499
Indonesian Journal of Science & Technology 8.
499-516 Indonesian Journal of Science & Technology Journal homepage: http://ejournal.
edu/index.
php/ijost/ Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber Membrane and Its Application Desalination of Wetland Saline Water via Pervaporation Mahmud1.
Muthia Elma1,*.
Aulia Rahma1.
Nurul Huda1.
Riani Ayu Lestari1.
Awali S.
Harivram1.
Erdina L.
Rampun1.
Mohd H.
Othman2.
Muhammad Roil Bilad3 Lambung Mangkurat University.
Banjarbaru.
Indonesia Advanced Membrane Technology Research Centre.
Universiti Teknologi Malaysia.
Johor.
Malaysia Department of Chemical and Process Engineering.
Universiti Brunei Darussalam.
Brunei Darussalam.
Correspondence: E-mail: melma@ulm.
ABSTRACT
Wetland water is opted as the source of domestic water supply when the availability of clean fresh water is scarce.
Wetland water requires proper treatment due to the high concentration of organic matter and high salinity, particularly in the dry season.
This research aims to synthesize, characterize, and investigate the performance of polyvinylidene fluoride (PVDF)-TiO2 hollow fiber membrane for wetland saline water desalination via pervaporation.
The PVDF-TiO2 hollow fiber membranes were fabricated through the dry wet spinning method under various air gaps .
, 15, and 20 c.
Then, the resulting membranes were tested in a pervaporation process at temperatures of 25, 40, and 60AC.
Results show that the incorporation of TiO2 into the PVDF matrix imparted hydrophilicity properties into the resultant The presence of TiO2 was confirmed by the TiO2 stretching vibration at 1640 cm-1 (FTIR) and the TiO2 phase at diffraction peaks at 25.
5 and 37A.
The membranes exhibited the highest water flux .
48 kg/m2.
and salt rejection (> 5%) at 40AC.
Overall, the developed PVDF-TiO2 hollow fiber membranes showed encouraging results and demonstrated their effectiveness for the desalination of wetland saline water.
A 2023 Tim Pengembang Jurnal UPI
ARTICLE INFO
Article History:
Submitted/Received 20 Jul 2023
First Revised 01 Sep 2023
Accepted 16 Oct 2023
First Available online 18 Oct 2023
Publication Date 01 Dec 2023
____________________
Keyword:
Desalination.
Dry wet spinning.
Hollow fiber membrane.
PVDF-TiO2.
Wetland saline water.
Mahmud et al.
Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 500
INTRODUCTION
South Kalimantan-Indonesia is located in the Southern part of Borneo, with a population of 4.
3 million, dominantly covered by tropical.
The wetland water is commonly used for domestic usage in remote coastal areas and households that are yet to receive clean water from the municipal water supply.
Fundamentally, direct consumption of wetland water is not advisable because it has poor quality, and frequently it becomes saline during the dry season (Elma.
Mustalifah et al.
, 2020.
Elma.
Riskawati et al.
, 2018.
Lestari et al.
, 2020.
Rahma.
Elma.
Mahmud.
Irawan et al.
, 2.
Wetland saline water contains high salt concentrations of 0.
2 wt% NaCl, which are almost equal to brackish and seawater salt concentrations (Rahma.
Elma.
Rampun, et al.
, 2.
Hence, a simple yet versatile treatment is required.
Different types of treatments have been explored for wetland saline water such as coagulation (Elma.
Rahma et al.
, 2020.
Mahmud et al.
, 2020.
Rampun.
Elma.
Syauqiah et al.
, 2.
These treatments enable to remove natural organic matter (NOM) and salinity (Elma.
Bilad et al.
, 2022.
Elma.
Ghani et al.
, 2022.
Elma.
Mujiyanti et , 2020.
Elma.
Pratiwi et al.
, 2022.
Elma.
Rahma et al.
, 2022.
Elma.
Rahma et al.
, 2020.
Mat Nawi et al.
, 2022.
Nawi et al.
, 2020.
Rahma.
Elma.
Aliah, et al.
, 2022.
Rahma.
Elma.
Pratiwi et al.
, 2020.
Rahma.
Elma.
Rampun et al.
, 2020.
Satria Anugerah et al.
Among these treatments, the pervaporation process provides interesting features of less thermal energy consumption compared to membrane distillation because it only requires vacuum conditions (Rampun.
Elma.
Rahma, et al.
, 2.
Previous studies employed inorganic membranes based on silica materials and removed up to 60% of NOM from wetland saline water (Elma et al.
Maulida et al.
, 2023.
Pratiwi et al.
Rahma et al.
, 2023.
Sari et al.
, 2.
The materials could operate with minimum issues of membrane scaling and fouling (Elma.
Mujiyanti et al.
, 2020.
Elma.
Rampun et al.
, 2.
Polyvinylidene fluoride (PVDF) is a commercial polymer typically used for the microfiltration membranes but has been used limitedly for water desalination (Li et al.
PVDF polymer is desirable since it provides .
good chemical resistance, .
chemical stability.
temperature stability.
mechanical strength (Deshmukh & Li.
Shi et al.
, 2.
PVDF has been explored for desalination applications due to its high selectivity to reject salt content (Fan & Peng, 2.
However, its inherent hydrophobic properties may cause fouling when used for the traditional pressuredriven filtration processes.
The application of TiO2 as an additive in polymeric membranes has been reported to enhance the membrane properties, i.
selectivity, permeability, and physical strength, whilst reducing the membrane fouling propensity (Dzinun et al.
, 2.
TiO2 has been chosen due to its low-cost, nontoxic, and commercially available.
It reduces the hydrophobicity and imposes anti-fouling properties on the resultant membranes (Parvizian et al.
, 2020.
Sun et al.
, 2.
However, those resultant membrane properties were found to be dependent on the membraneAos fabrication method.
For instance.
PVDF-TiO2 hollow fiber membranes fabricated using a wet-spinning method had a strong interaction between polymeric and inorganic networks due to the uniform dispersion of TiO2 within the polymeric The incorporation of TiO2 into the polymeric matrix increased the average pore size compared to the pristine PVDF membrane (Yu et al.
, 2.
The dry-wet spinning method is known in membrane fabrication because it has specific benefits such as simplicity, shortening time, and producing asymmetric cross-section In addition, the effect of air gap in DOI: https://doi.
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Volume 8 Issue 3.
December 2023 Hal 499-516 the dry-wet spinning method has been reported in previous studies.
The morphological analysis of PVDF membranes prepared under various air gaps .
, 20, 30 c.
was investigated, that the air gap affected the resulting membrane properties such as finger-like structure, membrane roughness, pore size distribution, porosity, hydrophobicity, and tensile strength.
Khulbe et al.
applied different air gaps from 10 to 90 cm and found their effect on the membrane roughness.
They found different roughness between the inner and outer surfaces of the hollow fiber membrane.
The air gap significantly affected the water flux membrane as well.
The water flux increased at higher air gaps, leading to an increase in membrane pore size.
Li et al.
investigated the performance of the PVA/PVDF membrane in the pervaporation desalination process at different operating temperatures .
-90AC) and feed salinities .
-250 g/L NaC.
The water flux was at 8.
6 L/m2h for 100 g/L NaCl at 80AC.
The loss of water flux occurred when treating a high solute concentration of 250 g/L NaCl.
The decline in water flux was mainly attributed to the concentration polarization during the pervaporation process.
Such findings concluded that the feed temperature and salinity concentration were crucial parameters in evaluating the pervaporation performance.
In other work, a composite hollow fiber membrane was synthesized by blending PVA and nano-TiO2.
Interestingly, the membrane could not reject NaCl and Na2SO4 .
norganic sal.
in the feed solution because of the Donnan effect between the hydroxyl group on the composite membrane surface with similar ionic states (Li et al.
, 2.
To our knowledge, the desalination of wetland saline water using PVDF/TiO2 hollow fiber membranes through pervaporation has not yet been reported.
This study aims to synthesize, characterize, and investigate the performance of PVDF-TiO2 hollow fiber membranes for wetland saline water The membranes were synthesized using the drywet spinning method at various air gaps .
, 15, 20 c.
to modulate the resultant membrane properties.
METHODS
Chemicals and Materials Wetland saline water was taken from Muara Halayung village.
Banjar District.
South Kalimantan-Indonesia in August 2020 during the dry season.
PVDF (Kynar 760 powder serie.
was selected as the base polymer.
TiO2 (Merc.
as the additive.
Dimethylacetamide (DMAc.
QReC) and ethanol as the solvent, demineralize water as the non-solvent, while epoxy resin (E30CL.
Loctite Corporation.
USA) as the module potting agent.
All chemicals, otherwise clearly specified, were used as analytical grade reagents.
Step-By-Step Method for Membrane Synthesis and Characterization The synthesis of PVDF-TiO2 hollow fiber membranes was done according to our earlier works (Kamaludin et al.
, 2.
, as detailed in the step-by-step method as PVDF polymer and TiO2 were dried in an oven at 50AC for 24 h to remove the Approximately 21 g of PVDF polymer was added into 152 mL of DMAc The mixture was stirred at 530 rpm at 70oC until homogeneous.
Then, 6 g of TiO 2 powder was added to the mixture and continuously stirred for 24 h.
The resultant dope solution was then cooled to room temperature and degassed in an ultrasonic water bath for 60 min.
Finally, the spinning of hollow fiber was performed by loading the degassed dope solution into the dope reservoir through a syringe pump and extruded by spinneret at an extrusion rate of 26 mL/min.
The air gap distances were varied by 10, 15, and 20 cm during the spinning The resultant membranes were characterized using Scanning Electron DOI: https://doi.
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Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 502 Microscope (SEM) analysis, contact angle, and Fourier Transform InfraRed (FTIR).
How to Evaluate the Pervaporation Performance The performance of the PVDF-TiO2 hollow fiber membrane was tested in the pervaporation set-up as illustrated in Figure The performance was assessed in the forms of permeate flux, salt rejection, and organic matter rejection.
The feed solutionAos temperature was varied between 25AC .
oom temperatur.
to 60AC at a fixed pervaporation duration of 20 minutes.
Permeate conductivity .
epresenting the solute concentratio.
and the absorbance of UV254 .
epresenting the NOM concentratio.
were measured using a conductivity meter and UV-Vis spectrophotometer, respectively.
The determined using the equation below:
ya= ycI= yco a OIy.
ayce Oe yayc.
y 100% .
Where ya is permeate flux .
g/m2.
, m is the mass of permeate .
retained in the cold trap.
A is the surface-active area .
, it is the time measurement .
, ycI is rejection (%).
Cf and Cp are the feed and permeate concentration .
t%) of solute or organic RESULTS AND DISCUSSION Characteristics of Wetland Saline Water The wetland saline water naturally formed a cloudy brown color caused by the appearance of NOM, as shown in Figure 2.
The NOM also represents a soluble and insoluble material that directly affects the water quality (Dayarathne et al.
, 2.
The presence of NOM can be proven by using the UV254 analysis.
Table 1 shows the inherent water quality of the wetland saline water used in this study.
The pH of wetland saline water was around 6.
6, still within the WHO standard limit .
However, the conductivity and the TDS parameters were higher than the WHO standard.
thus, the wetland saline water required further treatment before could be consumed.
Cold trap Thermometer N2 liquid Vacuum Valve Membrane Hotplate & stirrer Figure 1.
Illustration of pervaporation setup used for evaluating the membrane DOI: https://doi.
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Volume 8 Issue 3.
December 2023 Hal 499-516 Table 1.
The inherent water quality of wetland saline water taken in August 2020 at Muara Halayung village (GPS location: -3.
479779, 114.
Parameters Unit
Conductivity Total Dissolved Solid
UV254
ms/cm 1/cm Weeks i Average Standard 5 Ae 8 4 mS/cm Figure 2.
The sampling location .
ttached photograph pictur.
and the wetland saline water samples used as the feed for the pervaporation.
Membrane characteristics SEM was used as a tool to analyze the surface and cross-section microstructure and morphologies of the resultant PVDF-TiO2 Step-by-step analysis of the membrane microstructure based on the obtained SEM images is discussed as follows.
Based on Figure 3 .
, the cross-section images of the membrane can be observed.
has a macro void that resembles a finger-like structure combined with a sponge-like It is a type of asymmetric pore that is formed by the phase inversion method (Kingsbury & Li, 2009.
Wang et al.
, 2.
The macro void structures were formed close to the inner and outer membrane The sponge-like pores consisted of an interconnected network type and a closed-cell type within the entire membrane Such structure formation was attributed to the exchanging process between non-solvent and strong solvents during the phase separation as reported earlier (Tan & Rodrigue, 2.
The white spots visible in Figure 3.
, proved the presence of TiO2 embedded as part of the membrane matric.
The presence of TiO2 reduced the formation of finger-like pores massively, as discussed elsewhere (Kamaludin et al.
, 2.
TiO2 presence increases the viscosity of a dope polymer solution hence altering the path of polymersolvent-nonsolvent compositions during the phase inversion process.
The aggregation of TiO2 particles led to a rougher membrane surface for the PVDF-TiO2 membrane compared to the pristine PVDF membrane, as also found by others (Sakarkar et al.
, 2.
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Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 504 Air gap 15 cm Outer surface view Cross section view Finger-like view Air gap 10 cm 40 AAm 40 AAm 40 AAm Air gap 20 cm 1740 AAm 1980 AAm 2010 AAm 1380 AAm 1390 AAm 1170 AAm 5 mm 5 mm 6 AAm Mag.
5 mm 6 AAm 6 AAm Mag.
Mag.
Figure 3.
SEM images of the cross-section .
1-c1 and a2-c.
and surface .
3-c.
, showing the microstructure and morphology of PVDF-TiO2 membranes.
The air gap is one of the primary variables that influence membrane morphology.
The gravity forces of the falling film during the spinning process imposed elongational stress on the hollow fiber membrane in the air gap region during the dry-wet spinning process.
As the air gap increased, the membrane tended to elongate, followed by a decrease in diameter and fiber thickness.
Figure 3 .
shows the outer diameter (OD) of the membranes were 2010, 1980, and 1740 AAm for air gaps of 10, 15, and 20 cm, respectively.
Meanwhile, the inner diameter (ID) of the membranes were 1390, 1380, and 1170 AAm for the air gaps of 10, 15, and 20 cm.
Each membrane with variations of air gap has a thickness of 620, 600, and 570 Similar results were also found by Okubo et al.
and Abidin et al.
The shortest air gap distance produced the thickest membrane with the largest OD and the smallest ID attributed to the effect of die swell in the membrane polymers.
Die swell occurred because the material had elasticity .
, and experienced extrusion on the die channel when flew out through the After that, the polymers instantly swell because of their viscoelasticity properties (Peng et al.
, 2.
Such findings prove that the effect of gravity force on air gap impacts polymer deformation during the dry-wet spinning process (Chung et al.
The polymer has strong intermolecular At a certain level, it only deformed and did not break the interactions between molecules under stress.
This deformation caused the molecules in the polymer to find a new balance to maintain the intermolecular interactions (Khayet.
Therefore, it is possible to a form hollow fiber membrane with a smaller diameter and thickness by increasing the air DOI: https://doi.
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Volume 8 Issue 3.
December 2023 Hal 499-516 The air gap does not only affect the dimensions of the membrane but also affects the structure formed in the membrane Smaller air gaps tend to form fingerlike macro voids.
This kind of macro void is highly undesirable because it imparts a low mechanical strength in the resultant As the air gap increases, the macro void changes from finger-like to sponge-like.
This type is more desirable and has better mechanical properties.
Spongelike structures have a smaller void volume than finger-like structures (Gao, 2.
The membrane structure was denser in the more significant air gap than the smaller air gap as illustrated in Figure 3.
In summary, the membrane morphology was affected by two main mechanisms.
the orientation of the molecules on the membrane and elongation stress due to gravity effect on the air gap, and .
shear stress and elongation stress in the spinneret (Khayet, 2.
The hydrophilicity test was performed by the contact angle analysis.
The contact angle analysis quantifies the interfacial interaction between solids and liquids to determine the hydrophilicity of the membranes.
The membrane can be indicated as hydrophilic when the liquid spreads well on the membrane surface with a contact angle value below 90A (Law, 2.
The contact angle value () of the PVDFTiO2 membrane was 62o as shown in Figure PVDF is a polymer-based material frequently used in membrane fabrication.
has hydrophobic properties with a contact angle value of 90o (Zou et al.
, 2.
Meanwhile, pure TiO2 has excellent hydrophilic properties, outstanding chemical stability, and potential as an anti-fouling agent (Hong et al.
, 2.
Blending TiO2 particles into the polymer-based membrane matrix imparted hydrophilicity properties into the resultant material (Huang et al.
Myricq et al.
, 2015.
Qin et al.
, 2.
Such changes were attributed to TiO2 properties, which consisted of highly oxygenated hydrophilic functional groups Hong et al.
, .
that had a higher affinity towards water than the pristine PVDF membrane (Damodar et al.
, 2.
The FTIR spectra of the PVDF-TiO2 membrane are shown in Figure 5a.
A step-bystep analysis of the chemical bonds identified from the FTIR spectra is presented as follows.
FTIR analysis is a qualitative method to determine the functional groups composed within the membrane matrix (Sakarkar et al.
The fingerprint-like peaks appeared at the wavelength range from 700 to 1500 cm-1 and corresponded to the characteristic of PVDF functional groups, consisting of , , and crystalline phases.
The vibration bond found at peaks 763-766 (Medeiros et al.
Mun et al.
, 2.
, 795, 854, and 975 cm-1 is the characteristic peak of crystalline phase (Cai et al.
, 2.
The characteristic peak for the crystalline phase was observed at 1275 cm -1 (Cai et al.
, 2017.
Medeiros et al.
, 2.
The crystalline phase characteristic peak was also found at 1234 cm-1.
The peaks in the range of 860 Ae 900 and 1050 Ae 1200 cm-1 represented the combination of , , and crystalline phases, which were also reported elsewhere (Benz et al.
, 2002.
Cai et al.
, 2017.
Kaspar et , 2020.
Yoon et al.
, 2.
The absorption bands found at 820 Ae 860 and 1140 Ae 1280 cm-1 were characteristic of asymmetrical stretching and symmetrical stretching of CF2, respectively (Sakarkar et al.
, 2.
addition, the peaks 1403 cm-1 and 1640 cm -1 were attributed to AeCH2 from PVDF and AeOH from TiO2 stretching vibration (Bai et al.
Qin et al.
, 2015.
Yu et al.
, 2.
Furthermore, the absorption from 800 to 900 cm-1 represented a mixed band of AeCH2 rocking and AeCF2 asymmetric stretching in , , phases or a combination of the three phases (Cai et al.
, 2.
Figure 5.
represents the XRD spectra of the PVDF-TiO2 membranes in uncalcined and calcined conditions.
Step-by-step analysis of the membrane crystallinity identified from the XRD spectra is detailed as follows.
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Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 506 Figure 4.
Typical contact angle image of PVDF-TiO2 hollow fiber membrane.
CH2
Intensity .
Absorbance .
CF a TiO2
a b g
a b g
Uncalcined 100 oC
Uncalcined Calcined at 100 C
Calcined at 300 C
Wavenumber cm
2 (A)
Figure 5.
FTIR spectra and .
XRD spectra of the PVDF-TiO2 hollow fiber membrane in various conditions.
The peaks at around 18 and 21A belonged to the PVDF matrix that showed the appearance of crystalline phase and crystalline phase, respectively (Cai et al.
Kaspar et al.
, 2.
Meanwhile, the peaks at approximately 25 and 37A represented TiO2 particles, indicating that TiO2 retained its crystalline phase within the membrane matrix (Sakarkar et al.
, 2.
The XRD analysis confirmed that the phase dominated the crystal composition of the PVDF-TiO2 membrane.
It was proven by the distinct diffraction peak of crystalline phase compared to crystalline phase for the uncalcined and calcined membranes.
However, the diffraction peaks of and crystalline phases decreased significantly at 300AC.
Such changes could be attributed to the decomposition of the polymer materials at a higher temperature (Mun et al.
, 2.
The diffraction peaks at around 25.
5 and 37A indicated the TiO2 crystal remained in the membrane matrix and did not decompose at higher temperatures (Sakarkar et al.
, 2.
These findings were in tandem with the FTIR Pervaporation of Wetland Saline Water The PVDF-TiO2 membranes spun at different air gaps for desalination of varied feeds of wetland saline water is shown in Figure 6.
The water fluxes of the PVDF-TiO2 membrane spun at air gaps 10, 15, and 20 cm were 10.
kg/m2.
h, respectively for pure water The result demonstrated that DOI: https://doi.
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Volume 8 Issue 3.
December 2023 Hal 499-516 the pure water permeation increased by decreasing the air gap from 20 to 10 cm.
It is due to the longer air gapAos length that led to the formation of a thinner separation layer, as discussed elsewhere (Yu et al.
, 2.
similar trend was also observed at different feed water conditions, i.
, brackish, saline wetland, seawater, and brine water (Figure For instance.
PVDF-TiO2 spun at a 10 cm air gap recorded the highest permeate flux for brackish water, surpassed that of air gap at 15 and 20 cm by 34.
8 and 70%.
The air gap has a crucial effect on the cross-section morphology and performance of the PVDF-TiO2 hollow fiber membrane.
Increasing air gap resulted in low permeability and high solute rejection (Gao.
It can be well correlated with the morphology of the membrane.
As the fingerlike pores reduced at longer air gap length, the permeate fluxes decreased (Zakria et al.
This is corroborated by the SEM crosectional images shown in Figure 3c1 which incorporated a denser sponge-like structure consisting of a small amount of finger-like pores within the membrane matrix.
Salt rejection (%) Brackish water Saline wetland water Seawater Brine water Pure water Brackish water Saline wetland water Seawater Brine water Permeate flux .
Air gap .
Figure 6.
Effect of air gap during the dry-wet spinning on the pervaporation performance of PVDF-TiO2 hollow fiber membranes treating various feeds.
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Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 508 The permeation performances of PVDFTiO2 hollow fiber membrane spun at 10 cm for multiple saline water feed desalination were in the order of brackish > saline wetland > sweater > brine water.
Reduction in permeate fluxes as the feed saline concentration increased from 0.
to 5 wt% NaCl .
was attributed to the salt concentration polarization effect (Elma et al.
, 2.
The driving force for salt diffusion increased across the membrane due to the increase in feed salt concentration at the membrane surface (Elma et al.
, 2.
Moreover, salt rejections of 90.
6-99, 92.
8, and 96-99.
7% were recorded for membranes spun at air gaps of 10, 15, and 20 cm in multiple feed water conditions.
As increasing air gap length from 10 to 20 cm, the salt rejection also The air gap length allows the membrane morphology to restrain the NaCl molecule via its thinner and denser fingerlike structure (Khayet, 2.
In addition, the longer length of the air gap enables modulation of the distribution of TiO2 nanoparticles within the outer surface membrane layer, which causes the membrane to become hydrophilicity and improves salt rejection (Yaacob et al.
, 2.
Salt rejection was generally very high with more than 91% for all air gaps and feed water The PVDF-TiO2 membrane was also tested at various feed temperatures to investigate the pervaporation performance.
They were permselectivity as shown in Figure 7.
It shows the effect of temperature on the water flux at various feed water conditions at a fixed pervaporation time of 20 minutes.
The water flux of wetland saline water was higher than the feed with 3.
5 wt% NaCl solution .
imulating sea wate.
but was lower than the feed with 0.
3 wt % NaCl solution.
The highest water flux of NaCl 0.
3 wt%, wetland saline water, and NaCl 3.
5 wt% solutions were 15.
19, 13.
64, and 8.
kg/m2.
h at 60 AC, respectively.
The finding could be attributed to the effect of different salt concentrations in each feed.
High salt concentration led to the flux decline caused by concentration polarization (Elma et al.
The pervaporation process of wetland saline water was previously using an interlayer-free-silica-pectin membrane.
was found that the water fluxes of the same wetland saline water .
sing pectin concentrations of 0.
5 and 2.
5 wt% as templat.
78 and 3.
22 kg/m2.
Thus, the pervaporation process using PVDF-TiO2 hollow fiber membrane had excellent performance because it produced a higher water flux than interlayer-free-silica-pectin The decline of salt rejection in permeate was observed with the increase in the feed The decrease of salt rejection followed the order of 60 > 40 > 25CC.
Such findings can be well correlated with the condition caused by a random movement of polymer chains under the effect of The polymer chain movement .
led to the enlargement of membrane pores, which facilitated the diffusion of salt molecules freely through the membrane (Jyoti et al.
, 2.
The salt rejections for all feed temperatures were higher than 90%, and the highest was 99.
at 25CC for the wetland saline water.
This result is similar to the previous work conducted by other researchers.
Total dissolved solid (TDS) removal and UV254 absorbance were measured to determine the membraneAos ability to remove the dissolved solids and organic impurities as shown in Figure 8.
All the TDS removal of wetland saline water at various feed water conditions showed higher than 99.
This result indicated that the pervaporation process using PVDF-TiO2 hollow fiber membrane successfully removed the dissolved solid in wetland saline water.
UV254
absorbance of the wetland saline water at 25, 40, and 60CC were 98.
58, 89.
87, and 87.
UV254 absorbance decreased DOI: https://doi.
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December 2023 Hal 499-516 along with the increase in the feed temperature originating from the presence of organic foulant found on the membrane The wetland saline water had a brown color and high NOM constituted of high humic materials (Mahmud & Noor.
The high concentration of polarization of NOM in water contributed to membrane fouling (Goh et al.
, 2.
UV254 absorbance was lower than TDS rejection because the wetland saline water contained high humic material which caused the membrane fouling Flux .
g m h ) Pure water Brackish water Saline wetland water Seawater Brackish water Saline wetland water Seawater Rejection (%) during the pervaporation process, while TDS rejection was not affected by the presence of NOM.
The performance of several types of membranes applied for wetland saline water desalination is summarized in Table 2.
The developed PVDF-TiO2 hollow fiber showed decent performance at moderate feed It was proven by the higher water flux value than previous reportswith the salt rejection of more than 99.
25 30 35 40 45 50 55 60 25 30 35 40 45 50 55 60
Feed temp.
C) Feed temp.
( C)
Figure 7.
Water flux .
and salt rejection .
of PVDF-TiO2 hollow fiber membrane at various feed temperatures.
Rejection (%) UV254
TDS
Temperature ( C) Figure 8.
Effect of the feed temperature variations .
AC, 40AC, and 60AC) on TDS removal and UV254 absorbance of wetland saline water.
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Step-by-Step Fabrication of PVDF-TiO2 Hollow Fiber A | 510 Table 2.
Comparison of of several types of membranes used for desalination of wetland saline water.
Type of PVDF-TiO2 hollow fiber CTA/Al2O3 hollow fiber membrane Silica-Pectin Feed Temperature Feed Types (CC) Wetland saline water Wetland saline water Wetland saline water Water Flux .
g/m2.
Salt Rejection (%) >99.
Coagulation (Silica-Pecti.
Wetland
saline water
Alumina hollow
fiber membrane Wetland
saline water
CONCLUSION
PVDF-TiO2 hollow fiber membrane was successfully prepared and characterized.
The results show that membrane morphology (OD.
ID, and thicknes.
decreased with the increasing the air gap.
The resultant membrane imparted hydrophilic properties as TiO2 particles blended well within the membrane matrix as visually observed from the SEM images.
The presence of TiO2 was confirmed through the observed diffraction peaks at 25.
5 and 37C.
The highest water flux and salt rejection were observed at 7.
kg/m2.
h and > 99.
5 wt% at 40CC with a decent percentage of TDS and NOMs Overall, it can be concluded that the PVDF-TiO2 hollow fiber membrane showed the potential to treat wetland saline water via the pervaporation process.
ACKNOWLEDGMENT
References This research (Prihatiningtyas et , 2.
(Rahma.
Elma.
Mahmud.
Irawan, et al.
, 2.
(Rahma.
Elma.
Mahmud.
Irawan et al.
, 2.
(Fang et al.
, 2.
(AMTEC).
University Teknologi Malaysia (UTM) and Materials and Membranes Research Group (M2ReG).
Lambung Mangkurat University for the facilities.
Also, thanks to the oil palm research grant 2022 [PRJ-371/DPKS/2.
and the Oil Palm Plantation Fund Management Agency Republic of Indonesia for the financial Muthia Elma also thanks to Applied Research Universities Grant .
/E5/PG.
PL/2.
Thesis Grant .
/E5/PG.
PL/2023 the Ministry of Research and Technology/National Research and Innovation Agency, the Ministry of Education and Culture of the Republic of Indonesia.
AUTHORSAo NOTE The authors declare that there is no conflict of interest regarding the publication of this article.
The authors confirmed that the paper was free of plagiarism.
Muthia thanks to the Advanced Membrane Technology Research Centre DOI: https://doi.
org/10.
17509/ijost.
p- ISSN 2528-1410 e- ISSN 2527-8045 511 | Indonesian Journal of Science & Technology.
Volume 8 Issue 3.
December 2023 Hal 499-516
REFERENCES