focuses on the optimizing surface wettability. For example,
omniphobic PVDF membrane had been fabricated in order
to minimize the wetting problem, and it shows that a slight
flux decline where the membrane will repel both water and
oil. This repletion is due to the grafting silica nano-particles
coated with fluoroalkylsilane (perfluorodecyltrichlorosilane).
Furthermore, Lokare et al. (2017) stated that membrane
properties were having a great influence on the flux permeation process of MD. Besides, membranes with highly
porous support are important for DCMD system. For all that,
MD technology is hardly to be commercialized due to high
energy consumption and the lack of commercially available
of high-performance membranes.
Pre-treatment (e.g., MF) (Kim et al. 2018) or posttreatment (e.g., crystallization) is required for PW treatment in
order to maintain the long-term operation of membranes
and/or minimize membrane fouling in the MD process. In
study conducted by Kim et al. (2017), it reported that total
recovery increased to 37.5% from 20 to 25% after removing
organic constituents like oil and grease prior to MD application. While Cho et al. (2018) had suggested that MD flux
decline could be avoided by performing a pre-treatments
process such as flocculation–sedimentation, vortex-based
anti-fouling membrane and flocculation–sedimentation-MF.
It shows that the flux reduction ratios were 3.6–6.9% and
8.9–16.2% for PP and PVDF membranes compared with
13.6% and 27.7% with raw PW wastewater, respectively,
after the pre-treatments. Moreover, Li et al. (2019) confirmed that sweeping air, elevated feed solution temperature
(from 59 to 65 °C), increased the VMD flux by 33%, 50%
and 19% and enhanced vacuum pressure (from 40 to
58 kPa), respectively. But, there is not necessary to having a
pre-treatment for FPW treatment by using DCMD, because
the TDS, TSS, oil and grease, and volatile organics had
minimal impact on DCMD membrane fouling and scaling.
Thermal-driven is also being a driven factor for membrane evaporation and pervaporation process. In term of heat
and mass transfer, membrane evaporation is similar to MD
system, but it is used for thermally sensitive solutions where
the water vapour will not be recovered at the permeate side
(Johnson et al. 2017). While, the pervaporation process is
using thermal-driven mechanism especially in the desalination technology. This pervaporation process is involving the
combination of membrane evaporation and permeation for
selective separation of aqueous mixtures. Pervaporation
offers the possibility of separating solutions, mixtures of
components with close boiling points or azeotropes that are
difficult to separate by distillation or other means. The first
systematic work on pervaporation was done by Binning and
co-workers at American Oil in the 1950s. The process was
not commercialized until 1982 when the first commercial
pervaporation plant, GFT (Gesellschaft für Trenntechnik
GmbH, Germany), was installed. This plant works in
separating water from alcohol solutions. Polyvinyl alcohol
composite membranes were being used in this plant. Distillation and pervaporation process were combined in this
plant to produce dry alcohol. Its working by removing the
water as permeate and producing pure ethanol contains of
1% of water without any azeotropic distillation problem.
About 50 such GFT plant had been installed at that time.
Another commercial pervaporation application is the
separation of dissolved volatile organic compound (VOCs)
from water, developed by Membrane Technology and
Research, Inc. This system was using hydrophobic composite membranes such as silicone rubber coated on a
microporous polyimide support membrane in a separation of
the organics and water. The difference in polarity between
organic solvents and water eases the separation process. The
first pilot plant was reported by Separec in 1988 in separating methanol from methyl t-butyl ether/isobutene mixtures. More recently, Exxon started a pervaporation pilot
plant for the separation of aromatic/aliphatic mixtures, using
polyimide/poly urethane block co-polymer membranes.
Furthermore, pervaporation process had demonstrated to be
achievable procedure in separating organic micro-pollutants
from water. Higher molecular size of 47–86% of aromatic
micro-pollutants could be rejected by hydrophilic pervaporative tubular membrane (Sule et al. 2016). Besides, graphene oxide/polyimide hollow fibre membranes are prepared
in study conducted by Huang and Feng (2018), for the
desalination of seawater by pervaporation. In result, an high
rate of water permeability and almost 99.8% of salt rejection
had been achieved at 90 °C operating temperature.
Last but not least, membrane crystallization (MCr) being
another process involves in thermal-driven concept. MCr is
an addition of the MD concept where membrane technology
and crystallization are working together in a single step
(Drioli et al. 2012). With the help of crystallizers, the hybrid
MD-crystallization technology succeeds in treating
wastewater that contains high content of saline water. As
compared to the single MD which having low recovery
(37.5%), MD-crystallization process could recover about
62.5% of the water by reducing inorganic loading in the
presence of crystallization. Additionally, Kim et al. (2018)
reported that MD-crystallization system is using in the Eagle
Ford PW where around 84% water success to be recovered
and leads to the solid production of 2.72 kg/m
2 per at
optimal operating conditions. Low energy consumed,
28.2 kWh/m
3 by using this MD-crystallization technology
under optimal operating conditions. Furthermore, with the
aid of osmotic pressure, MCr also has advanced capability in
extracting the freshwater and valuable components from
various streams without any limitations (Drioli et al. 2011).
In oilfield PW treatment, 16.4 kg per m
3 of high purity
(>99.9%) of crystal NaCl were recovered via MCr process
by using hollow fibre PP and PVDF membranes with a 37%
84
M. A. B. Pauzan et al.
omniphobic PVDF membrane had been fabricated in order
to minimize the wetting problem, and it shows that a slight
flux decline where the membrane will repel both water and
oil. This repletion is due to the grafting silica nano-particles
coated with fluoroalkylsilane (perfluorodecyltrichlorosilane).
Furthermore, Lokare et al. (2017) stated that membrane
properties were having a great influence on the flux permeation process of MD. Besides, membranes with highly
porous support are important for DCMD system. For all that,
MD technology is hardly to be commercialized due to high
energy consumption and the lack of commercially available
of high-performance membranes.
Pre-treatment (e.g., MF) (Kim et al. 2018) or posttreatment (e.g., crystallization) is required for PW treatment in
order to maintain the long-term operation of membranes
and/or minimize membrane fouling in the MD process. In
study conducted by Kim et al. (2017), it reported that total
recovery increased to 37.5% from 20 to 25% after removing
organic constituents like oil and grease prior to MD application. While Cho et al. (2018) had suggested that MD flux
decline could be avoided by performing a pre-treatments
process such as flocculation–sedimentation, vortex-based
anti-fouling membrane and flocculation–sedimentation-MF.
It shows that the flux reduction ratios were 3.6–6.9% and
8.9–16.2% for PP and PVDF membranes compared with
13.6% and 27.7% with raw PW wastewater, respectively,
after the pre-treatments. Moreover, Li et al. (2019) confirmed that sweeping air, elevated feed solution temperature
(from 59 to 65 °C), increased the VMD flux by 33%, 50%
and 19% and enhanced vacuum pressure (from 40 to
58 kPa), respectively. But, there is not necessary to having a
pre-treatment for FPW treatment by using DCMD, because
the TDS, TSS, oil and grease, and volatile organics had
minimal impact on DCMD membrane fouling and scaling.
Thermal-driven is also being a driven factor for membrane evaporation and pervaporation process. In term of heat
and mass transfer, membrane evaporation is similar to MD
system, but it is used for thermally sensitive solutions where
the water vapour will not be recovered at the permeate side
(Johnson et al. 2017). While, the pervaporation process is
using thermal-driven mechanism especially in the desalination technology. This pervaporation process is involving the
combination of membrane evaporation and permeation for
selective separation of aqueous mixtures. Pervaporation
offers the possibility of separating solutions, mixtures of
components with close boiling points or azeotropes that are
difficult to separate by distillation or other means. The first
systematic work on pervaporation was done by Binning and
co-workers at American Oil in the 1950s. The process was
not commercialized until 1982 when the first commercial
pervaporation plant, GFT (Gesellschaft für Trenntechnik
GmbH, Germany), was installed. This plant works in
separating water from alcohol solutions. Polyvinyl alcohol
composite membranes were being used in this plant. Distillation and pervaporation process were combined in this
plant to produce dry alcohol. Its working by removing the
water as permeate and producing pure ethanol contains of
1% of water without any azeotropic distillation problem.
About 50 such GFT plant had been installed at that time.
Another commercial pervaporation application is the
separation of dissolved volatile organic compound (VOCs)
from water, developed by Membrane Technology and
Research, Inc. This system was using hydrophobic composite membranes such as silicone rubber coated on a
microporous polyimide support membrane in a separation of
the organics and water. The difference in polarity between
organic solvents and water eases the separation process. The
first pilot plant was reported by Separec in 1988 in separating methanol from methyl t-butyl ether/isobutene mixtures. More recently, Exxon started a pervaporation pilot
plant for the separation of aromatic/aliphatic mixtures, using
polyimide/poly urethane block co-polymer membranes.
Furthermore, pervaporation process had demonstrated to be
achievable procedure in separating organic micro-pollutants
from water. Higher molecular size of 47–86% of aromatic
micro-pollutants could be rejected by hydrophilic pervaporative tubular membrane (Sule et al. 2016). Besides, graphene oxide/polyimide hollow fibre membranes are prepared
in study conducted by Huang and Feng (2018), for the
desalination of seawater by pervaporation. In result, an high
rate of water permeability and almost 99.8% of salt rejection
had been achieved at 90 °C operating temperature.
Last but not least, membrane crystallization (MCr) being
another process involves in thermal-driven concept. MCr is
an addition of the MD concept where membrane technology
and crystallization are working together in a single step
(Drioli et al. 2012). With the help of crystallizers, the hybrid
MD-crystallization technology succeeds in treating
wastewater that contains high content of saline water. As
compared to the single MD which having low recovery
(37.5%), MD-crystallization process could recover about
62.5% of the water by reducing inorganic loading in the
presence of crystallization. Additionally, Kim et al. (2018)
reported that MD-crystallization system is using in the Eagle
Ford PW where around 84% water success to be recovered
and leads to the solid production of 2.72 kg/m
2 per at
optimal operating conditions. Low energy consumed,
28.2 kWh/m
3 by using this MD-crystallization technology
under optimal operating conditions. Furthermore, with the
aid of osmotic pressure, MCr also has advanced capability in
extracting the freshwater and valuable components from
various streams without any limitations (Drioli et al. 2011).
In oilfield PW treatment, 16.4 kg per m
3 of high purity
(>99.9%) of crystal NaCl were recovered via MCr process
by using hollow fibre PP and PVDF membranes with a 37%
84
M. A. B. Pauzan et al.