Surface Functionalized Approaches of Dry Mycelium Membranes for Enhanced Lead Removal

Mycelium hyphae are biomanufactured to grow into 3-dimensional porous networks, which presents a promise for developing sustainable filtration membranes. The hyphal surface is decorated with various biomacromolecules and enzymes that facilitate the remediation of toxic contaminants from the surrounding environments. In this study, we explore various approaches to enhance the filtration efficacy of membranes for lead removal by surface functionalizing dried mycelium hyphae.<br/>Firstly, we aim to present the bioadsorption capacity of untreated, dry mycelium membranes as a function of environmental parameters such as lead concentration, pH, and the duration of Pb[II] exposure to mycelium. A thermodynamic investigation for lead adsorption is conducted to estimate the adsorption capacities and the kinetic rate constants of Pb[II] adsorption onto the mycelium network. Secondly, hyphal surfaces' surface-functionalization using phosphate is explored to remediate lead via pH-dependent biomineralization pathways. Stable lead-based salt crystals formed at the hyphal cell wall (biomineralization), synergistically assisted with the bioadsorption of lead ions, especially at high lead concentrations (1500 ppm), showed 42% enhancement in lead remediation efficiency compared to sole bioadsorption. Moreover, crossflow filtration demonstrated a 90% removal of Pb[II] within 30 minutes of filtration, offering the potential for permeate reuse and metal recovery from the retentate.<br/>Lastly, we achieve the uniform functionalization of the hyphal surface in the mycelium network through electrochemical deposition using low-dimensional layered MXene structures. This innovative approach amplifies the surface-to-volume functional area and permeability of filtrate via mycelium membrane. The preliminary results show an 83% increase in the kinetic rate of Pb[II] removal for the hybrid membrane compared to the unfunctionalized mycelium membrane. Ongoing studies aim to determine the mechanisms underpinning Pb[II] adsorption within the hybrid membrane. Harnessing the intrinsic chemical functionalities of mycelium hyphae presents a promising approach for advancing mycelium-based biomaterials. This research explores novel, sustainable alternatives to synthetic microporous filter membranes exhibiting comparable or higher remediation efficiencies.<br/>Keywords: mycelium membrane, biomineralization, biosorption, MXene