Better Absorbents for Ammonia Separation

Mahdi Malmali, Giang Le, Jennifer Hendrickson, Joshua Prince, Alon V. McCormick, E. L. Cussler

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


Making ammonia from renewable wind energy at a competitive price may be possible if the conventional ammonia condenser is replaced with an ammonia absorber. Such a process change requires an ammonia selective absorbent. Supported metal halide sorbents for this separation display outstanding dynamic capacity close to their equilibrium thermodynamic limits. Alkaline earth chlorides and bromides supported on silica and zeolite Y are the most promising. MgCl2 and CaBr2 at 40% loading on silica show capacities of 60-70 mgNH3/gsorbent at 150 °C and 4 bar. Overall, cations with smaller atomic numbers show more affinity to ammonia; bromides hold ammonia more strongly than chlorides. Different solvents and metal halide mixtures do not show significant changes in the absorption capacity. These absorbents can be incorporated into ammonia reaction-absorption syntheses to achieve faster production rates.

Original languageEnglish (US)
Pages (from-to)6536-6546
Number of pages11
JournalACS Sustainable Chemistry and Engineering
Issue number5
StatePublished - May 7 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.


  • Absorption
  • Ammonia
  • Metal halides
  • Wind energy


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