Potential of waste fungal biomass for lead and cadmium removal: Characterization, biosorption kinetic and isotherm studies

In the last decade, different bio-materials have been investigated for ability to remove metals from aqueous solution. In this study, waste fungal biomass (WFB) was evaluated as a biosorbent for the accumulation and removal of lead and cadmium ions. The biomass being investigated was obtained after the production of Ganoderma lucidum fruiting bodies and was made from residues of the fungus and cultivation substrate. Light microscope and field emission scanning electron microscopy were used in the determination of WFB morphology. The surface area and pore size were determined with the Brunauer–Emmett–Teller and Barret–Joyner–Halenda methods, respectively. WFB was used as an adsorbent directly after drying and after the pre-treatment with three different chemical procedures, which increased removal efficiency from 87% and 84% to 93% and 97% for Pb(II) and Cd(II), respectively. The rate of the adsorption fitted well to a pseudo-second-order kinetic model. In addition, the Freundlich adsorption isotherm model was found to fit the experimental data. It was concluded that WFB represents a promising alternative for the removal of lead and cadmium ions from aqueous solutions.