UV-visible spectrometry to determine the amount of each dye before and after
filtration. Over 95 and 90% removal of 7 and 1 was achieved at 1 to 1.5 bar
transmembrane pressure with solution concentrations of over 54 and 35 mg/L,
respectively. However, in case of negatively charged 8, removal was not successful.
By heating membranes at 300
C for 1.0 h, adsorbed dyes were eliminated
(Foorginezhad and Zerafat 2017). The sequencing batch reactor in a combination
of nanofiltration membranes was designed to reuse the industrial waste effluent by
removing remazol (yellow, blue, red) RR dyes. Over 90% of decolorization efficiency was achieved for blue and red dye and above 75% for yellow.
However, when a combined feed of aforementioned dyes was used, the rejection
percentage was higher than 40%, indicating relatively low and inferior color removal
efficiencies for all three dyes (Zuriaga-Agusti et al. 2010). The integration of
biological methods with nanofiltration for the better removal and decolorization of
the wastewater was successfully studied. In a study, Reactive Red 120 was studied
with such an integrated method, and nanofiltration concentrate was significantly
decolorized by biological process and endorsed the potential usage of the designed
method for textile wastewater (Paździor et al. 2009).
The spiral wound nanofiltration module opted for the elimination/separation of
dyes from the textile waste effluents. The effects of feed pressure, dye concentration,
and feed flow rate on dye rejection and recovery were studied. The maximum
rejection was observed for 20. The highest reflection coefficient (σ ¼ 0.969) was
observed for 20, which marks the impermeability of the nanofiltration membrane to
the solute. Permeate characteristics were optimized using Spiegler-Kedem-based
model and were not in good correlation with experimental data. Thus, for scalable
usage in the future, a more accurate module based on Spiegler-Kedem theory could
opt for the textile industry (Dash and Kumar 2017). By bringing nanofiltration in
combination with reverse osmosis, composite polyamide membrane modules were
reported to be highly effective for decolorization of the wastewater containing dyes
and salts. Flux rate was comparable to that of pure water. The effect of varied
concentration of dyes and salts was also optimized on spiral wound membrane, and
results strongly endorsed the potential scalable usage of the designed membranes
(Nataraj et al. 2009).
Polyamide thin-film composite was modified by diethanolamine and used to
remove 1, Sunset Yellow, 6, and natural red. Modified membranes have shown
promising results with steady-state water fluxes of an aqueous solution containing
dyes mentioned above, which were quite high in a range between 37 and 54%.
Meanwhile, flux decline ratio due to membrane fouling was quite low in a range
between 37 and 49%. Through nanofiltration, modified composite membranes have
demonstrated efficient dye removal from aqueous solutions (Liu et al. 2017). In
another study, nanofiltration of textile waste materials with different commercially
available membranes such as Desal 5 DK, Desal 5 DL, N30F, and NF PES10 was
reported. The impact of temperature change on permeates quality, and membrane
fouling was studied from 20 to 70
C. Up to 80% of color rejection was noted with
nanofiltration membranes, and permeate quality was quite satisfactory for recycling
the effluents (Xuan Nguyen and Van der Bruggen 2015).
616
R. S. Ashraf et al.
filtration. Over 95 and 90% removal of 7 and 1 was achieved at 1 to 1.5 bar
transmembrane pressure with solution concentrations of over 54 and 35 mg/L,
respectively. However, in case of negatively charged 8, removal was not successful.
By heating membranes at 300
C for 1.0 h, adsorbed dyes were eliminated
(Foorginezhad and Zerafat 2017). The sequencing batch reactor in a combination
of nanofiltration membranes was designed to reuse the industrial waste effluent by
removing remazol (yellow, blue, red) RR dyes. Over 90% of decolorization efficiency was achieved for blue and red dye and above 75% for yellow.
However, when a combined feed of aforementioned dyes was used, the rejection
percentage was higher than 40%, indicating relatively low and inferior color removal
efficiencies for all three dyes (Zuriaga-Agusti et al. 2010). The integration of
biological methods with nanofiltration for the better removal and decolorization of
the wastewater was successfully studied. In a study, Reactive Red 120 was studied
with such an integrated method, and nanofiltration concentrate was significantly
decolorized by biological process and endorsed the potential usage of the designed
method for textile wastewater (Paździor et al. 2009).
The spiral wound nanofiltration module opted for the elimination/separation of
dyes from the textile waste effluents. The effects of feed pressure, dye concentration,
and feed flow rate on dye rejection and recovery were studied. The maximum
rejection was observed for 20. The highest reflection coefficient (σ ¼ 0.969) was
observed for 20, which marks the impermeability of the nanofiltration membrane to
the solute. Permeate characteristics were optimized using Spiegler-Kedem-based
model and were not in good correlation with experimental data. Thus, for scalable
usage in the future, a more accurate module based on Spiegler-Kedem theory could
opt for the textile industry (Dash and Kumar 2017). By bringing nanofiltration in
combination with reverse osmosis, composite polyamide membrane modules were
reported to be highly effective for decolorization of the wastewater containing dyes
and salts. Flux rate was comparable to that of pure water. The effect of varied
concentration of dyes and salts was also optimized on spiral wound membrane, and
results strongly endorsed the potential scalable usage of the designed membranes
(Nataraj et al. 2009).
Polyamide thin-film composite was modified by diethanolamine and used to
remove 1, Sunset Yellow, 6, and natural red. Modified membranes have shown
promising results with steady-state water fluxes of an aqueous solution containing
dyes mentioned above, which were quite high in a range between 37 and 54%.
Meanwhile, flux decline ratio due to membrane fouling was quite low in a range
between 37 and 49%. Through nanofiltration, modified composite membranes have
demonstrated efficient dye removal from aqueous solutions (Liu et al. 2017). In
another study, nanofiltration of textile waste materials with different commercially
available membranes such as Desal 5 DK, Desal 5 DL, N30F, and NF PES10 was
reported. The impact of temperature change on permeates quality, and membrane
fouling was studied from 20 to 70
C. Up to 80% of color rejection was noted with
nanofiltration membranes, and permeate quality was quite satisfactory for recycling
the effluents (Xuan Nguyen and Van der Bruggen 2015).
616
R. S. Ashraf et al.