Computational Screening of Porous Metal-Organic Frameworks and Zeolites for the Removal of SO 2 and NO x from Flue Gases Weizhen Sun State-Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China Dept. of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 Key Laboratory of Advanced Control and Optimization for Chemical Processes, East China University of Science and Technology, Shanghai 200237, China Li-Chiang Lin Dept. of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 Xuan Peng Dept. of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 Dept. of Automation, College of Information Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China Berend Smit Dept. of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 Dept. of Chemistry, University of California, Berkeley, CA 94720 Materials Sciences Div., Lawrence Berkeley National Laboratory, Berkeley, CA 94720 DOI 10.1002/aic.14467 Published online April 23, 2014 in Wiley Online Library (wileyonlinelibrary.com) Sulfur oxides (SO 2 ) and nitrogen oxides (NO x ) are principal pollutants in the atmosphere due to their harmful impact on human health and environment. We use molecular simulations to study different adsorbents to remove SO 2 and NO x from flue gases. Twelve representative porous materials were selected as possible candidates, including metal-organic frameworks, zeolitic imidazolate frameworks, and all-silica zeolites. Grand canonical Monte Carlo simulations were per- formed to predict the (mixture) adsorption isotherms to evaluate these selected materials. Both Cu-BTC and MIL-47 were identified to perform best for the removal of SO 2 from the flue gases mixture. For the removal of NO x , Cu-BTC was shown to be the best adsorbent. Additionally, concerning the simultaneous removal of SO 2 , NO x , and CO 2 , Mg- MOF-74 gave the best performance. The results and insights obtained may be helpful to the adsorbents selection in the separation of SO 2 and NO x and carbon capture. V C 2014 American Institute of Chemical Engineers AIChE J, 60: 2314– 2323, 2014 Keywords: adsorbent material, harmful gas removal, adsorption separation, molecular simulation Introduction Under the Clean Air Act, the U.S. Environmental Protec- tion Agency is required to set National Ambient Air Quality Standards (NAAQS) for pollutants harmful to public health and the environment. 1 Based on this NAAQS, six principal air pollutants were identified, including particulate matter, ground level ozone, carbon monoxide, sulfur oxides (SO 2 ), nitrogen oxides (NO x ), and lead. Among them, a portion of particulate matter is formed in the air when gases such as SO 2 and NO x are transformed by chemical reactions. The ground level ozone is created by chemical reactions between NO x and volatile organic compounds in the presence of sun- light. It is clear that besides their direct significant impacts on human health and environment, both SO 2 and NO x also exert more negative effects by forming other air pollutants. These two most harmful air pollutants are emitted into the atmosphere mainly through automobile exhaust gases and industrial flue gases. 2 For example, in China 87% of SO 2 and 67% of NO x come from coal-fired combustion. 3 A typi- cal composition of untreated flue gases from coal-fired plants burning low-sulfur coal is as follows (by volume): N 2 (70– 75%), CO 2 (15–16%), O 2 (3–4%), water vapor (5–7%), SO 2 Additional Supporting Information may be found in the online version of this article. Correspondence concerning this article should be addressed to B. Smit at berend-smit@berkeley.edu. V C 2014 American Institute of Chemical Engineers 2314 AIChE Journal June 2014 Vol. 60, No. 6