Thermodynamics and kinetics of biosorption of vanadium with macrofungus (Hypholoma fasciculare) and determination by GFAAS

In the present study, a macrofungus, Hypholoma fasciculare (H. fasciculare), was employed for the biosorption of vanadium from aqueous solutions. The characterization of H. fasciculare was conducted using the FT-IR and SEM-EDS techniques before and after biosorption. The batch experimental parameters that affect the biosorption of vanadium on the macrofungus were optimized. The Langmuir, Freundlich, and D-R isotherms were employed, and it was found that the Langmuir and D-R models best explained the adsorption mechanism. The kinetic and thermodynamic characteristics of the biosorption mechanism were investigated in detail. The Langmuir biosorption capacity was found as 159.7 mg/g. The thermodynamic parameters showed that the biosorption of vanadium on the macrofungus was more feasible by decreasing the temperature and the exothermic character of ΔG°= -20.6 kJ/mol at 293 K and ΔG°= -19.9 kJ/mol at 323 K; ΔH°= -26.9 kJ/mol, ΔS°= -21.8 J/mol.K. The biosorption kinetics of vanadium onto the macrofungus H. fasciculare was best fitted with pseudosecond- order (R²≥0.99). The desorption studies showed that 0.50 M of HNO₃ effectively desorbs vanadium from H. fasciculare.