(297a) Dirt and Waste As Sources for Resource Recovery Materials

Surface water, groundwater, and wastewater are emerging as potential new sources to bolster supply chains of critical resources [1]. Implementing sustainable—and ideally circular—pathways to recover these resources is an essential strategy to ensure secure supply chains. Membrane separations can offer energy efficiency, but the membranes themselves can also benefit from consideration of circularity in their manufacturing. We report an approach to tuning transport channels in membranes comprised of naturally sourced materials (e.g., exfoliated and restacked vermiculite or montmorillonite, Figure 1) with molecular cross-linkers to control the interlayer spacing, enhance the membrane stability, and manipulate the chemical and electrostatic environment in the channels [2,3]. The as-prepared cross-linked 2D phyllosilicate membranes exhibit ion diffusivities tuned by the length of the selected cross-linking molecule and are effective in separating ions of different valence. Further control over ion transport behavior can be achieved by molecular functionalization of the mineral interlayer surfaces to place functional groups within the transport channel. Using this strategy, we demonstrate separation of monovalent cations.

A second method for membrane-based resource recovery is through the use of photothermally enhanced evaporation [4,5]. Evaporation ponds are widely used in resource recovery operations, such as sourcing of lithium from geothermal brines, and can often represent a bottleneck in production. Accelerating the evaporation rate using membranes integrating biochar and other waste materials can significantly and sustainably increase supplies of critical materials and nutrients, lessening pressure on supply chains while also addressing environmental challenges such as eutrophication.

[1] O. Kazi et al., Adv. Mater. 35 (2023) 2300913.

[2] Z. Xia et al., ACS Nano 16 (2022) 18266.

[3] Y. Liu et al., ACS Appl. Mater. Interfac. 15 (2023) 57144.

[4] H.-C. Yang et al., Adv. Funct. Mater. 33 (2023) 2304580.

[5] S.-L. Wu et al., ACS Appl. Mater. Interfac. 13 (2021) 39513.