WaterDAO intends to provide a financial gift to the UA Poly-SM Center to expand the utility of the desalination solvent library computationally identified within the publication by Barbosa and Turner,“Computational Assessment of an Amine-Based Solvent Library for High-Salinity Brine Desalination,” Industrial& Engineering Chemistry Research 62, 8033–8041 (2023), in order to accelerate the understanding and commercialization of solvent extraction desalination (SED).

An expanded solvent library would potentially enable preliminary cost and performance comparisons of various solvents (corresponding to different compositions, conditions, and/or concentrations) with traditional desalination process technologies to determine their effectiveness in achieving a step-change in the capability of SED.

This gift is intended to enhance the Poly-SM Center’s ability to identify solvents with favorable chemical profiles (e.g., low vapor pressures, non-fluorinated/non-halogenated compounds, etc.) that can be integrated with traditional reverse-osmosis (RO) membranes to reduce treatment cost, improve energy efficiency (e.g., lower operating temperatures), increase water recovery or a combination thereof.Furthermore, this gift should help the UA Poly-SM Center synthesize promising solvents, which could potentially undergo pilot testing by WaterDAO.

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Desirable societal/environmental benefits from this gift would include the following representative examples:

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Expanded solvent library and screening criteria

The current solvent library generated within the publication mentioned above (Barbosa, 2023) could be expanded further via the screening protocol developed by Barbosa. Furthermore, new screening metrics could be formulated to more precisely predict the expected real-world performance.
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Thermodynamic analyses and simulation of target solvents

The candidate solvents identified by the initial solvent screening protocol could be further analyzed via other thermodynamic approaches, such as large- scale molecular dynamics simulations, molecular-based equations-of-state (e.g., SAFT), computational toxicity analyses, etc.; this would potentially generate more information about solvent performance and provide additional opportunities for experimental benchmarking of the predicted solvent behavior.
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Computational screening to benchmark performance for commercial SED‍

According to the atomistic- and molecular-level screening, the thermodynamic properties of the top solvent candidates could be used to develop a process-level model of the overall SED process. This would include predicted separation performance and energy requirements, which would be useful for evaluating the overall capital and operating expenditures needed to develop a commercial SED process using the prototype solvents.
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Solvent synthesis for laboratory and pilot testing‍

The most promising solvents identified via computations could then be evaluated for scale-up, initially at scales on the order of ~1 L in laboratories at UA, and their performances tested with comparison of results against computational predictions.

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Final Outcomes Report: it is expected that Poly-SM would provide two stewardship reports to WaterDAO: one by December 15, 2023 and one by September 1, 2024. These stewardship reports would nominally include a presentation of the outcomes and a summary of any new knowledge generated by the financial gift (subject to any restrictions imposed by the UA Intellectual Property Policy¹).

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