TY - JOUR
T1 - Vapor-phase adsorption of alkylaromatics on aluminum-trimesate MIL-96
T2 - An unusual increase of adsorption capacity with temperature
AU - Lee, Ji Sun
AU - Jhung, Sung Hwa
PY - 2010/4/1
Y1 - 2010/4/1
N2 - Porous aluminum-trimesate (MIL-96), one of the metal-organic frameworks (MOFs), has been synthesized hydrothermally under autogeneous pressure in water as the solvent. The MIL-96 adsorbs nitrogen readily at liquid nitrogen temperature to show permanent porosity (SBET = 532 m2/g, SLangmuir = 700 m2/g). Moreover, the desorption of adsorbed nitrogen does not to show any hysteresis between the adsorption and desorption isotherms. A vapor-phase adsorption study (temperature: 30-110 °C) shows that MIL-96 can uptake aromatic compounds such as p-xylene, m-xylene and 1,3,5-TMB (trimethylbenzene). However, a larger molecule such as 1,3,5-TiPB (triisopropylbenzene) is only negligibly adsorbed on MIL-96. The adsorption rate of 1,3,5-TMB (even at a high temperature of 70 °C) is very slow compared with that of p-xylene (at 30 °C). Very interestingly, the adsorption capacity of 1,3,5-TMB increases with increasing adsorption temperature (up to 90 °C), which is very rare because an adsorption is usually an exothermic process. All of these results may be explained by the fact that the MIL-96 has a pore size similar to a kinetic diameter of 1,3,5-TMB. Moreover, the results may suggest that the framework of MIL-96 is flexible and the lattice vibrates more widely at high temperature to increase the effective pore size. The flexible structure of MIL-96 demonstrated in this study may enlarge the applications of MOFs for the storage of chemicals and controlled release such as drug delivery.
AB - Porous aluminum-trimesate (MIL-96), one of the metal-organic frameworks (MOFs), has been synthesized hydrothermally under autogeneous pressure in water as the solvent. The MIL-96 adsorbs nitrogen readily at liquid nitrogen temperature to show permanent porosity (SBET = 532 m2/g, SLangmuir = 700 m2/g). Moreover, the desorption of adsorbed nitrogen does not to show any hysteresis between the adsorption and desorption isotherms. A vapor-phase adsorption study (temperature: 30-110 °C) shows that MIL-96 can uptake aromatic compounds such as p-xylene, m-xylene and 1,3,5-TMB (trimethylbenzene). However, a larger molecule such as 1,3,5-TiPB (triisopropylbenzene) is only negligibly adsorbed on MIL-96. The adsorption rate of 1,3,5-TMB (even at a high temperature of 70 °C) is very slow compared with that of p-xylene (at 30 °C). Very interestingly, the adsorption capacity of 1,3,5-TMB increases with increasing adsorption temperature (up to 90 °C), which is very rare because an adsorption is usually an exothermic process. All of these results may be explained by the fact that the MIL-96 has a pore size similar to a kinetic diameter of 1,3,5-TMB. Moreover, the results may suggest that the framework of MIL-96 is flexible and the lattice vibrates more widely at high temperature to increase the effective pore size. The flexible structure of MIL-96 demonstrated in this study may enlarge the applications of MOFs for the storage of chemicals and controlled release such as drug delivery.
KW - Adsorption
KW - Aluminum-trimesate
KW - Flexible pore
KW - Metal-organic frameworks
KW - Microporous materials
UR - http://www.scopus.com/inward/record.url?scp=71549171913&partnerID=8YFLogxK
U2 - 10.1016/j.micromeso.2009.09.021
DO - 10.1016/j.micromeso.2009.09.021
M3 - Article
AN - SCOPUS:71549171913
SN - 1387-1811
VL - 129
SP - 274
EP - 277
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
IS - 1-2
ER -