Carbon dioxide adsorption over amine modified silica: Effect of amine basicity and entropy factor on isosteric heats of adsorption

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F18%3A00492305" target="_blank" >RIV/61388955:_____/18:00492305 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1016/j.cej.2018.04.187" target="_blank" >http://dx.doi.org/10.1016/j.cej.2018.04.187</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cej.2018.04.187" target="_blank" >10.1016/j.cej.2018.04.187</a>

Result language

angličtina

Original language name

Carbon dioxide adsorption over amine modified silica: Effect of amine basicity and entropy factor on isosteric heats of adsorption

Original language description

SBA-15 mesoporous silica was modified with 3-aminopropyl (AP), N-propyl ethylenediamine (DA) and N-propyl diethylenetriamine (TA) ligands. The prepared materials were characterized by thermogravimetry (TGA), small angle X-ray scattering (SAXS), nitrogen adsorption/desorption and transmission electron microscopy (HRTEM). The carbon dioxide adsorption/desorption experiments were performed at 273 K, 293 K, 313 K and 333 K. The adsorption capacity of CO2 at pressures below 2 kPa well correlates with number of amine centers in the respective ligand. Based on the adsorption isotherms, measured at different temperatures, the isosteric heats of adsorption (Q(st)) were calculated. The Q(st) values correlate with the basicity of the nitrogen atoms of respective amine ligands and their steric availability. The AP and DA ligands with the higher basicity of amine nitrogen showed the higher isosteric heats of adsorption at zero coverage (Q(st) = 72 kJ/mol), while TA ligand, with the lower basicity and steric availability of nitrogen atoms exhibited at zero coverage the lowest value of isosteric heat of adsorption (Q(st) = 40 kJ/mol). This low value shows, that in addition to amine basicity, also the entropic factor may influence the differences in isosteric heats of adsorption. While the mono-and diamine ligands loaded in the pores of SBA-15 are flexible enough to react with the carbon dioxide, the lower isosteric heats of adsorption of carbon dioxide over the TA ligands may be due to unfavorable entropic factor associated with filling of the pores of SBA-15 by bulkier TA ligands. Steric hindrance among TA ligands may result in lower flexibility of TA ligands and unfavor the formation of carbamates through intramolecular reaction in the pores of SBA-15.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10403 - Physical chemistry

Project

<a href="/en/project/GBP106%2F12%2FG015" target="_blank" >GBP106/12/G015: Intelligent design of nanoporous adsorbents and catalysts</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemical Engineering Journal

ISSN

1385-8947

e-ISSN

—

Volume of the periodical

348

Issue of the periodical within the volume

SEP 2018

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

11

Pages from-to

327-337

UT code for WoS article

000434467000033

EID of the result in the Scopus database

2-s2.0-85046694903