(377v) Propane-Selective Adsorbent g-C3N4@Zr-BPDC for Efficient Propylene Purification

Propane-Selective
Adsorbent g-C₃N₄@Zr-BPDC for Efficient Propylene Purification

Xin
Zhou^1*, Sa Wang¹

¹School of
Chemistry and Chemical Engineering, South China University of Technology,

Guangzhou, P. R. China

E-mail
address: xinzhou@scut.edu.cn

The selective
removal of propane from propylene
in C3 cracked-gas yields polymer-grade propylene within one single unit
operation,
yet the propane-selective adsorbent for propylene purification has not been reported.
We demonstrate herein the design of propane-selective adsorbents by compositing
Zr-BPDC (BPDC = biphenyl dicarboxylate) and g-C₃N₄. The
resulting composite g-C₃N₄@Zr-BPDC exhibits
well-developed porosity, with the surface are of 2123 m²·g^-1
and pore volume up to 0.84 cm³·g^-1. More
importantly, g-C₃N₄@Zr-BPDC
shows
a preferential adsorption of propane over propylene with propane capacity of 8.1
mmol·g^-1 at 100 kPa and 298 K, resulted
from the stronger interaction between propane and g-C₃N₄@Zr-BPDC
through hydrogen bonds. The mechanism of the preferential propane adsorption on
g-C₃N₄@Zr-BPDC is
discussed with the help of DFT calculations, which reveals that the effective
interaction through hydrogen bond between the hydrogen atom of propane and the
nitrogen atom of the heteroaromatic ring in g-C₃N₄@Zr-BPDC is
formed, while the adsorption between g-C₃N₄@Zr-BPDC and
propylene through hydrogen bond was weakened due to the repulsion of the lone
pair on the nitrogen atoms towards the electron-rich double bond of propylene,
resulting in the preferential adsorption of propane over propylene with high
propane capacity. In consistence with the DFT study, the isosteric heat of
propane adsorption on g-C₃N₄@Zr-BPDC is
higher than that of propylene. Hence, the propane-selective property of g-C₃N₄@Zr-BPDC
facilitating its potential application in energy-effective polymer-grade propylene
production.

Keywords:
propane-selective, adsorbent, adsorptive separation, propylene purification