Mycoremediation of Cd2+ and Pb2+ from Aqueous Media by Dead Biomass of Phialomyces macrosporus

This manuscript deals with the bioremediation of aqueous media containing Cd2+ and Pb2+ by using dead biomass of the fungus Phialomyces macrosporus. This filamentous fungus with 19.1 m2 g−1 of surface area showed promising adsorption results, since more than 80 % of Cd2+ and Pb2+ were removed from synthetic aqueous media. Adsorption isotherms from this fungal biomass were satisfactorily linearized (R2 > 0.95) by the mathematical Langmuir model and maximum adsorption capacities (MAC) were 1.03 × 10−4 and 6.48 × 10−5 mol g−1 for Cd2+ and Pb2+, respectively. In turn, Gibbs free energy variations were about –25 kJ mol−1, thus highlighting predominantly physical adsorptions. Concomitant cations decreased Cd2+ and Pb2+ MAC values by up to 72.6 % and 70.4 %, respectively, although this limitation has been largely circumvented after increasing the amounts of fungal biomass. As an environmental application of the biosorption of Cd2+ and Pb2+ on Phialomyces macrosporus, real chemical laboratory wastewaters were successfully treated with this filamentous fungus, thus meeting the Brazilian legal standards for cadmium (≤ 1.8 × 10−6 mol L−1) and lead (≤ 2.4 × 10−6 mol L−1). Based on these results and considering that the use of Phialomyces macrosporus to adsorb cadmium and lead is being evaluated for the first time, the original contribution of this study was to broaden the understanding of bioremediation mechanisms.