© 2020, Islamic Azad University (IAU).In this research, two biocomposite materials, namely Amberlite IRA-400 Cl resin/A. campestris and Amberlite 4200 Cl resin/A. campestris, were used to perform the biosorption of Brilliant Blue G from aqueous solution. The biosorption of dye was evaluated by using a batch system. In addition, the effect of some physicochemical and kinetic parameters of the medium such as pH, temperature, contact time and initial concentration was determined. In this research, pH (3–11), adsorbent dosage (0.3 g), initial dye concentration (10–150 mg L−1), temperature (298–318 K) and contact time (10–95 min) were investigated. In the 95th minute, biosorption reaches a maximum of 137.18 mg/g at the highest temperature (318 K). Brilliant Blue G biosorption increased for both materials and at pH 11 values reached 149 mg/g on IRA-400 Cl resin/A. campestris and 142 mg/g on IRA-4200 Cl resin/A. campestris. The characterization of adsorbents was done by scanning electron microscopy, element detection X-ray and Fourier transform infrared spectroscopy. The adsorption isotherms were examined for the biosorption process. The Harkins–Jura isotherm shows better fit than the other isotherms for IRA-4200 Cl resin/A. campestris, and the Freundlich isotherm is a better fit in the temperature range studied than the other isotherms for IRA-400 Cl resin/A. campestris biocomposite. Thermodynamic values such as enthalpy, change in entropy and Gibbs free energy were measured, and the biosorption process was found to be spontaneous and endothermic. As a result, IRA-400 Cl resin/A. campestris is a suitable biosorbent and has more typical proximity than IRA-4200 Cl resin/A. campestris biocomposite for biosorption of Brilliant Blue G from aqueous solutions.