Exploring the biosorption of nickel and lead by Fusarium sp. biomass: kinetic, isotherm, and thermodynamic assessment

Abstract

Fungal biomass is a low-cost and sustainable biosorbent used both actively and passively. This study focused on assessing the efficacy of inactivated and dried biomass of Fusarium sp. in adsorbing Ni²⁺ and Pb²⁺ ions from aqueous solutions. The strain underwent sequenced cultivation and was recovered by filtration. Then, the biomass was dried in an oven at 80 ºC and sieved at 0.1 cm mesh. The biosorbent underwent vast characterization, including analysis of the BET surface area, morphology (SEM), chemical composition (XRF and FTIR), thermal behavior (TGA), and surface charge determination (pH-PZC and zeta potential). The biosorption mechanism was elucidated by examining the fit of equilibrium models to the data, encompassing kinetics, isotherm, and thermodynamic analysis. The biosorbent exhibited a neutral charge, a rough surface, a relatively modest surface area, suitable functional groups for adsorption, and thermal stability above 200 °C. Optimal biosorption was achieved at 25 ºC, using 0.05 g of adsorbent per 50 mL of metallic ion solution at an initial concentration ranging from 0.5 to 2. mg.L^-1 and at pH 5.5 for Pb²⁺ and pH 6.5 for Ni²⁺. Biosorption equilibrium was reached after 240 minutes for Ni²⁺ and 1,440 minutes for Pb²⁺. The process was spontaneous, occurring primarily through chemisorption, and capable of remove over 85 % of both metallic ions. These findings underscore the potential of inactive and dry Fusarium sp. biomass (IDFB) as a promising material for the biosorption of Ni²⁺ and Pb²⁺. Thus, it contributes to the wastewater management and development of sustainable biosorbents, supporting the achievement of the Sustainable Development Goals (SDGs) outlined in the 2030 Agenda.