Details

Autor(en) / Beteiligte

• Moreira, Mariana A.
• Santos, Mónica P. S.
• Silva, Cláudia G.
• Loureiro, José M.
• Chang, Jong-San
• Serre, Christian
• Ferreira, Alexandre F. P.
• Rodrigues, Alírio E.

Titel

Adsorption equilibrium of xylene isomers and ethylbenzene on MIL-125(Ti)_NH2: the temperature influence on the para-selectivity

Ist Teil von

• Adsorption : journal of the International Adsorption Society, 2018-11, Vol.24 (8), p.715-724

Ort / Verlag

New York: Springer US

Erscheinungsjahr

2018

Quelle

Springer

Beschreibungen/Notizen

• The separation of xylene isomers feedstock containing ethylbenzene is still a relevant industrial challenge. The increase in p- xylene consumption worldwide promotes the search for more efficient separation processes. One possible way to achieve such a goal is to upgrade the existing SMB units with selective adsorbents operating at lower temperatures. Therefore, new adsorbents such as the functionalized metal–organic framework MIL-125(Ti)_NH 2 appear as strong candidates. The MIL-125(Ti)_NH 2 was tested in this work for the selective adsorption and separation of xylene isomers, including ethylbenzene, in liquid phase and using n- heptane as eluent. In this way, a detailed experimental study of binary and multicomponent adsorption equilibrium of xylene isomers in MIL-125(Ti)_NH 2 , at three temperatures (299 K, 313 K and 343 K) in liquid phase, was performed and is reported in this manuscript. Ternary breakthrough experiments indicate competitive adsorption between p- xylene over the two other isomers. Indeed the selectivity values range from 1.4 to 1.9 and 1.5 to 2.3 for the p- xylene/ m -xylene and p -xylene/ o -xylene pairs, respectively, increasing with the temperature. Similar trends are observed for the quaternary mixtures, where p- xylene and ethylbenzene are adsorbed preferentially. However, the MIL-125(Ti)_NH 2 does not discriminate between the two more linear molecules at lower temperatures. Yet, when temperature is increased to 343 K, the adsorption of p- xylene becomes more favorable than ethylbenzene, presenting a selectivity of 1.3. Therefore, within the studied temperature range a temperature, 343 K is the most favorable temperature to operate the SMB process, for the p- xylene production from mixtures containing ethylbenzene.