It was also interesting to find out if theĬations, which are present in zeolites discussed in the work of Matito-Martos High separation performance, which was found in the paper by Kowalczyk, 18 by CNTs for the H 2/CO 2 separation prompted us to ask whether such a performance can alsoīe reached using a CNT for the ternary system NO x/N 2. However, the question remained open whether other materialsĬan show even higher, may be even much higher, performance. Hence, strong van der Waals forces couldīe expected. Material are only slightly larger than the size of the N 2O 4 molecule. The strong separation effect because the pores and channels of this Metal–organic framework MIL-127 has been chosen to investigate Part of air, but tests and earlier work show also that the adsorptionīehavior of O 2 on several porous materials was found to Was represented by N 2 in the work of Fritzsche et al. Lower concentrationsīe too small for a reasonable statistics in the simulations. N atoms in NO x (N 2O 4 + NO 2) to N atoms in N 2 in the gas phase.įor a higher temperature, the selectivity was smaller. Up to almost 1000 at 298 K and 2 bar for a concentration of NO x that was characterized by the ratio 1:40 of (box A) or in the adsorbed phase (box B) of the Gibbs ensemble, respectively Īnd and are the number of N atoms in N 2 in box A and box b, respectively.īy formula 2, for MIL-127, was found to be Selectivity due to both adsorption and reaction and are the sum of the numbers of all N atoms Selectivity S ar was defined in ref ( 5) by the following equation: Moreover, theĬommon formula for the selectivity of a binary mixture 16 can thus be used for the ternary mixture as N atoms in NO x (N 2O 4 + NO 2) is not affected by the chemical reaction ( reaction 1). We will alsoĭo that in the present paper for two reasons. Has been used in ref ( 5) to treat the ternary mixture like a binary mixture. (N 2O 4 + NO 2) to N atoms in N 2 in the gas phase, or in the adsorbed phase, respectively, To characterize the selectivity between the total amount To investigate the adsorption and reaction of a ternary mixture, N 2O 4/NO 2/N 2, on the MOF material 5 used the Gibbs ensemble Monte Carlo (GEMC) and RxMC simulations Question of use of this type of adsorption and reaction for the separationįrom N 2, respectively) under the consideration of the chemical The presence of other gases have been considered. However, in ref ( 15), only the NO x without Monte Carlo (GCMC) computer simulations and the reactive Monte Carlo Taking into account the chemical reaction ( reaction 1) was examined in the pioneering paper of The adsorption of NO x by zeolite materials Taking reaction 1 into account should improve Reaction is described and discussed in more detail in the Supportingįor separation purposes has been examined in several papers, 6− 14 which are discussed in more detail in ref ( 5). where the separation of NO 2 from airĪt 374 K using several Zeolitic Imidazolate Framework (ZIF) materialsĬonsider only NO 2 because at 374 K, the NO x exist almost entirely as NO 2. An example is the paper ofĬhokbunpiam et al. Very high and at very low temperatures where only NO 2 or Hence, investigation of the separation of NO x from air must take into account this reaction except at At room temperatureĪnd at lower temperatures, most of the NO x molecules are N 2O 4, while at higher temperatures, 3 investigated this reaction in experiments. Of this reaction strongly depends upon the N 2O 4 are in a permanent chemical reaction with In air, NO x are present mainly as NO 2 and N 2O 4. NO x in porous materials can be very helpful. To make such decisions,ĭetailed knowledge about the basic mechanisms of the adsorption of Investigate how the use of such materials can save energy and expensiveĮquipment in comparison to other methods. Use porous materials like activated carbon, zeolites, and metal–organicįrameworks (MOFs) for the separation of NO x from other gases by selective adsorption. NO x are selective catalytic reduction 2 or the storage as nitrates. In designing systems to eliminate NO x emissionsįrom fossil fuel combustion or from air. Protect the environment, significant efforts have been made Main sources are human activities like combustion engines. Matter (PM2.5), also gases like sulfur dioxide (SO 2) andīe produced by lightning, volcanos, and other natural sources, but Due to its severe threat to human health,Ī serious environmental problem especially in developing countriesĪnd also in highly industrialized countries.