Fungal-derived adsorption membrane to capture potentially toxic elements

Abstract

The release of potentially toxic elements (PTEs) including zinc, copper, and cadmium poses a growing threat to global drinking water quality and accessibility, with marginalized communities often facing the greatest exposure and subsequent health risks, especially those near mining sites with elevated PTE concentrations. Traditional methods for PTE removal are often limited by operational complexities and secondary pollutant generation. Membrane adsorption, a promising alternative, integrates filtration and adsorption functionalities for superior removal efficiency. Yet, its widespread adoption in underserved areas is impeded by high production costs, intricate processing, and a scarcity of ecofriendly membrane materials. In response, this study introduces an innovative approach using Pleurotus ostreatus mycelium to prepare entirely bio-based adsorption membranes, specifically targeting PTE contamination from mining activities. The naturally filamentous nature of the mycelium allows for production of a self-standing, porous filtration material, while functional groups present on the cell wall surface contribute to high adsorption capacities compared to other low-cost and biobased materials. Addition of small amounts of tempo-oxidized cellulose nanofibres (TCNFs) enables control over filtration rates and, hence, adsorbate residence time. Membrane adsorption in a dead-end filtration cell using a mycelium membrane with 1 wt% TCNF exhibits excellent PTE removal, with up to 97% removal of copper, as well as 50% and 68% for zinc and cadmium, respectively. This pioneering, bio-based membrane technology offers a promising strategy to address the necessities of marginalized communities for PTE removal with a simple, effective, and environmentally friendly material.