Environmental Engineering Reference
In-Depth Information
Crosslinking by
GA vapor
PEI/PVA nanofibers
Crosslinked PEI/PVA nanofibers
PdCl
2
-
K
2
PdCl
4
+
N
H
n
PdCl
2
-
-complexed PEI/PVA nanofibers
NaBH
4
Pd NP
Pd NP-immobilized PEI/PVA nanofibers
figure 6.5
Schematic illustration of the immobilization of Pd NPs within electrospun PEI/PVA nanofibers. reprinted with permission
from ref. [72]. © 2012, American Chemical Society.
on the basis of work related to the immobilization of Au NPs, Huang et al. [72] used the same electrospun PEI/PVA
nanofibrous mats as nanoreactors to immobilize Pd NPs. The complete fabrication process is shown in Figure 6.5. In
brief, cross-linked PEI/PVA nanofibrous mats were soaked in a K
2
PdCl
4
aqueous solution to allow PdCl
4
2−
ions to complex
with available PEI amine groups through ionic exchange. Then, NabH
4
solution was added to reduce PdCl
4
2−
to form Pd
NPs. Similar to the immobilization of ZVI or Au NPs within nanofibers [13, 14, 69, 70], the immobilization of Pd NPs
does not appreciably change the morphology of PEI/PVA nanofibers (Figure 6.6). EdS analysis confirmed the existence
of Pd element within the nanofibers. TEM images show that these Pd NPs with a mean diameter of 2.6 nm are quite
uniformly distributed within the fibers with a small portion of particles having a denser distribution at the outer surface
of the fibers. Furthermore, thermogravimetric analysis shows that the loading capacity of Pd NPs within the nanofibrous
mat is about 13.1%. And this considerable amount of Pd NPs loaded endows the nanofibrous material with the potential
to tackle tough environmental problems.
6.5 eNviroNMeNtal applicatioNs of Hybrid Metal Np-coNtaiNiNg
polyMer NaNofibers
6.5.1
decoloration
The major advantage of NP-immobilized polymer nanofibers is that the fibrous mats can be easily separated from the contami-
nated water, which is an ideal property enabling their use as reusable and recyclable filtration or sorption materials, and simulta-
neously to avoid possible secondary contamination. The prepared ZVI NPs immobilized onto the (PAA/PdAdMAC)
6
-coated
CAc nanofibrous mats have been used to decolorize dye-contaminated water [20]. In that study, Xiao et al. used ZVI
NP-immobilized (PAA/PdAdMAC)
6
-coated CAc nanofibrous mats for the decoloration of acid fuchsin (AF), a common organic
dye in textile industry. The results show that the decoloration efficiency of the ZVI NPs with a size of 1.4 nm formed via two