application of this topic to the different industries. These four
points embrace the four main industries in which forward
osmosis applications have a major impact—chemical
industry, desalination of drinking water, food industry and
pharmaceutical industry.
4.1 Forward Osmosis in Chemical Industry
Forward osmosis in chemical industry refers usually to the
wastewater treatment originated from different industries.
Many references have reported the implementation of FO
with different effluents, and some of them are explained in
this section (Soler-Cabezas et al. 2018; Law and Mohammad
2018; Cho et al. 2012; Kalafatakis et al. 2017; Shibuya et al.
2017).
Soler-Cabezas et al. (2018) corroborated the recovery of
nitrogen and phosphorus coming from the anaerobically
digested sludge concentrate through FO membranes. They
tested two draw solutions: a residual effluent from ammonia
elimination stage and brine from seawater. Moreover, they
tested two different FO membranes: CTA and Aquaporinbased membranes. They obtained a high nitrogen concentration with both membranes and draw solutions. They
concluded that the employment of ammonia absorption
effluent enhanced the nitrogen concentration.
Law and Mohammad (2018) investigated the role of the
FS pH of succinic acid concentration by FO as shown in
Fig. 5. They employed CTA membranes and examined both
the water flux and the reverse solute flux, using seawater as
draw solution. The results revealed that the pH affects the
FO performances. A strong effect was pointed out on the
succinate rejection for which nearly 100% rejections were
achieved at pH above its pKa = 2 value. With real seawater
as the draw solution, moderate water fluxes (<4 L m
−2 h
−1 )
were observed. They concluded that is possible to obtain
considerable water fluxes by swinging pH value.
Cho et al. (2012) focused on organic acid separation and
dewatering processes using nanofiltration and FO processes.
The organic acids are obtained during biomass decomposition under an anaerobic fermentation process, and their
accumulation hinders the microbial metabolism in the fermentation broths. Therefore, the authors of this investigation
proposed a novel research to remove organic acids through a
combination of nanofiltration and forward osmosis membranes. Using nanofiltration membranes, aqueous organic
acids can be selectively separated from pretreated fermentation feed solutions while other organics and many salts can
be rejected using these processes by varying pH conditions
in the feed. Finally, a low-energy-consuming forward
osmosis process was applied for dewatering in the aqueous
organic acid solutions to concentrate organic acid.
Kalafatakis et al. (2017) proposed crude glycerol and
enzymatically pretreated wheat straw as draw solution in
FO application against RO. This DS is generated as
second-generation product of bio-refineries. They applied
Aquaporin Inside™ TFC membranes, crude glycerol and
wheat straw hydrolysate and demonstrated water fluxes up to
10.5 L/m
2 /h and 5.37 L/m
2 /h, respectively. Furthermore,
they concluded with an economic analysis of FO coupled
with bioprocessing and proved the reduction cost in the final
product.
Shibuya et al. (2017) worked in a membrane process by
combining nanofiltration and FO to concentrate sugar with
the aim of bio-ethanol product from the liquid fraction of
rice straw. They found that the commercial NF membrane
known as “ESNA3” was more adequate for removal of
fermentation inhibitors (such as acetic acid) than the FO
membrane, whereas the commercial FO membrane
“TFC-ES” was more adequate for concentration of the
sugars than the NF membrane. As they found this, they
proposed the next process for the liquid fraction: (NF
(+H 2 O)) ! enzymatic hydrolysis ! FO concentration as
shown in Fig. 6.
4.2 Desalination of Drinking Water
Even though big efforts have been done to carry this application of FO to industrial levels, there are researchers
focused on developing new systems for water desalination in
order to optimize the global performance. Herein, some of
the most relevant works are briefly summarized (Blandin
et al. 2016; Valladares Linares et al. 2016; Fan et al. 2016;
Zhao et al. 2016). Figure 7 shows a general scheme for
desalination of drinking water.
First, Blandin et al. (2016) dedicated a very interesting
review to describe the state of the art of different systems for
combining water reuse and desalination through FO-RO
hybrid systems. FO-RO combination can be an alternative to
new desalination facilities or to implementation of
stand-alone water reuse schemes. They exposed that FO-RO
Fig. 5 Succinic acid concentration by forward osmosis. Modified after
Law and Mohammad (2018)
6
M. Rodríguez-Galán et al.
points embrace the four main industries in which forward
osmosis applications have a major impact—chemical
industry, desalination of drinking water, food industry and
pharmaceutical industry.
4.1 Forward Osmosis in Chemical Industry
Forward osmosis in chemical industry refers usually to the
wastewater treatment originated from different industries.
Many references have reported the implementation of FO
with different effluents, and some of them are explained in
this section (Soler-Cabezas et al. 2018; Law and Mohammad
2018; Cho et al. 2012; Kalafatakis et al. 2017; Shibuya et al.
2017).
Soler-Cabezas et al. (2018) corroborated the recovery of
nitrogen and phosphorus coming from the anaerobically
digested sludge concentrate through FO membranes. They
tested two draw solutions: a residual effluent from ammonia
elimination stage and brine from seawater. Moreover, they
tested two different FO membranes: CTA and Aquaporinbased membranes. They obtained a high nitrogen concentration with both membranes and draw solutions. They
concluded that the employment of ammonia absorption
effluent enhanced the nitrogen concentration.
Law and Mohammad (2018) investigated the role of the
FS pH of succinic acid concentration by FO as shown in
Fig. 5. They employed CTA membranes and examined both
the water flux and the reverse solute flux, using seawater as
draw solution. The results revealed that the pH affects the
FO performances. A strong effect was pointed out on the
succinate rejection for which nearly 100% rejections were
achieved at pH above its pKa = 2 value. With real seawater
as the draw solution, moderate water fluxes (<4 L m
−2 h
−1 )
were observed. They concluded that is possible to obtain
considerable water fluxes by swinging pH value.
Cho et al. (2012) focused on organic acid separation and
dewatering processes using nanofiltration and FO processes.
The organic acids are obtained during biomass decomposition under an anaerobic fermentation process, and their
accumulation hinders the microbial metabolism in the fermentation broths. Therefore, the authors of this investigation
proposed a novel research to remove organic acids through a
combination of nanofiltration and forward osmosis membranes. Using nanofiltration membranes, aqueous organic
acids can be selectively separated from pretreated fermentation feed solutions while other organics and many salts can
be rejected using these processes by varying pH conditions
in the feed. Finally, a low-energy-consuming forward
osmosis process was applied for dewatering in the aqueous
organic acid solutions to concentrate organic acid.
Kalafatakis et al. (2017) proposed crude glycerol and
enzymatically pretreated wheat straw as draw solution in
FO application against RO. This DS is generated as
second-generation product of bio-refineries. They applied
Aquaporin Inside™ TFC membranes, crude glycerol and
wheat straw hydrolysate and demonstrated water fluxes up to
10.5 L/m
2 /h and 5.37 L/m
2 /h, respectively. Furthermore,
they concluded with an economic analysis of FO coupled
with bioprocessing and proved the reduction cost in the final
product.
Shibuya et al. (2017) worked in a membrane process by
combining nanofiltration and FO to concentrate sugar with
the aim of bio-ethanol product from the liquid fraction of
rice straw. They found that the commercial NF membrane
known as “ESNA3” was more adequate for removal of
fermentation inhibitors (such as acetic acid) than the FO
membrane, whereas the commercial FO membrane
“TFC-ES” was more adequate for concentration of the
sugars than the NF membrane. As they found this, they
proposed the next process for the liquid fraction: (NF
(+H 2 O)) ! enzymatic hydrolysis ! FO concentration as
shown in Fig. 6.
4.2 Desalination of Drinking Water
Even though big efforts have been done to carry this application of FO to industrial levels, there are researchers
focused on developing new systems for water desalination in
order to optimize the global performance. Herein, some of
the most relevant works are briefly summarized (Blandin
et al. 2016; Valladares Linares et al. 2016; Fan et al. 2016;
Zhao et al. 2016). Figure 7 shows a general scheme for
desalination of drinking water.
First, Blandin et al. (2016) dedicated a very interesting
review to describe the state of the art of different systems for
combining water reuse and desalination through FO-RO
hybrid systems. FO-RO combination can be an alternative to
new desalination facilities or to implementation of
stand-alone water reuse schemes. They exposed that FO-RO
Fig. 5 Succinic acid concentration by forward osmosis. Modified after
Law and Mohammad (2018)
6
M. Rodríguez-Galán et al.