Environmental Engineering Reference
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Mean diameter = 629 nm
σ =76nm
(a)
60
40
20
0
400
600 800
Fiber diameter (nm)
1000
1200
6 μm
Mean diameter = 785 nm
σ =81nm
(b)
60
40
20
0
400
600 800
Fiber diameter (nm)
1000
1200
6 μm
Mean diameter=791 nm
σ =90nm
(c)
60
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20
0
400
600 800
Fiber diameter (nm)
1000
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6 μm
figure 6.6 SEM images and diameter distribution histograms of (a) the noncrosslinked PEI/PVA nanofibers, (b) the cross-linked
PEI/PVA nanofibers, and (c) the Pd NP-containing PEI/PVA nanofibers. reprinted with permission from ref. [72]. © 2012, American
Chemical Society.
cycles of Fe(II) binding and reduction is much higher than that with a size of 2.3 nm formed via six cycles of Fe(II) binding and
reduction (Figure 6.7). This could be due to the smaller size and thus the greater specific surface area of the ZVI NPs, thereby
leading to a greater reactivity toward dye decoloration.
Similarly, ZVI NP-immobilized PAA/PVA nanofibrous mats synthesized by Xiao et al. were also able to decolorize AF with
a decoloration percentage approaching 95.8% within 40 min [14]. When compared to the synthesis of ZVI NP powder using the
method in the literature [73], the prepared ZVI NPs (1.6 nm) uniformly distributed in the polymer nanofibers have much higher
reactivity to decolorize AF. For practical environmental applications, it is essential to fabricate nanofibrous materials with
enhanced mechanical durability. In another study of ours, MWCNT-reinforced PAA/PVA nanofibrous mats containing ZVI NPs
were also used to decolorize dyes such as methyl blue, acridine orange, and AF [13]. The efficiencies of MWCNT-reinforced
PAA/PVA nanofibrous mats containing ZVI NPs to decolorize the three dyes are listed in Table 6.1. After an exposure time of
40 min, the percentage of all dyes remaining was lower than 10%.
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