three stages (Zhang and Ding 2015): for the initial stage
(VRR < 2), the leaf proteins accumulated on membrane,
because of the enhancement of concentration polarization,
and thus, protein foulants deposited and adsorbed on membrane rapidly; at the second stage (2 < VRR < 5), due to
high shear stress effect, flux decline was not significant; in
the last stage (5 < VRR), flux stabilized, and there was an
equilibrium between TMP and shear rate (Luo et al. 2012).
Although flux was reduced with VRR clearly, the final flux
was still higher than 25 L m
−2 h
−1 , indicating that SEF was
able to efficiently separate and concentrate proteins. For the
separation performance, the crude protein concentration and
Brix of permeate solution elevated by degrees with VRR.
When VRR rose, concentration polarization strengthened,
then higher concentration gradient for leaf proteins and other
matters formed (Luo et al. 2010), enhancing transmissions of
crude proteins and soluble matters. On the other hand, the
“dilution” effect decreased caused by lower flux at higher
VRR, which also reduced solute concentration in permeate.
Furthermore, the operational conditions exacted an important impact on flux behavior. The US100P membrane with
large pore size showed a greater permeate flux, but a higher
crude protein concentration and Brix in permeate. Greater
shear stress generated by higher rotating speed diminished
concentration polarization, and subsequent membrane fouling, while reinforcing flux. At the same time, the great shear
stress also reduced the concentration gradient of proteins and
soluble matters; thus, the concentrations of crude protein and
Brix in permeate decreased. Besides, membrane pores
expended at high temperature (Jawor and Hoek 2009), while
molecule’s motion straightened (Zhang et al. 2013), so flux
improved. Meanwhile, an expending membrane pore size
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 14 Permeate flux as a
function of TMP at various
rotating speeds and VRRs for MF
(a, c and e) and UF (b, d and f)
Shear-Enhanced Filtration (SEF) for the Separation …
139
(VRR < 2), the leaf proteins accumulated on membrane,
because of the enhancement of concentration polarization,
and thus, protein foulants deposited and adsorbed on membrane rapidly; at the second stage (2 < VRR < 5), due to
high shear stress effect, flux decline was not significant; in
the last stage (5 < VRR), flux stabilized, and there was an
equilibrium between TMP and shear rate (Luo et al. 2012).
Although flux was reduced with VRR clearly, the final flux
was still higher than 25 L m
−2 h
−1 , indicating that SEF was
able to efficiently separate and concentrate proteins. For the
separation performance, the crude protein concentration and
Brix of permeate solution elevated by degrees with VRR.
When VRR rose, concentration polarization strengthened,
then higher concentration gradient for leaf proteins and other
matters formed (Luo et al. 2010), enhancing transmissions of
crude proteins and soluble matters. On the other hand, the
“dilution” effect decreased caused by lower flux at higher
VRR, which also reduced solute concentration in permeate.
Furthermore, the operational conditions exacted an important impact on flux behavior. The US100P membrane with
large pore size showed a greater permeate flux, but a higher
crude protein concentration and Brix in permeate. Greater
shear stress generated by higher rotating speed diminished
concentration polarization, and subsequent membrane fouling, while reinforcing flux. At the same time, the great shear
stress also reduced the concentration gradient of proteins and
soluble matters; thus, the concentrations of crude protein and
Brix in permeate decreased. Besides, membrane pores
expended at high temperature (Jawor and Hoek 2009), while
molecule’s motion straightened (Zhang et al. 2013), so flux
improved. Meanwhile, an expending membrane pore size
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 14 Permeate flux as a
function of TMP at various
rotating speeds and VRRs for MF
(a, c and e) and UF (b, d and f)
Shear-Enhanced Filtration (SEF) for the Separation …
139