posted on 2023-11-27, 17:03authored byXiaoqian Ju, Zhiyuan Yang, Jingwen Wang, Baolu Cui, Yangyang Xin, Yaping Zheng, Dechao Wang
Due
to the flexibility and versatility of the layered crystal structure
of layered double hydroxides (LDHs), they have shown great potential
in various fields. However, LDH nanosheets (LDH-NSs) are easy to agglomerate,
leading to the problem of accumulation, which hinders their further
application. Accordingly, once LDHs are combined with solvent-free
nanofluids (SFNs), the advantages of LDHs and SFNs could be combined
to achieve an extraordinary performance. However, the stacked structure
of traditional LDHs is not conducive to the exposure of hydroxyl functional
groups, and hydroxyl sites are key to the conversion of LDHs to SFNs.
Therefore, in this work, nanoflower-like LDHs (NFLs) with abundant
exposed hydroxyl groups were prepared and combined with organic oligomers
to achieve a solid-to-liquid transition. The formation mechanism of
NFLs and the grafting mechanism of OS-PEA on their surface were identified.
The prepared NFL-F3 still has good fluidity and dispersion stability
in different solvents after storage for 100 days. The high-saturated
grafting density on the surface of NFLs increased the steric hindrance
effect of the nanoparticles, thereby improving the dispersion stability
and reducing the viscosity of NFL-F3. Notably, the CO2 sorption
performance of NFL-F3 is significantly improved, which is attributed
to the voids between polymers, physical sorption, and good fluidity
caused by high-saturation grafting on the surface of NFL-F3. Finally,
by combining the sorption behavior and model fitting, it was confirmed
that the physical effect was dominant in CO2 sorption by
the NFL-F, which saved energy for the sorption–desorption process
of its industrial application. Moreover, NFL-F3 has a good CO2/N2 separation performance and cycle stability.
We envision that this general strategy will open up new insights into
the construction of innovative low-viscosity LDH-based SFNs with high
CO2 capacity and facilitate CO2/N2 selectivity and offer new directions for LDH utilizations.