption of chromium (VI) ions for wastewater treatment using Aspergillus niger were studied whilst keeping temperature and pH constant. The biosorption capacity was observed to be optimum at 15 h contact time, 2.8 g biomass dose and 200 rpm agitation speed. The Jovanovic isotherm model best represented the biosorption equilibrium data, and the equilibrium biosorption capacity was found to be 0.0574 mg/g. The biosorption kinetics was investigated, and the pseudo-second-order kinetic model gave the best fit concerning the generated biosorption data according to linear regression analysis. Thermodynamic study of the biosorption process ascertained the values of standard thermodynamic parameters, including �Go, �Ho, �So, which helped characterize the biosorption process to be exothermic, physical, and spontaneous. © 2022 The Author(s)