Adsorption of hydrogen sulphide on Metal-Organic Frameworks

Abstract

Three new sets of interatomic potentials to model hydrogen sulphide (H 2 S) have been fitted. One of them is a 3-sites potential (which we named 3S) and the other two are 5-sites potentials (which we named 5S and 5Sd). The molecular dipole of the 3S and 5S potentials is 1.43 D, which is the value usually employed for H 2 S potentials, while the dipole of the 5Sd is the dipole measured experimentally for the H 2 S molecule, circa 0.974 D. The interatomic potentials parameters were obtained by fitting the experimental vapourliquid equilibrium, vapour pressure and liquid density curves. The potential parameters fitted so far for H 2 S have been obtained applying long-range corrections to the Lennard-Jones energy. For that reason, when a cut and shift of the Lennard-Jones potentials is applied they do not yield the correct results. We employed a cut and shift of the Lennard-Jones potentials in the fitting procedure, which facilitates the use of the new potentials to model H 2 S adsorption on systems such as Metal-Organics Frameworks (MOFs). We have employed the newly developed potentials to study the adsorption of H 2 S on Cu-BTC, MIL-47 and IRMOF-1 and the results agree with the available electronic structures calculations. All calculations (both quantum and interatomic potential-based) predict that H 2 S does not bind to the Cu atoms in Cu-BTC.

H2S interaction with HKUST-1 and ZIF-8 MOFs: A multitechnique study

“…Some experimental evidence of H 2 S interaction with HKUST-1 is reported by Petit et al, where they have proposed a mechanism of degradation of HKUST-1 upon H 2 S adsorption [18e20]. On the other hand, GutierrezeSevillano et al [21] have studied H 2 S adsorption on three well known MOFs, namely HKUST-1, MIL-47(V), and IRMOF-1(Zn). According to their study, the H 2 S adsorption energy in the case of HKUST-1, is À43.4 (kJ mol À1 ) which is lower than H 2 O adsorption energy of À46.7 (kJ mol À1 ) and they claim that there must be something missing in the mechanisms proposed so far to explain the degradation observed in the MOF upon adsorption of H 2 S. Theoretical studies on CPO-27-Ni have also shown higher interaction energy for H 2 O than H 2 S [10].…”

RASPA: molecular simulation software for adsorption and diffusion in flexible nanoporous materials

“…These types of simulations are also useful for re-optimising force fields for a different cut-off or change from tail-correction to a shifted potential type. [18,19] The chief advantage of VLE-fitted force fields is that over a large range of pressures and temperatures, the density of the fluid is accurately reproduced.…”

A new force field for H2S and its binary and ternary mixtures with CO2 and CH4

“…(1) for the repulsion-dispersion interactions. In line with the force fields developed previously for this molecule [47][48][49][50][51][52][53][54][55][56], we add to the repulsion-dispersion interaction terms a distribution of point charges to model the polar nature of hydrogen sulfide. Building on the ability of the force field proposed by Kristof and Liszi to model mixtures of H 2 S with short alkanes [57][58][59][60], we retain the same distribution of 4 point charges [47] to model the polar nature of H 2 S, with 1 charge q S = 0.4e on the S atom, 1 charge q H = 0.25e on each H atom and 1 charge q a = −0.9e on the bisector of the H-S-H angle, at a distance ı = 0.1933Å from the S atom.…”