TY - JOUR
T1 - Postsynthetic Modification of Zeolite Internal Surface for Sustainable Capture of Volatile Organic Compounds under Humid Conditions
AU - Lee, Kang Min
AU - Kim, Nam Sun
AU - Numan, Muhammad
AU - Kim, Jeong Chul
AU - Cho, Hae Sung
AU - Cho, Kanghee
AU - Jo, Changbum
N1 - Publisher Copyright:
©
PY - 2021/11/17
Y1 - 2021/11/17
N2 - Although low-cost, high-surface-area crystalline aluminosilicate zeolites have been recognized as promising adsorbents for the capture of volatile organic compounds (VOCs), their hydrophilic nature leads to a significant loss of performance owing to the ubiquitous presence of water vapor in the VOC stream. Herein, the aluminosilicate zeolites (i.e., mordenite and nanocrystalline β) are functionalized via a solvothermal post-treatment with methyl iodide as the grafting agent. The methyl groups are primarily attached to the zeolite internal surface via covalent bonding between internal bridging O and -CH3, as evidenced by multiple analysis data. The static isotherms and diffusional studies clearly reveal a remarkable decrease in both the rate of water adsorption and the water affinity due to the attachment of methyl groups to the micropore walls, thus enhancing the water tolerance compared to that of pristine zeolites. In addition, CH3I-functionalized zeolites are investigated as adsorbents for the removal of benzene under dry and humid conditions, and their performance is compared to that of CH3Si(-OCH3)3-functionalized zeolites, wherein the methyl groups have been grafted onto the external surface. The results demonstrate that, although the benzene adsorption capacity under dry conditions is decreased upon internal surface functionalization, the loss of VOC adsorption capacity in the presence of H2O vapor is effectively prevented. By contrast, external surface functionalization is ineffective for preventing the negative effects of moisture upon the benzene adsorption capacity. As a result, CH3I-functionalized zeolites exhibit superior dynamic adsorption performance for benzene at 318 K under humid conditions (relative humidity: 80%), with a saturated adsorption capacity of 64.9 mg g-1. This work provides an easy strategy for tailoring the adsorption properties of aluminosilicate zeolites for adsorption/separation and other advanced applications.
AB - Although low-cost, high-surface-area crystalline aluminosilicate zeolites have been recognized as promising adsorbents for the capture of volatile organic compounds (VOCs), their hydrophilic nature leads to a significant loss of performance owing to the ubiquitous presence of water vapor in the VOC stream. Herein, the aluminosilicate zeolites (i.e., mordenite and nanocrystalline β) are functionalized via a solvothermal post-treatment with methyl iodide as the grafting agent. The methyl groups are primarily attached to the zeolite internal surface via covalent bonding between internal bridging O and -CH3, as evidenced by multiple analysis data. The static isotherms and diffusional studies clearly reveal a remarkable decrease in both the rate of water adsorption and the water affinity due to the attachment of methyl groups to the micropore walls, thus enhancing the water tolerance compared to that of pristine zeolites. In addition, CH3I-functionalized zeolites are investigated as adsorbents for the removal of benzene under dry and humid conditions, and their performance is compared to that of CH3Si(-OCH3)3-functionalized zeolites, wherein the methyl groups have been grafted onto the external surface. The results demonstrate that, although the benzene adsorption capacity under dry conditions is decreased upon internal surface functionalization, the loss of VOC adsorption capacity in the presence of H2O vapor is effectively prevented. By contrast, external surface functionalization is ineffective for preventing the negative effects of moisture upon the benzene adsorption capacity. As a result, CH3I-functionalized zeolites exhibit superior dynamic adsorption performance for benzene at 318 K under humid conditions (relative humidity: 80%), with a saturated adsorption capacity of 64.9 mg g-1. This work provides an easy strategy for tailoring the adsorption properties of aluminosilicate zeolites for adsorption/separation and other advanced applications.
KW - adsorption
KW - functionalization
KW - humidity
KW - volatile organic compounds
KW - zeolites
UR - http://www.scopus.com/inward/record.url?scp=85119430224&partnerID=8YFLogxK
U2 - 10.1021/acsami.1c16108
DO - 10.1021/acsami.1c16108
M3 - Article
C2 - 34726376
AN - SCOPUS:85119430224
SN - 1944-8244
VL - 13
SP - 53925
EP - 53934
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
IS - 45
ER -