Harnessing dried mycelium membranes for rapid and efficient lead cleanup in soils

Bioremediation offers a sustainable strategy for mitigating heavy metal contamination in soil, but is often constrained by slow removal kinetics, limited uptake efficiency, and high implementation costs. This study investigates dried mycelium membranes, rich in surface-bound proteins and high surface area, as a promising biosorbent for in situ Pb(II) remediation in urban soils. Untreated mycelium membranes buried in soil achieved Pb(II) removal efficiencies of ∼70 % and ∼40 % at initial lead soil concentrations of 100 mg/kg and 1500 mg/kg, respectively, within eight days. Phosphate-functionalized (PF) membranes demonstrated enhanced performance, achieving 70-80 % Pb(II) removal even at high concentrations (1500 mg/kg) and low pH (4.0). Mechanistic analyses revealed that Pb(II) sorption on untreated membranes was primarily electrostatic sorption, whereas PF membranes facilitated both sorption and mineralization of Pb(II) ions, confirmed via infrared spectroscopy and X-ray diffraction. Kinetic modeling showed pseudo-second-order behavior at 100 mg/kg for both membrane types, with remediation rates of 0.2-4.2 E-3 mg g^-1.min^-1. At higher Pb(II) concentrations, PF membranes followed an intraparticle diffusion model, reflecting limited surface sites. Although PF membranes exhibited slower rates compared to untreated ones, a cumulative membrane replacement strategy significantly increased the removal efficiency. Overall, dried mycelium membranes present an eco-friendly alternative, achieving ∼ up to 80 % Pb(II) removal within 8 days, comparable to biochar or chemically amended systems, while uniquely enabling physical retrieval of both the membrane and immobilized lead, thus minimizing long-term environmental risks.