Critical Needs in Separation Science

LCGC North America, LCGC North America-08-01-2020, Volume 38, Issue 8
Pages: 470

A U.S. government-sponsored report released last year puts a spotlight on critical concerns affecting the future of separation science.

In 1987, the National Academies of Sciences published a report titled “Separation and Purification: Critical Needs and Opportunities.” The report was instrumental in highlighting important fundamental challenges in the field of separation science in order for the field to progress. Over that 30-year period, there have been dramatic changes in the field, but there are still a number of important challenges that remain. In 2018, the National Academies of Sciences, Engineering, and Medicine convened a consensus study committee chaired by Joan Brennecke of the University of Texas at Austin and made up of 13 members, including me.The final report, titled “A Research Agenda for Transforming Separation Science,” was released in June 2019, and was sponsored by the Department of Energy, the National Science Foundation, and the National Institute of Standards and Technology.

The report, which develops a research agenda for fundamental research in separation science, assesses research efforts to advance separation science while identifying advances in other fields that might be relevant to separation science. The report highlights advances in intersecting disciplines of materials science, systems-engineering approaches, and the use of external stimuli, instrumentation, and characterization, as well as data analytics and science that present opportunities in the field of separation science. It also identifies needs and opportunities for novel instrumentation as well as educational and human-resource needs. Potential impacts that fundamental research in separations can have in industry practices and technology are also assessed.

Two primary themes are identified in the report, which point to the need for research. The first is designing separation systems with high selectivity, capacity, and throughput, and the second is understanding temporal changes that occur within separation systems. Within those two themes, the report identifies eight research directions. Four of these fall under the first theme of designing separation systems with high selectivity, capacity, and throughput. These are:

  1. Advancing the understanding of complex systems: Designing separation systems to address multicomponent mixtures as well as species that are highly concentrated or dilute;
  2. Exploring the entire array of thermodynamic and kinetic mechanisms:Using multiple forces or cooperative binding mechanisms, for example, to improve separation selectivity and capacity;
  3. Characterizing the interface and understanding of interfacial forces: Developing methodologies that provide insight into interface structure and exploit this understanding to better enhance separation performance;
  4. Understanding physical changes that result from external forces: Elucidating the mechanism for how external stimuli (either controlled or uncontrolled) cause changes to separation media.

The other four directions fall under the theme of understanding temporal changes that occur within separation systems. These are:

5. Determining changes from nonequilibrium states that affect the chemical and physical properties of separation materials, given that separation media are often used in nonequilibrium states and may slowly undergo structural changes, which can alter its chemical and physical properties;

6. Identifying and determining the rates of fundamental chemical reactions that can change separation materials and how the reactions are influenced by operating conditions, because understanding how chemical reactions can cause the degradation of separation media and loss of performance is important to design more robust separation systems;

7. Understanding the fate of unwanted products, because understanding the mechanisms of degradation of separation media and relevant phase equilibria will aid in designing separation materials;

8. Exploring alternative strategies to address the temporal changes in separation systems, to develop practical solutions that help minimize effects that any unavoidable degradation of separation media may have on the entire separation system.

The report also examines opportunities that theory and data science can play in separations, particularly in the development of a fundamental understanding of separation materials in complex environments. Also discussed in the report are challenges that are currently faced within the field of separation science, particularly the decreasing number of separation science faculty in the United States, which threatens the leadership role of the country.

I strongly recommend that you read the report, which is free to download from the National Academies Press webpage (1). Being a part of this committee was a tremendous opportunity and it provided me with a much broader view of the field of separation science.


National Academies of Sciences, Engineering, and Medicine, A Research Agenda for Transforming Separation Science (Washington, DC: The National Academies Press,. 2019).