Adsorption of Cadmium from Aqueous Solutions by Edible Mushrooms (Agaricus bisporus and Lentinus edodes)

Fungal organisms can remove heavy metals from aqueous solutions. Macro fungi such as Agaricus bisporus and Lentinus edodes (shiitake), commonly called mushrooms, are edible and are grown commercially. Laboratory batch studies were conducted at room temperature (21 ± 1°C) to determine the potential of these fungal biomasses for adsorption of cadmium from aqueous solutions containing 1 mg/L cadmium. Results from batch studies showed that biomasses prepared from A. bisporus and L. edodes had good potential for removing cadmium from aqueous solutions. The maximum adsorption capacity of A. bisporus and L. edodes for uptake of cadmium from aqueous solutions was 2.08 and 0.716 mg/g, respectively. The equilibrium time for adsorption was found to be 6 and 1 h for A. bisporus and L. edodes, respectively. 68% cadmium removal was achieved with A. bisporus and 45% with L. edodes. The optimum initial pH was found to be 6.0 and 5.0 for A. bisporus and L. edodes, respectively. Isotherm studies suggested that cadmium adsorption by both the mushrooms followed the Freundlich isotherm. Desorption of cadmium from mushrooms by dilute HCl was minimal (19%), but rapid.