By Mamadou Diallo, CalTech

1. Sustainable Supply of Critical Materials:
Addressing the Fundamental
Challenges in Separation Science and
Engineering
ACS Presidential Symposium
Tuesday August 21, 2012
Philadelphia, PA, USA

2. Mamadou Diallo
Associate Professor and Director of the
Laboratory of Advanced Materials and Systems
for Water Sustainability, Graduate School of Energy,
Environment, Water and Sustainability (EEWS), KAIST
Visiting Faculty in Environmental Science and Engineering,
Division of Engineering and Applied Science, Caltech
Chief Technology Officer and Founder of AquaNano, LLC

3. Session B Program
• Sustainable Supply of Critical Materials: The Role of Separation
Science and Engineering (Setting the Stage)
– Scientific Grand Challenges
– Education and Training
– Knowledge/Technology Transfer and Innovation
• Ensuring the Sustainable Supply of Critical Materials: Overview of
Recent Advances in Separation Science and Engineering (3
Presentations)
• Moderated Panel: Rethinking the Role of Separation Science and
Engineering—Reduce, Recycle, Repurpose!
• Concluding Remarks

4. Sustainable Supply of Critical Materials: Sources,
Extraction, Recovery and Purification
Computer Circuit Boards as Sources of Critical Materials
(Johnson et al. Environ. Sci. Technol. 2007, 41, 1759-1765)

5. Extraction and Purification of Critical Materials: The
Separations Science Toolbox
• Established Processes • Emerging/New Processes
– Solvent Extraction (SE) – SE using Ionic Liquids
– Ion Exchange – Affinity Membranes
– Sorption – Magnetic Separations
– Chromatography – Dendrimer Enhanced
– Dissolution Filtration
– Crystallization
– Electrowinning
– Pyrometallurgy

6. Extraction and Purification of Critical Materials:
Scientific Grand Challenges
• Design and synthesize high capacity, recyclable
and robust separation materials (e.g. chelating
ligands, ionic liquids, ion exchange media and
affinity membranes) that can
– Selectively extract critical materials from complex
aqueous solutions (e.g., highly acid or saline media)
– Be seamlessly integrated with existing separation
equipment including (i) packed bed reactors, (ii)
pressure vessels, (iii) clarifiers and (iii) membrane
modules and systems.

7. Sustainable Supply of Critical Materials:
Workforce Education and Training
• There has been a steady decline
in the number of students major
in mining, extractive metallurgy
and related fields dealing with
the separation science and
engineering (SSE) of critical
materials.
• Need to educate and train the
next generation of scientists and
engineers in the SSE of critical
materials.
Caltech Resnick Institute Report on Critical Materials
(Available online at http://resnick.caltech.edu/programs/critical-materials/index.html)

8. Sustainable Supply of Critical Materials:
Knowledge/Technology Transfer and Innovation
• Grand Challenge:
“ Converge Knowledge and Technology to
Build an Innovation Ecosystem for the
Sustainable Supply of Critical Materials and
Earth-Abundant Alternatives”

9. Session B Program (Continuation)
• Ensuring the Sustainable Supply of Critical Materials: Overview of Recent
Advances in Separation Science and Engineering (3 Presentations)
• Moderated Panel: Rethinking the Role of Separation Science and
Engineering—Reduce, Recycle, Repurpose!
• Concluding Remarks