Modeling\nWater and Ammonia Adsorption in Hydrophobic\nMetal–Organic Frameworks: Single Components and Mixtures

Abstract

Capturing\nammonia under humid conditions is difficult because chemical\nfunctionalities that attract ammonia tend to also attract water. In\nthis work, three hydrophobic metal–organic frameworks (MOFs)\nwere assessed for ammonia capture under dry and humid conditions.\nUsing grand canonical Monte Carlo simulations, pure water isotherms\nwere calculated and showed good agreement with experiment. The low\nheats of adsorption for water substantiate the hydrophobic nature\nof these MOFs. Simulated ammonia isotherms predict that hydrophobic\nMOFs adsorb similar amounts of ammonia under dry and humid conditions.\nThese results suggest that hydrophobic MOFs could be appropriate candidates\nfor ammonia capture under humid conditions. The simulations also provide\ndetailed information on the behavior of water and mixtures of water\nand ammonia confined in hydrophobic pores.