Material Property Targets to Enable Adsorptive Water Treatment and Resource Recovery Systems

Novel separation technologies are necessary to use Earth's limited resources while maintaining a high standard of living. The availability of potable water is stressed due to contamination with trace elements such as lead (Pb). The demand for lithium (Li) due to vehicle electrification will exceed its supply from primarily brine sources within a decade. Adsorption processes are promising cost-effective solutions to challenging low-concentration separations. Yet, there is a lack of quantitative modeling to assess emerging sorbents, which hinders the translation of novel materials into transformative technologies. This work proposes a generalized multiscale process targeting framework to rapidly screen candidate sorbents and set material property targets to develop adsorptive systems including Pb remediation and Li recovery applications. Langmuir isotherm and sorbent structure-property calculations explicitly link molecular properties, including affinity, saturation capacity, and pore size; device design decisions, including sorbent cross-sectional area and bed length; and system design decisions, including sorbent mass and number of parallel beds. The framework predicts that for Pb removal, there is limited scope to improve materials in isolation; instead, integration of sorbents into devices (e.g., membranes, packed beds) may be the larger barrier to realizing future technologies. Similarly, for Li recovery applications, improved materials processing techniques have the potential to accelerate the process. Moreover, the Li case study demonstrates the utility of the framework based on dimensionless formulas as an easy-to-use tool for the broader membrane science and environmental engineering communities to assess the feasibility of emerging materials to meet process demands. Finally, these dimensionless models are used to identify three distinct regions of relative performance between batch and semicontinuous processes. These results give caution to applying scale-up heuristics outside their valid region, which can lead to under- or overdesign during bottom-up studies from the bench to the process scale. The presented targeting framework bridges a crucial gap between material and technology development by identifying the potential for optimized materials processing and device design techniques to fully utilize the characteristics of emerging materials for sustainable separations of the future.

Automated summary

Novel separation technologies are essential for utilizing Earth's limited resources effectively and maintaining a high standard of living. Adsorption processes offer cost-effective solutions to challenging low-concentration separations. However, the lack of quantitative modeling to assess emerging sorbents is a major obstacle hindering the translation of novel materials into transformative technologies.