daryoush emadzadeh - Academia.edu (original) (raw)

Papers by daryoush emadzadeh

Research paper thumbnail of Efficiency evaluation of titanium oxide nanocomposite membrane in adsorption of chromium from oil effluents

Environmental Monitoring and Assessment

Research paper thumbnail of Synthesis of Novel Hybrid NF/FO Nanocomposite Membrane by Incorporating Black TiO2 Nanoparticles for Highly Efficient Heavy Metals Removal

International Journal of Environmental Research, 2021

In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the ai... more In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving the efficiency of heavy metal removal. Here, black TiO2 nanoparticles (BNPs) were synthesized first and embedded in the polyamide (PA) active layer of TFC NF membrane to rectify the performance of membranes. The resulting TFN NF membranes were then tested in hybrid NF/FO system properly. The presence of BNPs was confirmed with XPS and FTIR, while the morphological alterations in the synthetized membranes were characterized using FESEM and AFM. Nanofiltration membrane performance was examined using multivalent ions such as of MgSO4, Na2SO4, CaCl2, and NaCl monovalent ion. We demonstrated that the addition of BNPs led to a significant decrease in surface roughness and hydrophilicity, showing a further reduction with increased concentrations of BNPs. In addition, TFC membrane showed a water flux of 25 L/m2h compared to 39, 41, and 66 L/m2h for TFN0.01, TFN0.05, and TFN0.1 membranes, respectively. We also showed that under the FO process, TFN membrane demonstrated the best performance with regards to heavy metal rejection and the highest Cr (III) and Pb (II) rejection was shown in TFN0.05 under the FO process. The ideal heavy metal rejections and acceptable water flux indicate the potential of these developed membranes under FO process for the removal of heavy metals from wastewater. In this study, a hybrid of Nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving heavy metals removal efficiency. In this situation where black TiO2 nanoparticles (BNPs), in fact, were synthesized firstly and then embedded in the polyamide (PA) active layer of TFC NF membrane to rectified membrane performances. Polysulfone (PSF) Udel P-3500 in pellet form (Solvay Advanced Polymers), dimethylacetamide (DMAC, N99.5%, Merck) as solvent and polyvinylpyrrolidone (PVP K30, Sigma-Aldrich) and 1- methyl-2-pyrrolidinone (NMP, Sigma-Aldrich) as additive were employed for membrane substrate synthesis. Substrate membrane was synthetized with dope solution that was made up of 17.5% PSF, 0.5% PVP and 82% DMAC. The top active layer of TFN membrane was formed by interfacial polymerization on the surface of a pre-cast PSF substrate. In the present work, cyclohexane was used as the organic solvent for better dispersion of BNPs. BNPs were added into cyclohexane containing TMC monomer. The mixture was then sonicated for 3 h to avoid the nanoparticle agglomeration. We also determined the zeta potential of TFC and TFN. membrane fabricated with BNP demonstrated a more negative zeta potential value compared to the pristine TFC membrane due to the increased number of oxygen-containing functional groups on the membrane surface. In this study, a hybrid of Nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving heavy metals removal efficiency. In this situation where black TiO2 nanoparticles (BNPs), in fact, were synthesized firstly and then embedded in the polyamide (PA) active layer of TFC NF membrane to rectified membrane performances. Polysulfone (PSF) Udel P-3500 in pellet form (Solvay Advanced Polymers), dimethylacetamide (DMAC, N99.5%, Merck) as solvent and polyvinylpyrrolidone (PVP K30, Sigma-Aldrich) and 1- methyl-2-pyrrolidinone (NMP, Sigma-Aldrich) as additive were employed for membrane substrate synthesis. Substrate membrane was synthetized with dope solution that was made up of 17.5% PSF, 0.5% PVP and 82% DMAC. The top active layer of TFN membrane was formed by interfacial polymerization on the surface of a pre-cast PSF substrate. In the present work, cyclohexane was used as the organic solvent for better dispersion of BNPs. BNPs were added into cyclohexane containing TMC monomer. The mixture was then sonicated for 3 h to avoid the nanoparticle agglomeration. We also determined the zeta potential of TFC and TFN. membrane fabricated with BNP demonstrated a more negative zeta potential value compared to the pristine TFC membrane due to the increased number of oxygen-containing functional groups on the membrane surface.

Research paper thumbnail of Integration of Porous Nanomaterial-Infused Membrane in UF/FO Membrane Hybrid for Simulated Osmosis Membrane Bioreactor (OsMBR) Process

Membranes

This study explored the use of a combination of hydrothermal and sol–gel methods to produce porou... more This study explored the use of a combination of hydrothermal and sol–gel methods to produce porous titanium dioxide (PTi) powder with a high specific surface area of 112.84 m2/g. The PTi powder was utilized as a filler in the fabrication of ultrafiltration nanocomposite membranes using polysulfone (PSf) as the polymer. The synthesized nanoparticles and membranes were analyzed using various techniques, including BET, TEM, XRD, AFM, FESEM, FTIR, and contact angle measurements. The membrane’s performance and antifouling properties were also assessed using bovine serum albumin (BSA) as a simulated wastewater feed solution. Furthermore, the ultrafiltration membranes were tested in the forward osmosis (FO) system using a 0.6-weight-percent solution of poly (sodium 4-styrene sulfonate) as the osmosis solution to evaluate the osmosis membrane bioreactor (OsMBR) process. The results revealed that the incorporation of PTi nanoparticles into the polymer matrix enhanced the hydrophilicity and s...

Research paper thumbnail of Fabrication and evaluation of nanofiltration membrane coated with amino-functionalized graphene oxide for highly efficient heavy metal removal

International Journal of Environmental Science and Technology, 2021

In this study, two different methods were used to introduce functionalized graphene oxide (GO) on... more In this study, two different methods were used to introduce functionalized graphene oxide (GO) onto the surface of nanofiltration (NF) membrane to improve its performance for heavy metal removal. The first method was based on coating in which the surface of NF membrane was coated with cross-linked GO, while the second method was introducing GO into monomer solution during interfacial polymerization. The efficiency of different methods was then compared by characterizing membrane physiochemical properties, as well as separation performance. With regard to performances, the water flux of TFN-i2 membrane (with GOs incorporated into thin layer) was reported to be 95 L/m2 h compared to 75 L/m2 h found in the TFN-c2 membrane (with GOs coated on the surface) at 8 bar. Both modified membranes exhibited higher water flux than the control membrane without GO incorporation (40 L/m2 h). Although the water flux of TFN-c2 membrane was lower, it achieved higher cobalt removal (97%) than that of TFN-i2 membrane (73%) due to its higher negative surface charge that improved separation via the Donnan exclusion effect.

Research paper thumbnail of Synthesis, modification and optimization of titanate nanotubes-polyamide thin film nanocomposite (TFN) membrane for forward osmosis (FO) application

Chemical Engineering Journal, 2015

h i g h l i g h t s Self-synthesized amino-functionalized TNTs with unique characteristics for TF... more h i g h l i g h t s Self-synthesized amino-functionalized TNTs with unique characteristics for TFN FO membrane. Synthesis of novel TFN FO membrane with greater water flux and lower reverse draw solute. Covalent bonding between nanotubes and PA layer improved separation properties of TFN membrane.

Research paper thumbnail of Effect of air-gap length on carbon dioxide stripping performance of a surface modified polysulfone hollow fiber membrane contactor

RSC Adv., 2014

Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps t... more Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps to evaluate CO 2 stripping from aqueous DEA solution and water. The fabricated membranes were firstly subjected to different characterization methods such as contact angle and liquid entry pressure measurement to evaluate the membrane's hydrophobicity and wetting resistance, respectively. To determine pore size and effective porosity of the membranes, a pure helium permeation test was performed. Morphological study of the membranes was conducted by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A CO 2 stripping test was carried out to investigate the effects of operating variables such as liquid and gas velocity, temperature and DEA concentration on the CO 2 stripping flux. It was found that the increase of liquid velocity resulted in enhanced CO 2 stripping flux. On the other hand, the increase in gas velocity did not exert significant influence on the stripping flux. The increase in temperature and DEA concentration both enhanced the stripping flux. Lastly, it was concluded that the hollow fibers spun in this work at a 15 cm air-gap could achieve the best stripping flux among all the membranes fabricated so far for CO 2 stripping.

Research paper thumbnail of Carbon dioxide stripping from water through porous polysulfone hollow fiber membrane contactor

Separation and Purification Technology, 2013

Carbon dioxide (CO 2) stripping from water was conducted through the porous asymmetric polysulfon... more Carbon dioxide (CO 2) stripping from water was conducted through the porous asymmetric polysulfone (PSf) hollow fiber membrane contactor. The effect of the liquid and gas flow rates on the stripping performance, the liquid phase CO 2 concentration and the CO 2 stripping efficiency of the membrane module and the effect of liquid phase temperature on CO 2 stripping flux were studied. The experimental results showed that the stripping gas velocity had a minor effect on the CO 2 desorption flux while the increase in the liquid velocity could enhance CO 2 desorption flux in the gas stripping membrane contactor. By increasing liquid flow rate to 200 ml/min, the maximum CO 2 stripping efficiency of almost 66% was achieved. Enhancement of liquid flow rate from 50 to 200 ml/min increased the CO 2 flux around 482%. It was found that the CO 2 stripping flux was significantly affected by the liquid phase temperature. By increasing liquid temperature from 80 to 90°C, the CO 2 stripping flux increased from 1.3 Â 10 À4 to 4.9 Â 10 À4 mol m À2 s À1 at liquid velocity of 200 ml min À1. Hence, the higher stripping efficiency can be achieved by applying the higher liquid flow rate in the membrane contactor module. As well, the liquid phase temperature is a key parameter that needs to be controlled.

Research paper thumbnail of A novel thin film nanocomposite reverse osmosis membrane with superior anti-organic fouling affinity for water desalination

Desalination, 2015

ABSTRACT In this work, titanate nanotubes (TNTs) were self-synthesized and amino functionalized t... more ABSTRACT In this work, titanate nanotubes (TNTs) were self-synthesized and amino functionalized to produce titanate nanotubes (NH2-TNTs) for thin film nanocomposite (TFN) reverse osmosis (RO) membrane fabrication. The novel RO membranes were fabricated by embedding NH2-TNTs of different quantities into polyamide (PA) layer. The nanotubular morphology of NH2-TNTs was studied using TEM while FTIR was employed to confirm the reaction of TNTs with [1-(2-amino-ethyl)-3-aminopropyl] trimethoxysilane. The effect of NH2-TNTs on the PA layer of TFNwith respect to surfacemorphology, separation performance and antifouling properties was thoroughly investigated and discussed. The presence of NH2-TNTs in PA layer was verified using XPS while the “leaflike” outgrowth morphology of PA layer was observed using FESEM. Results showed that the TFN membrane with 0.05% NH2-TNTs embedded was the most promising membrane as it exhibited 93% higher water flux than the control thin film composite (TFC) membrane, without compensating NaCl rejection. In terms of organic fouling tendency, the TFN0.05 membrane also showed higher tolerance compared to the controlmembrane during RO process. Furthermore, as high as 94% of the water flux of TFN0.05 was able to retrieve by a simple water rinse process, which suggests that organic fouling in TFN0.05 is highly reversible.

Research paper thumbnail of SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell

Journal of Chemical Technology & Biotechnology, 2015

Research paper thumbnail of Power generation and wastewater treatment using a novel SPEEK nanocomposite membrane in a dual chamber microbial fuel cell

International Journal of Hydrogen Energy, 2015

In this paper, the performance of two common and two self-fabricated proton exchange membranes we... more In this paper, the performance of two common and two self-fabricated proton exchange membranes were compared. Nafion 112 and Nafion 117, which are two of the most common proton exchange membranes that can be used in all fuel cell systems, were compared to SPEEK and SP/CC/TAP. The results showed that at lower COD such as 2000 mg/l, Nafion 117 has the highest performance in terms of power production and COD removal, while once the COD of wastewater goes up to 5000 mg/l, SP/CC/TAP has approximately the same performance as Nafion 117. The membranes were characterized by FESEM, while the degree of sulfonation was measured by NMR. The oxidation activity of microorganisms was measure by cyclic voltammetry (CV). Also, the attachment of bacteria onto the anode electrode was observed by SEM, which showed that different bacteria from the media with a mixed culture inoculum had attached to the anode electrode.

Research paper thumbnail of Effect of SMM concentration on morphology and performance of surface modified PVDF hollow fiber membrane contactor for CO2 absorption

Separation and Purification Technology, 2013

Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a dry-... more Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a dry-wet phased inversion process. Surface modifying macromolecules (SMMs) (0, 2, 4 and 6 wt.%) were used as additives in the spinning dope. During phase inversion SMM migrates to the membrane surface, resulting in different surface morphology and surface chemistry. The surface modified PVDF membranes showed the larger pore size, higher gas permeance, effective surface porosity, contact angle and overall porosity but lower critical water entry pressure compared to the PVDF hollow fiber membrane without SMM. The performance of the surface modified membrane in contactor application for physical CO 2 absorption was investigated by the fabricated gas-liquid membrane contactor module, where distilled water was used to dissolve CO 2. It was found that the liquid phase resistance was dominant in the absorption experiment. The results show that the surface modified PVDF membrane has a higher performance compared to control PVDF membrane. By increasing SMM concentration in the spinning dope, the CO 2 absorption flux increased significantly. With the membrane prepared from 6 wt.% of SMM in the spinning dope, a maximum CO 2 absorption flux of 5.4 Â 10 À3 mol/m 2 s was achieved at 300 ml min À1 of absorbent flow rate, which was almost 650% more than the fabricated membrane without SMM.

Research paper thumbnail of Synthesis and characterization of thin film nanocomposite forward osmosis membrane with hydrophilic nanocomposite support to reduce internal concentration polarization

Journal of Membrane Science, 2014

Realizing that one of the most important challenges in the forward osmosis (FO) membrane is inter... more Realizing that one of the most important challenges in the forward osmosis (FO) membrane is internal concentration polarization (ICP), thin film nanocomposite (TFN) membranes were prepared by incorporating different loadings of titanium dioxide (TiO 2) nanoparticles (ranging from zero to 0.90 wt%) into the polysulfone (PSf) substrate in order to reduce ICP. The nanocomposite substrates prepared were characterized with respect to hydrophilicity, overall porosity, surface roughness and cross-sectional morphology by different methods. Results revealed that both hydrophilicity and porosity of the substrate were increased upon addition of TiO 2 nanoparticles. Moreover, a large number of finger-liked macrovoids were developed by increasing the loading of TiO 2 nanoparticles, leading to enhancement in water permeability. As for the FO performance tested at AL-FS orientation and with DI water as feed and 0.5 M NaCl as draw solution, the TFN membrane prepared using PSf substrate embedded with 0.60 wt% TiO 2 nanoparticles (designated as TFN0.60) exhibited the most promising result by showing water flux of 18.81 L/m 2 .h, i.e. 97% higher than the control TFC membrane prepared by substrate without TiO 2 incorporation (designated as TFC), with no significant change in reverse solute flux. Compared to the control TFC membrane, the FO water flux of TFN0.60 was also reported to increase significantly from 4.2 to 8.1 L/m 2 .h (AL-FS orientation) and 6.9 to 13.8 L/m 2 .h (AL-DS orientation) when seawater was used as feed solution and 2 M NaCl was used as draw solution. The increase in water flux can be attributed to the decrease in structural parameter (S value = 0.39 mm), mainly due to the formation of finger-liked macrovoids that connect the top and bottom layer of the substrate and reduce the tortuosity, resulting in decreased ICP. Although further increasing TiO 2 nanoparticles loading to 0.90 wt% could increase membrane water permeability, the FO performance was compromised by a significant increase in reverse solute flux. To the best knowledge of the authors, this is the first report on TFN membrane using PSf-TiO 2 nanocomposite substrate for FO applications.

Research paper thumbnail of Synthesis of thin film nanocomposite forward osmosis membrane with enhancement in water flux without sacrificing salt rejection

Desalination, 2013

ABSTRACT In this study, thin film nanocomposite (TFN) membrane was developed using novel polysulf... more ABSTRACT In this study, thin film nanocomposite (TFN) membrane was developed using novel polysulfone–titanium dioxide (PSf–TiO2) nanocomposite substrate. The effects of TiO2 on the PSf substrate morphologies, hydrophilicity and water permeability were investigated and discussed. The results revealed that the hydrophilicity and the porosity of the substrate were improved upon the TiO2 addition, leading to significant enhancement in water flux. TFN membrane was then fabricated by establishing a polyamide layer made of 1,3-phenylendiamine and 1,3,5-benzenetricarbonyl trichloride monomers over the surface of the modified substrate. Compared with the typical TFC and commercial CTA membranes, the TFN membrane prepared always demonstrated much higher FO water flux without showing a significant increase in reverse solute flux when tested under same conditions. When tested in AL–FS orientation using 0.5 M NaCl as a draw solution and 10 mM NaCl as feed solution, the water flux of the TFN membrane was ∼ 120% and ∼ 87% higher than that of the commercial membrane and typical TFC membrane, respectively. The water flux of the TFN membrane was also reported to be much higher under prolonged filtration time, mainly due to the improved properties of substrate upon addition of TiO2.

Research paper thumbnail of A novel thin film composite forward osmosis membrane prepared from PSf–TiO2 nanocomposite substrate for water desalination

Chemical Engineering Journal, 2014

ABSTRACT In this work, polysulfone (PSf)–titanium dioxide (TiO2) nanocomposite substrates were pr... more ABSTRACT In this work, polysulfone (PSf)–titanium dioxide (TiO2) nanocomposite substrates were prepared by incorporating different amounts of TiO2 nanoparticles (ranging from zero to 1 wt%) into PSf matrix. The nanocomposite substrates so prepared were then characterized with respect to hydrophilicity, overall porosity, surface roughness and cross-sectional morphology. It was found that both hydrophilicity and porosity of the substrate were increased upon addition of TiO2. In addition, long finger-like structures were developed by increasing the TiO2 loading, leading to water permeability enhancement. In order to fabricate thin film nanocomposite (TFN) membranes for forward osmosis (FO) application, a thin polyamide layer was formed by interfacial polymerization of 1,3-phenylendiamine and 1,3,5-benzenetricarbonyl trichloride on the top surface of PSf–TiO2 nanocomposite substrates. Under the conditions for FO performance evaluation (10 mM NaCl concentration in feed solution, 0.5 and 2.0 M NaCl concentration in draw solution, and both active layer facing the feed solution (AL–FS) and active layer facing the draw solution (AL–DS) orientations), the TFN membrane prepared using PSf substrate embedded with 0.5 wt% TiO2 nanoparticles (denoted as TFN0.5) exhibited the most promising results by showing high water permeability and low reverse solute flux. In comparison with control TFC membrane, the water flux of TFN0.5 membrane was improved by 86–93%, depending on the membrane orientation and draw solution concentration. The increase in water permeability can be attributed to decrease in structural parameter which resulted in decreased internal concentration polarization (ICP). Although further increase in TiO2 nanoparticles loading to 0.75 and 1 wt% could result in higher water permeability, their FO performances were compromised by a significant increase in reverse solute flux. Based on the results obtained in this work, it can be concluded that adding an appropriate amount of TiO2 nanoparticles into PSf substrate could potentially improve the performance of TFC membrane during FO applications.

Research paper thumbnail of Study on CO2 stripping from water through novel surface modified PVDF hollow fiber membrane contactor

Chemical Engineering Journal, 2014

ABSTRACT Graphical abstract Schematic of CO2 stripping mechanism through gas–liquid membrane cont... more ABSTRACT Graphical abstract Schematic of CO2 stripping mechanism through gas–liquid membrane contactor.

Research paper thumbnail of Influence of air-gap length on CO2 stripping from diethanolamine solution and water performance of surface modified PVDF hollow fiber membrane contactor

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2018

Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air... more Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air-gaps (o to 20 cm) and used for CO2 stripping from aqueous DEA solution and water. The manufactured fibers were firstly subjected to various characterization tests such as contact angle and critical water entry pressure measurement to evaluate the HF hydrophobicity and wetting resistance, respectively. The pure helium permeation experiments were also conducted to obtain membrane pore size and effective porosity. Morphology of the HFs was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The SEM images showed that both outer and inner diameters of HFs decreased significantly by increasing air-gap length which mainly because of elongation of HF caused by gravity while travelling through the air-gap. Also, the gradual decrease in roughness on the external surface of the produced HFs was observed from the AFM images. It was found that the increase of liqui...

Research paper thumbnail of Mini Review on the Effects of Concentration Polarization in Forward Osmosis and Pressure-retarded Osmosis Processes

Extended Abstract Discharge of water from the boundary layer of the thin film composite membrane ... more Extended Abstract Discharge of water from the boundary layer of the thin film composite membrane can unbalance the concentration of solution at the membrane–feed interface and the bulk solution. This phenomenon is known as concentration polarization, and is common in pressure-driven membrane processes, particularly in reverse osmosis (RO) and nanofiltration (NF), but also in emerging forward osmosis (FO) and pressure retarded osmosis (PRO) processes. There are two types of concentration polarization, external (ECP) and internal (ICP). The effect of concentration polarization is always to decrease the membrane productivity (water flux) and selectivity (salt rejection); in other words, it undermines membrane performance regardless of the process. The ECP can occur at both interfaces of a membrane and can be dilutive or concentrative. However, it can be mitigated by promoting turbulence at a fluid-membrane interface. On the other hand, the ICP, which also can be dilutive or concentrati...

Research paper thumbnail of A Review on Mass Transport Phenomena and Factors Affecting the Performance of Thin Film Composite Membrane during Engineered Osmosis Process

Engineered osmosis (EO) is an osmotically driven membrane process that takes advantage of the osm... more Engineered osmosis (EO) is an osmotically driven membrane process that takes advantage of the osmotic pressure gradient to drive water across the semi-permeable membrane from the feed solution (low osmotic pressure) to the draw solution (high osmotic pressure). In the last decade, EO membranes have found various applications in wastewater treatment, seawater/brackish desalination, food processing and power generation. In this paper, the mass transport phenomena of EO processes, driven by concentration gradients, are reviewed. It is followed by reviewing the key factors that affect the separation performance of membrane particularly thin film composite (TFC) membrane during EO operation. Some of the factors reviewed include membrane intrinsic characteristics, filtration orientation, composition of the feed and draw solutions. This mini review is of importance for researchers who would like to start the research work in the field of osmotic membrane developments.

Research paper thumbnail of Ultrafiltration Membranes Incorporated with Carbon-Based Nanomaterials for Antifouling Improvement and Heavy Metal Removal

Carbon-Based Polymer Nanocomposites for Environmental and Energy Applications

Research paper thumbnail of Incorporation of modified cellulose nanocrystals to polyamide nanofiltration membrane for efficient removal of Cr(III) and Pb(II) ions from aqueous solutions

International Journal of Environmental Analytical Chemistry

In this study, thin-film nanocomposite nanofiltration (TFN) membranes were fabricated using inter... more In this study, thin-film nanocomposite nanofiltration (TFN) membranes were fabricated using interfacial polymerisation by incorporating modified cellulose nanoparticles (mNCs). In the first place, ...

Research paper thumbnail of Efficiency evaluation of titanium oxide nanocomposite membrane in adsorption of chromium from oil effluents

Environmental Monitoring and Assessment

Research paper thumbnail of Synthesis of Novel Hybrid NF/FO Nanocomposite Membrane by Incorporating Black TiO2 Nanoparticles for Highly Efficient Heavy Metals Removal

International Journal of Environmental Research, 2021

In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the ai... more In this study, a hybrid of nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving the efficiency of heavy metal removal. Here, black TiO2 nanoparticles (BNPs) were synthesized first and embedded in the polyamide (PA) active layer of TFC NF membrane to rectify the performance of membranes. The resulting TFN NF membranes were then tested in hybrid NF/FO system properly. The presence of BNPs was confirmed with XPS and FTIR, while the morphological alterations in the synthetized membranes were characterized using FESEM and AFM. Nanofiltration membrane performance was examined using multivalent ions such as of MgSO4, Na2SO4, CaCl2, and NaCl monovalent ion. We demonstrated that the addition of BNPs led to a significant decrease in surface roughness and hydrophilicity, showing a further reduction with increased concentrations of BNPs. In addition, TFC membrane showed a water flux of 25 L/m2h compared to 39, 41, and 66 L/m2h for TFN0.01, TFN0.05, and TFN0.1 membranes, respectively. We also showed that under the FO process, TFN membrane demonstrated the best performance with regards to heavy metal rejection and the highest Cr (III) and Pb (II) rejection was shown in TFN0.05 under the FO process. The ideal heavy metal rejections and acceptable water flux indicate the potential of these developed membranes under FO process for the removal of heavy metals from wastewater. In this study, a hybrid of Nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving heavy metals removal efficiency. In this situation where black TiO2 nanoparticles (BNPs), in fact, were synthesized firstly and then embedded in the polyamide (PA) active layer of TFC NF membrane to rectified membrane performances. Polysulfone (PSF) Udel P-3500 in pellet form (Solvay Advanced Polymers), dimethylacetamide (DMAC, N99.5%, Merck) as solvent and polyvinylpyrrolidone (PVP K30, Sigma-Aldrich) and 1- methyl-2-pyrrolidinone (NMP, Sigma-Aldrich) as additive were employed for membrane substrate synthesis. Substrate membrane was synthetized with dope solution that was made up of 17.5% PSF, 0.5% PVP and 82% DMAC. The top active layer of TFN membrane was formed by interfacial polymerization on the surface of a pre-cast PSF substrate. In the present work, cyclohexane was used as the organic solvent for better dispersion of BNPs. BNPs were added into cyclohexane containing TMC monomer. The mixture was then sonicated for 3 h to avoid the nanoparticle agglomeration. We also determined the zeta potential of TFC and TFN. membrane fabricated with BNP demonstrated a more negative zeta potential value compared to the pristine TFC membrane due to the increased number of oxygen-containing functional groups on the membrane surface. In this study, a hybrid of Nanofiltration (NF) and forward osmosis (FO) has been used with the aim of improving heavy metals removal efficiency. In this situation where black TiO2 nanoparticles (BNPs), in fact, were synthesized firstly and then embedded in the polyamide (PA) active layer of TFC NF membrane to rectified membrane performances. Polysulfone (PSF) Udel P-3500 in pellet form (Solvay Advanced Polymers), dimethylacetamide (DMAC, N99.5%, Merck) as solvent and polyvinylpyrrolidone (PVP K30, Sigma-Aldrich) and 1- methyl-2-pyrrolidinone (NMP, Sigma-Aldrich) as additive were employed for membrane substrate synthesis. Substrate membrane was synthetized with dope solution that was made up of 17.5% PSF, 0.5% PVP and 82% DMAC. The top active layer of TFN membrane was formed by interfacial polymerization on the surface of a pre-cast PSF substrate. In the present work, cyclohexane was used as the organic solvent for better dispersion of BNPs. BNPs were added into cyclohexane containing TMC monomer. The mixture was then sonicated for 3 h to avoid the nanoparticle agglomeration. We also determined the zeta potential of TFC and TFN. membrane fabricated with BNP demonstrated a more negative zeta potential value compared to the pristine TFC membrane due to the increased number of oxygen-containing functional groups on the membrane surface.

Research paper thumbnail of Integration of Porous Nanomaterial-Infused Membrane in UF/FO Membrane Hybrid for Simulated Osmosis Membrane Bioreactor (OsMBR) Process

Membranes

This study explored the use of a combination of hydrothermal and sol–gel methods to produce porou... more This study explored the use of a combination of hydrothermal and sol–gel methods to produce porous titanium dioxide (PTi) powder with a high specific surface area of 112.84 m2/g. The PTi powder was utilized as a filler in the fabrication of ultrafiltration nanocomposite membranes using polysulfone (PSf) as the polymer. The synthesized nanoparticles and membranes were analyzed using various techniques, including BET, TEM, XRD, AFM, FESEM, FTIR, and contact angle measurements. The membrane’s performance and antifouling properties were also assessed using bovine serum albumin (BSA) as a simulated wastewater feed solution. Furthermore, the ultrafiltration membranes were tested in the forward osmosis (FO) system using a 0.6-weight-percent solution of poly (sodium 4-styrene sulfonate) as the osmosis solution to evaluate the osmosis membrane bioreactor (OsMBR) process. The results revealed that the incorporation of PTi nanoparticles into the polymer matrix enhanced the hydrophilicity and s...

Research paper thumbnail of Fabrication and evaluation of nanofiltration membrane coated with amino-functionalized graphene oxide for highly efficient heavy metal removal

International Journal of Environmental Science and Technology, 2021

In this study, two different methods were used to introduce functionalized graphene oxide (GO) on... more In this study, two different methods were used to introduce functionalized graphene oxide (GO) onto the surface of nanofiltration (NF) membrane to improve its performance for heavy metal removal. The first method was based on coating in which the surface of NF membrane was coated with cross-linked GO, while the second method was introducing GO into monomer solution during interfacial polymerization. The efficiency of different methods was then compared by characterizing membrane physiochemical properties, as well as separation performance. With regard to performances, the water flux of TFN-i2 membrane (with GOs incorporated into thin layer) was reported to be 95 L/m2 h compared to 75 L/m2 h found in the TFN-c2 membrane (with GOs coated on the surface) at 8 bar. Both modified membranes exhibited higher water flux than the control membrane without GO incorporation (40 L/m2 h). Although the water flux of TFN-c2 membrane was lower, it achieved higher cobalt removal (97%) than that of TFN-i2 membrane (73%) due to its higher negative surface charge that improved separation via the Donnan exclusion effect.

Research paper thumbnail of Synthesis, modification and optimization of titanate nanotubes-polyamide thin film nanocomposite (TFN) membrane for forward osmosis (FO) application

Chemical Engineering Journal, 2015

h i g h l i g h t s Self-synthesized amino-functionalized TNTs with unique characteristics for TF... more h i g h l i g h t s Self-synthesized amino-functionalized TNTs with unique characteristics for TFN FO membrane. Synthesis of novel TFN FO membrane with greater water flux and lower reverse draw solute. Covalent bonding between nanotubes and PA layer improved separation properties of TFN membrane.

Research paper thumbnail of Effect of air-gap length on carbon dioxide stripping performance of a surface modified polysulfone hollow fiber membrane contactor

RSC Adv., 2014

Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps t... more Surface Modifying Macromolecule (SMM) blended PSf hollow fibers were spun at different air-gaps to evaluate CO 2 stripping from aqueous DEA solution and water. The fabricated membranes were firstly subjected to different characterization methods such as contact angle and liquid entry pressure measurement to evaluate the membrane's hydrophobicity and wetting resistance, respectively. To determine pore size and effective porosity of the membranes, a pure helium permeation test was performed. Morphological study of the membranes was conducted by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A CO 2 stripping test was carried out to investigate the effects of operating variables such as liquid and gas velocity, temperature and DEA concentration on the CO 2 stripping flux. It was found that the increase of liquid velocity resulted in enhanced CO 2 stripping flux. On the other hand, the increase in gas velocity did not exert significant influence on the stripping flux. The increase in temperature and DEA concentration both enhanced the stripping flux. Lastly, it was concluded that the hollow fibers spun in this work at a 15 cm air-gap could achieve the best stripping flux among all the membranes fabricated so far for CO 2 stripping.

Research paper thumbnail of Carbon dioxide stripping from water through porous polysulfone hollow fiber membrane contactor

Separation and Purification Technology, 2013

Carbon dioxide (CO 2) stripping from water was conducted through the porous asymmetric polysulfon... more Carbon dioxide (CO 2) stripping from water was conducted through the porous asymmetric polysulfone (PSf) hollow fiber membrane contactor. The effect of the liquid and gas flow rates on the stripping performance, the liquid phase CO 2 concentration and the CO 2 stripping efficiency of the membrane module and the effect of liquid phase temperature on CO 2 stripping flux were studied. The experimental results showed that the stripping gas velocity had a minor effect on the CO 2 desorption flux while the increase in the liquid velocity could enhance CO 2 desorption flux in the gas stripping membrane contactor. By increasing liquid flow rate to 200 ml/min, the maximum CO 2 stripping efficiency of almost 66% was achieved. Enhancement of liquid flow rate from 50 to 200 ml/min increased the CO 2 flux around 482%. It was found that the CO 2 stripping flux was significantly affected by the liquid phase temperature. By increasing liquid temperature from 80 to 90°C, the CO 2 stripping flux increased from 1.3 Â 10 À4 to 4.9 Â 10 À4 mol m À2 s À1 at liquid velocity of 200 ml min À1. Hence, the higher stripping efficiency can be achieved by applying the higher liquid flow rate in the membrane contactor module. As well, the liquid phase temperature is a key parameter that needs to be controlled.

Research paper thumbnail of A novel thin film nanocomposite reverse osmosis membrane with superior anti-organic fouling affinity for water desalination

Desalination, 2015

ABSTRACT In this work, titanate nanotubes (TNTs) were self-synthesized and amino functionalized t... more ABSTRACT In this work, titanate nanotubes (TNTs) were self-synthesized and amino functionalized to produce titanate nanotubes (NH2-TNTs) for thin film nanocomposite (TFN) reverse osmosis (RO) membrane fabrication. The novel RO membranes were fabricated by embedding NH2-TNTs of different quantities into polyamide (PA) layer. The nanotubular morphology of NH2-TNTs was studied using TEM while FTIR was employed to confirm the reaction of TNTs with [1-(2-amino-ethyl)-3-aminopropyl] trimethoxysilane. The effect of NH2-TNTs on the PA layer of TFNwith respect to surfacemorphology, separation performance and antifouling properties was thoroughly investigated and discussed. The presence of NH2-TNTs in PA layer was verified using XPS while the “leaflike” outgrowth morphology of PA layer was observed using FESEM. Results showed that the TFN membrane with 0.05% NH2-TNTs embedded was the most promising membrane as it exhibited 93% higher water flux than the control thin film composite (TFC) membrane, without compensating NaCl rejection. In terms of organic fouling tendency, the TFN0.05 membrane also showed higher tolerance compared to the controlmembrane during RO process. Furthermore, as high as 94% of the water flux of TFN0.05 was able to retrieve by a simple water rinse process, which suggests that organic fouling in TFN0.05 is highly reversible.

Research paper thumbnail of SPEEK/cSMM membrane for simultaneous electricity generation and wastewater treatment in microbial fuel cell

Journal of Chemical Technology & Biotechnology, 2015

Research paper thumbnail of Power generation and wastewater treatment using a novel SPEEK nanocomposite membrane in a dual chamber microbial fuel cell

International Journal of Hydrogen Energy, 2015

In this paper, the performance of two common and two self-fabricated proton exchange membranes we... more In this paper, the performance of two common and two self-fabricated proton exchange membranes were compared. Nafion 112 and Nafion 117, which are two of the most common proton exchange membranes that can be used in all fuel cell systems, were compared to SPEEK and SP/CC/TAP. The results showed that at lower COD such as 2000 mg/l, Nafion 117 has the highest performance in terms of power production and COD removal, while once the COD of wastewater goes up to 5000 mg/l, SP/CC/TAP has approximately the same performance as Nafion 117. The membranes were characterized by FESEM, while the degree of sulfonation was measured by NMR. The oxidation activity of microorganisms was measure by cyclic voltammetry (CV). Also, the attachment of bacteria onto the anode electrode was observed by SEM, which showed that different bacteria from the media with a mixed culture inoculum had attached to the anode electrode.

Research paper thumbnail of Effect of SMM concentration on morphology and performance of surface modified PVDF hollow fiber membrane contactor for CO2 absorption

Separation and Purification Technology, 2013

Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a dry-... more Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes were fabricated via a dry-wet phased inversion process. Surface modifying macromolecules (SMMs) (0, 2, 4 and 6 wt.%) were used as additives in the spinning dope. During phase inversion SMM migrates to the membrane surface, resulting in different surface morphology and surface chemistry. The surface modified PVDF membranes showed the larger pore size, higher gas permeance, effective surface porosity, contact angle and overall porosity but lower critical water entry pressure compared to the PVDF hollow fiber membrane without SMM. The performance of the surface modified membrane in contactor application for physical CO 2 absorption was investigated by the fabricated gas-liquid membrane contactor module, where distilled water was used to dissolve CO 2. It was found that the liquid phase resistance was dominant in the absorption experiment. The results show that the surface modified PVDF membrane has a higher performance compared to control PVDF membrane. By increasing SMM concentration in the spinning dope, the CO 2 absorption flux increased significantly. With the membrane prepared from 6 wt.% of SMM in the spinning dope, a maximum CO 2 absorption flux of 5.4 Â 10 À3 mol/m 2 s was achieved at 300 ml min À1 of absorbent flow rate, which was almost 650% more than the fabricated membrane without SMM.

Research paper thumbnail of Synthesis and characterization of thin film nanocomposite forward osmosis membrane with hydrophilic nanocomposite support to reduce internal concentration polarization

Journal of Membrane Science, 2014

Realizing that one of the most important challenges in the forward osmosis (FO) membrane is inter... more Realizing that one of the most important challenges in the forward osmosis (FO) membrane is internal concentration polarization (ICP), thin film nanocomposite (TFN) membranes were prepared by incorporating different loadings of titanium dioxide (TiO 2) nanoparticles (ranging from zero to 0.90 wt%) into the polysulfone (PSf) substrate in order to reduce ICP. The nanocomposite substrates prepared were characterized with respect to hydrophilicity, overall porosity, surface roughness and cross-sectional morphology by different methods. Results revealed that both hydrophilicity and porosity of the substrate were increased upon addition of TiO 2 nanoparticles. Moreover, a large number of finger-liked macrovoids were developed by increasing the loading of TiO 2 nanoparticles, leading to enhancement in water permeability. As for the FO performance tested at AL-FS orientation and with DI water as feed and 0.5 M NaCl as draw solution, the TFN membrane prepared using PSf substrate embedded with 0.60 wt% TiO 2 nanoparticles (designated as TFN0.60) exhibited the most promising result by showing water flux of 18.81 L/m 2 .h, i.e. 97% higher than the control TFC membrane prepared by substrate without TiO 2 incorporation (designated as TFC), with no significant change in reverse solute flux. Compared to the control TFC membrane, the FO water flux of TFN0.60 was also reported to increase significantly from 4.2 to 8.1 L/m 2 .h (AL-FS orientation) and 6.9 to 13.8 L/m 2 .h (AL-DS orientation) when seawater was used as feed solution and 2 M NaCl was used as draw solution. The increase in water flux can be attributed to the decrease in structural parameter (S value = 0.39 mm), mainly due to the formation of finger-liked macrovoids that connect the top and bottom layer of the substrate and reduce the tortuosity, resulting in decreased ICP. Although further increasing TiO 2 nanoparticles loading to 0.90 wt% could increase membrane water permeability, the FO performance was compromised by a significant increase in reverse solute flux. To the best knowledge of the authors, this is the first report on TFN membrane using PSf-TiO 2 nanocomposite substrate for FO applications.

Research paper thumbnail of Synthesis of thin film nanocomposite forward osmosis membrane with enhancement in water flux without sacrificing salt rejection

Desalination, 2013

ABSTRACT In this study, thin film nanocomposite (TFN) membrane was developed using novel polysulf... more ABSTRACT In this study, thin film nanocomposite (TFN) membrane was developed using novel polysulfone–titanium dioxide (PSf–TiO2) nanocomposite substrate. The effects of TiO2 on the PSf substrate morphologies, hydrophilicity and water permeability were investigated and discussed. The results revealed that the hydrophilicity and the porosity of the substrate were improved upon the TiO2 addition, leading to significant enhancement in water flux. TFN membrane was then fabricated by establishing a polyamide layer made of 1,3-phenylendiamine and 1,3,5-benzenetricarbonyl trichloride monomers over the surface of the modified substrate. Compared with the typical TFC and commercial CTA membranes, the TFN membrane prepared always demonstrated much higher FO water flux without showing a significant increase in reverse solute flux when tested under same conditions. When tested in AL–FS orientation using 0.5 M NaCl as a draw solution and 10 mM NaCl as feed solution, the water flux of the TFN membrane was ∼ 120% and ∼ 87% higher than that of the commercial membrane and typical TFC membrane, respectively. The water flux of the TFN membrane was also reported to be much higher under prolonged filtration time, mainly due to the improved properties of substrate upon addition of TiO2.

Research paper thumbnail of A novel thin film composite forward osmosis membrane prepared from PSf–TiO2 nanocomposite substrate for water desalination

Chemical Engineering Journal, 2014

ABSTRACT In this work, polysulfone (PSf)–titanium dioxide (TiO2) nanocomposite substrates were pr... more ABSTRACT In this work, polysulfone (PSf)–titanium dioxide (TiO2) nanocomposite substrates were prepared by incorporating different amounts of TiO2 nanoparticles (ranging from zero to 1 wt%) into PSf matrix. The nanocomposite substrates so prepared were then characterized with respect to hydrophilicity, overall porosity, surface roughness and cross-sectional morphology. It was found that both hydrophilicity and porosity of the substrate were increased upon addition of TiO2. In addition, long finger-like structures were developed by increasing the TiO2 loading, leading to water permeability enhancement. In order to fabricate thin film nanocomposite (TFN) membranes for forward osmosis (FO) application, a thin polyamide layer was formed by interfacial polymerization of 1,3-phenylendiamine and 1,3,5-benzenetricarbonyl trichloride on the top surface of PSf–TiO2 nanocomposite substrates. Under the conditions for FO performance evaluation (10 mM NaCl concentration in feed solution, 0.5 and 2.0 M NaCl concentration in draw solution, and both active layer facing the feed solution (AL–FS) and active layer facing the draw solution (AL–DS) orientations), the TFN membrane prepared using PSf substrate embedded with 0.5 wt% TiO2 nanoparticles (denoted as TFN0.5) exhibited the most promising results by showing high water permeability and low reverse solute flux. In comparison with control TFC membrane, the water flux of TFN0.5 membrane was improved by 86–93%, depending on the membrane orientation and draw solution concentration. The increase in water permeability can be attributed to decrease in structural parameter which resulted in decreased internal concentration polarization (ICP). Although further increase in TiO2 nanoparticles loading to 0.75 and 1 wt% could result in higher water permeability, their FO performances were compromised by a significant increase in reverse solute flux. Based on the results obtained in this work, it can be concluded that adding an appropriate amount of TiO2 nanoparticles into PSf substrate could potentially improve the performance of TFC membrane during FO applications.

Research paper thumbnail of Study on CO2 stripping from water through novel surface modified PVDF hollow fiber membrane contactor

Chemical Engineering Journal, 2014

ABSTRACT Graphical abstract Schematic of CO2 stripping mechanism through gas–liquid membrane cont... more ABSTRACT Graphical abstract Schematic of CO2 stripping mechanism through gas–liquid membrane contactor.

Research paper thumbnail of Influence of air-gap length on CO2 stripping from diethanolamine solution and water performance of surface modified PVDF hollow fiber membrane contactor

Iranian Journal of Chemistry & Chemical Engineering-international English Edition, 2018

Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air... more Surface Modifying Macromolecule (SMM) blended PVDF hollow fibers (HFs) were spun at different air-gaps (o to 20 cm) and used for CO2 stripping from aqueous DEA solution and water. The manufactured fibers were firstly subjected to various characterization tests such as contact angle and critical water entry pressure measurement to evaluate the HF hydrophobicity and wetting resistance, respectively. The pure helium permeation experiments were also conducted to obtain membrane pore size and effective porosity. Morphology of the HFs was investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The SEM images showed that both outer and inner diameters of HFs decreased significantly by increasing air-gap length which mainly because of elongation of HF caused by gravity while travelling through the air-gap. Also, the gradual decrease in roughness on the external surface of the produced HFs was observed from the AFM images. It was found that the increase of liqui...

Research paper thumbnail of Mini Review on the Effects of Concentration Polarization in Forward Osmosis and Pressure-retarded Osmosis Processes

Extended Abstract Discharge of water from the boundary layer of the thin film composite membrane ... more Extended Abstract Discharge of water from the boundary layer of the thin film composite membrane can unbalance the concentration of solution at the membrane–feed interface and the bulk solution. This phenomenon is known as concentration polarization, and is common in pressure-driven membrane processes, particularly in reverse osmosis (RO) and nanofiltration (NF), but also in emerging forward osmosis (FO) and pressure retarded osmosis (PRO) processes. There are two types of concentration polarization, external (ECP) and internal (ICP). The effect of concentration polarization is always to decrease the membrane productivity (water flux) and selectivity (salt rejection); in other words, it undermines membrane performance regardless of the process. The ECP can occur at both interfaces of a membrane and can be dilutive or concentrative. However, it can be mitigated by promoting turbulence at a fluid-membrane interface. On the other hand, the ICP, which also can be dilutive or concentrati...

Research paper thumbnail of A Review on Mass Transport Phenomena and Factors Affecting the Performance of Thin Film Composite Membrane during Engineered Osmosis Process

Engineered osmosis (EO) is an osmotically driven membrane process that takes advantage of the osm... more Engineered osmosis (EO) is an osmotically driven membrane process that takes advantage of the osmotic pressure gradient to drive water across the semi-permeable membrane from the feed solution (low osmotic pressure) to the draw solution (high osmotic pressure). In the last decade, EO membranes have found various applications in wastewater treatment, seawater/brackish desalination, food processing and power generation. In this paper, the mass transport phenomena of EO processes, driven by concentration gradients, are reviewed. It is followed by reviewing the key factors that affect the separation performance of membrane particularly thin film composite (TFC) membrane during EO operation. Some of the factors reviewed include membrane intrinsic characteristics, filtration orientation, composition of the feed and draw solutions. This mini review is of importance for researchers who would like to start the research work in the field of osmotic membrane developments.

Research paper thumbnail of Ultrafiltration Membranes Incorporated with Carbon-Based Nanomaterials for Antifouling Improvement and Heavy Metal Removal

Carbon-Based Polymer Nanocomposites for Environmental and Energy Applications

Research paper thumbnail of Incorporation of modified cellulose nanocrystals to polyamide nanofiltration membrane for efficient removal of Cr(III) and Pb(II) ions from aqueous solutions

International Journal of Environmental Analytical Chemistry

In this study, thin-film nanocomposite nanofiltration (TFN) membranes were fabricated using inter... more In this study, thin-film nanocomposite nanofiltration (TFN) membranes were fabricated using interfacial polymerisation by incorporating modified cellulose nanoparticles (mNCs). In the first place, ...