
Takuji ShintaniKobe University | Shindai
Takuji Shintani
Doctor of Engineering
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95
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Publications (95)
Thiophene–thiophene block copolymer composed of hydrophilic and hydrophobic side chain functionalities was designed and synthesized. Deprotonative metalation nickel-catalyzed polymerization protocol successfully afforded the block copolymer, which side chains are derived...
Membrane fouling is inevitable during the membrane separation process. The difference in the driving force of reverse osmosis (RO) and forward osmosis (FO) affects the behavior of foulants. Thus, in this work, we examined the behavior of different foulants during the FO or RO process, including before and after physical cleaning of the membrane. Th...
For the first time, self-standing microfiltration (MF) hollow fiber membranes were prepared from cellulose triacetate (CTA) via the thermally induced phase separation (TIPS) method. The resultant membranes were compared with counterparts prepared from cellulose diacetate (CDA) and cellulose acetate propionate (CAP). Extensive solvent screening by c...
Solvent resistance of graphene oxide (GO) makes it a promising material to construct membranes for precise separations with solvent-involved conditions. A thin GO laminate layer supported by a porous substrate displaying a thin film composite (TFC) membrane configuration is commonly employed, and integration of the composite structure is necessary...
A superwetting forward osmosis membrane was prepared by grafting a zwitterion (2‐methacryloyloxyethyl phosphorylcholine, MPC) onto the polyamide membrane layer via atom transfer radical polymerization (ATRP) to enhance antifouling property. The modification of the hydrophilic layer was confirmed by the characterization including Fourier‐transform i...
TiO2-ZrO2-(3,5-di-tert-butylcatechol, DTBC) composite membranes were fabricated via the sol-gel method under four different firing conditions: 300 oC (N2), 300 oC (Air), 350 oC (Air), and 500 oC (Air). The chemical structure of the DTBC originated organic material in the composite was controlled by setting the firing temperature. The average pore s...
One process involved in biorefinery for generation of value‐added products is fermentation. After fermentation, the downstream bioproduct purification process is conventionally performed by organic solvent extraction, which is environmentally‐hazardous and costly. Membrane‐based separation is a cost‐efficient and environmentally‐benign method for b...
A photocatalytic membrane for water treatment is required to have an efficient photocatalytic functions and high membrane performances, therefore, it is necessary to design a functional membrane structure that achieves both requirements. Herein, we describe two-dimensional material engineering on heterostructured nanochannels comprising graphitic c...
Forward osmosis (FO) has attracted attention for wastewater treatment owing to its energy-saving characteristics; however, the low rejection of ammoniacal nitrogen (NH4⁺-N) for normal polyamide thin-film composite (TFC) FO membranes limits their practical applications for NH4⁺-N recovery or concentration from wastewater. Herein, ethylenediamine (ED...
Osmotically assisted reverse osmosis (OARO) has been recently proposed for concentrating high-salinity brines. The long-term performance stability of the membrane is essential for OARO, considering the long-term commercial operation. In this study, we developed hollow fiber membranes for OARO operation made of cellulose triacetate, and elucidated t...
Organic solvent reverse osmosis (OSRO) is currently considered as an energy-efficient membrane technology for separation of organic liquid mixtures. The conventional hydrophilic polyamide thin film (TFC) membrane was previously reported...
We report a new type of alkaline-stable hollow-fiber reverse osmosis (RO) membrane with an outside-in configuration that was established via adsorption of positively charged poly(vinyl alcohol) copolymers containing a small amount of quaternary ammonium moieties. Anionic sulfonated poly(arylene ether sulfone nitrile) hollow-fiber membranes were uti...
Isopropyl alcohol (IPA) is frequently used for cleaning fine patterns of semiconductor devices and technology to remove the fine particles from IPA is desired in the industry. In this study, an anion exchange membrane was used to remove silica nanoparticles, and zeta potential measurements were conducted on the particles and the membrane in an IPA/...
Reverse osmosis (RO) is a widely used energy-efficient separation technology for water treatment. Polyamide (PA) membranes are the conventional choice for this process. Fouling is a serious problem for RO separation. This issue leads to significant decreases in the water permeability of PA membranes, and it has yet to be fully elucidated. In partic...
Organic solvent nanofiltration (OSN) is an energy-efficient alternative to distillation and evaporation for the separation of mixtures containing organic liquids. Laminar membranes using nanosheets as building blocks have great potential for OSN; however, a swelling of the interlayer spacing causes a severe decrease in the separation performance. H...
The use of an Amphotericin B_Ergosterol (AmBEr) channel as an artificial water channel in forward osmosis filtration (FO) was studied via molecular dynamics (MD) simulation. Three channel models were constructed: a common AmBEr channel and two modified C3deOAmB_Ergosterol (C3deOAmBEr) channels with different diameters (12 Å and 18 Å). During FO fil...
A new method for the preparation of chemically robust thin-film composite hollow-fiber (TFC-HF) nanofiltration membranes through a dip-coating process is reported. A negatively charged disulfonated poly(arylene ether sulfone) random copolymer (SPN-20) containing highly polar benzonitrile groups was utilized as a separation layer in a TFC-HF membran...
Observing the nanoporous structure inside membranes has been one of the greatest challenges in membrane research, and many recent studies have employed positron annihilation lifetime spectroscopy, among other methods, to gain structural insights. In this report, we demonstrate the significant potential of Raman spectroscopy for investigating the na...
Two-dimensional (2D) laminar membranes are attracting much attention in organic solvent nanofiltration owing to the promising permeation and selective performance derived from their 2D ultrathin separation layer. However, owing to easy swelling (enlargement of interlayer spacing), controlling the interlayer spacing in organic solvents and stable so...
Two-dimensional (2D) nanomaterials (nanosheets) are promising building blocks of functional membranes for molecular separation. The design of 2D nanochannels with a locally tuned interfacial layer is a key strategy for improving the separation performance. Here, we present a 2D laminar membrane with an interfacial dense heterolayer comprising HNb3O...
Organic liquid separation is frequently encountered in chemically relevant industries. Herein, an organic solvent reverse osmosis (OSRO) membrane fabricated by spin coating a Teflon polymer, AF2400, onto a solvent-resistant polyketone support is proposed for organic liquid separation. Nonpolar AF2400 promotes the permeation of nonpolar liquids whil...
This study demonstrates the feasibility of a novel preparation method for positively charged nanofiltration membranes. First, the interfacial polymerization of piperazine with trimesoyl chloride was conducted to form a base polyamide layer on a polyethylene microfiltration membrane, followed by plasma graft polymerization of [2-(methacryloyloxy)eth...
The development of highly selective organic solvent reverse osmosis (OSRO) membrane for organic liquid separation is in great demand, but remains very challenging owing to the small sizes of organic liquids. We recently reported a polyketone (PK) supported polyamide (PA) membrane as an OSRO membrane, but only with a moderate separation factor of 8....
Methyl gallate (MG) and ethyl ferulate (EF) with a benzene ring were separately used as aromatic organic chelating ligands (aOCLs) to prepare two versions of TiO2-ZrO2-aOCL composite sols via hydrolysis and polycondensation reactions with titanium(IV) isopropoxide (Ti(OC3H7)4) and zirconium(IV) butoxide (Zr(OC4H9)4). Thermogravimetric and FT-IR ana...
Poly(vinylidene difluoride) (PVDF) is the main stream material for water treatment membrane. Thermally induced phase separation (TIPS) is frequently used as a manufacturing technology to produce a porous membrane. In phase separation technology, polymeric additives can be added to control the pore structure of the porous membranes. In this study, i...
A polyamide (PA) thin-film nanocomposite (TFN) membrane embedded with post-synthetically functionalized metal-organic framework (MOF) nanofillers of imidazole-2-carbaldehyde (ICA) decorated UiO-66-NH2 nanofillers (ICA_d_UiO-66-NH2) was developed using the interfacial polymerization method. The ICA_d_UiO-66-NH2 nanofiller couples a surface water-cap...
Removing N-nitrosodimethylamine (NDMA), a regulated carcinogenic chemical, with a reverse osmosis (RO) membrane is a key challenge for enhancing the safety of reused potable water. This study aimed to achieve high rejection of NDMA and salts by plugging the nanopores in an RO membrane with linear-chain amines, amides, and epoxides. Plugging with am...
Reverse osmosis (RO) is commonly used to concentrate solutions in food preparation and environmental applications among others. Limitations on the applied pressure, which must be higher than the osmotic pressure of the feed solution, determine the concentration that can be achieved by RO. Recently, an osmotically assisted reverse osmosis (OARO) sys...
Separation of organic solvent by membrane is an emerging technology for the purification or separation of organic solvents. In this study, game changing OHF (Organic solvent Hyper Filtration) membranes and their applications are under development to realize the replacement from energy–consuming distillation to energy–efficient membrane process. Nan...
Poly(vinylidene difluoride) (PVDF) hollow fiber membranes were prepared by using high-temperature rapid non-solvent-induced phase separation (HTR-NIPS). The conditions for fabricating interconnected bicontinuous structures via HTR-NIPS were investigated. We found that (1) the stock solution must not have a gelation temperature and (2) the membrane...
In this study, we fabricated porous polyketone (PK) support membranes with high pressure resistance and low structural parameter (S) by surface modification with aromatic compounds for osmotically driven membrane process applications. The effects of surface modification of PK using aromatic compounds on the membrane structure, mechanical properties...
An amphiphilic copolymer was used in the fabrication of hydrophilized poly (vinylidene fluoride) (PVDF) membranes. The amphiphilic copolymer was synthesized via the catalytic chain transfer radical polymerization (CCTP) of poly (methyl methacrylate) macromonomer (PMMA-MM), 2-hydroxyethyl methacrylate (HEMA), and 2-methoxyethyl acrylate (MEA). The c...
For the purpose of efficient separation of sulfate ions from magnesium ions, novel negatively-charged nanofiltration membranes were developed by incorporating the monoamines 4-aminobenozic acid, aniline-2,5-disulfonic acid monosodium salt, and iminodiacetic acid (IDA) during interfacial polymerization of piperazine (PIP) and trimesoyl chloride. PIP...
Advanced wastewater treatment using a reverse osmosis (RO) membrane is a key separation process for ensuring the removal of chemical hazards so that treated wastewater can be used for potable purposes. This study systematically assesses the effects of heat modification conditions of three commercial RO membranes on the removal of a challenging chem...
Energy-efficient membrane technology has received tremendous attention for the separation of organic molecules, however, the separation of molecules of less than 100 Da has remained challenging. Herein, a membrane fabricated from interfacial polymerization on a polyketone support was performed as an organic solvent reverse osmosis (OSRO) membrane f...
We developed a new hydrophilization method that we refer to as polyvinylalchohol (PVA) diffusion. This new method modifies the entire surface area of a hollow fiber membrane by diffusing PVA from the bore fluid to the outer surface. This method was used to prepare a hydrophilized polyvinylidene difluoride (PVDF) hollow fiber membranes (PVA-PVDF). A...
Membranes assembled by two-dimensional (2D) nanosheets have high potential for advanced molecular separation. The intercalation of nanomaterials into the laminar membrane is a promising strategy to control the nanochannel structure. We present 2D niobate nanosheet (NbN)-Graphene oxide (GO) composite membranes fabricated by simple vacuum filtration....
Organic chelate ligand (OCL)-templated TiO2–ZrO2 nanofiltration membranes were fabricated. Three types of OLCs, isoeugenol (ISOH), 2,3-dihydroxynaphthalene (DHN), and ethyl acetoacetate (EAA) were examined for use in the preparation of a TiO2–ZrO2 thin separation layer. All employed OCLs were completely decomposed and removed with firing at 500 °C...
Molecular simulation was adopted to investigate and compare the water-channel performance of a common Amphotericin B_Ergosterol (AmBEr) model with that of two hydrophobically modified Amphotericin B_Ergosterol (C3deOAmBEr) models. Structural characteristics and transport performances were also examined. The energy levels of the simulation models we...
Niobate nanosheet membranes were fabricated by vacuum filtration using niobate nanosheets prepared by the hydrothermal method (HT-NbO membranes) and the exfoliation method (EX-NbO membranes). Membrane structure, water permeance and separation performance for these membrane types were measured and compared. Both membrane types had a dense structure...
Reliable and adequate removal of small and uncharged trace organic chemicals (TOrCs), particularly N-nitrosodimethylamine (NDMA) that is carcinogenic and known to occur in treated effluent, is essential for implementing direct potable water use. This study provides new insights to explain the low rejection of NDMA and other N-nitrosamines by revers...
Two-dimensional (2D) nanosheets show promise for the development of water treatment membranes with extraordinary separation properties and the advantages of atomic thickness with micrometer-sized lateral dimensions. Stacked graphene oxide (GO)-based membranes can demonstrate unique molecular sieving properties with fast water permeation. However, i...
Polyamide (PA) membranes possess properties that allow for selective water permeation and salt rejection, and these are widely used for reverse osmotic (RO) desalination of sea water to produce drinking water. In order to design high-performance RO membranes with high levels of water permeability and salt rejection, an understanding of microscopic...
Membranes used for pressure-retarded osmosis (PRO) are required to be mechanically strong due to high external hydraulic pressures on the draw solution (DS) side. In this study, a series of non-woven fabrics of varying thickness, density, and hydrophilicity were used to fabricate reinforced aliphatic polyketone (PK) membranes with excellent mechani...
The hydrothermal pretreatment of rice straw generates a liquid fraction that contains low concentrations of sugars, as well as fermentation inhibitors which are not favourable for efficient bioethanol production. For the development of a forward osmosis (FO) process to concentrate sugars and remove fermentation inhibitors, we fabricated polyamide-p...
We developed new polyamide 6 hollow fibre membranes using a green process to fabricate cutting-edge “organic solvent nanofiltration” membranes by one-step spinning process for organic solvent separation.
The polyamide skin layer of reverse osmosis (RO) membranes was characterised using advanced and complementary analytical techniques to investigate the mechanisms underlying the permeation of contaminants of emerging concern in potable water reuse – N-nitrosodimethylamine (NDMA) and N-nitrosomethylethylamine (NMEA). This study used five RO membrane...
In this study, the transport performance of water molecules and the ion-rejection ability of cyclic peptide nanotubes (CPNTs) were examined on a molecular level via a simulation of forward osmosis (FO) filtration phenomena. A FO filtration model and three types of CPNTs, 8CP, Mba-8CP, and 4Mba-8CP (with different levels of modification by hydrophob...
Direct potable reuse is becoming a feasible option to cope with water shortages. It requires more stringent water quality assurance than indirect potable reuse. Thus, the development of a high-rejection reverse osmosis (RO) membrane for the removal of one of the most challenging chemicals in potable reuse - N-nitrosodimethylamine (NDMA) - ensures f...
In this study, molecular simulation was used to explore the structural characteristics and water transport performance of Amphotericin B-Brgosterol (AmBEr) channels. A molecular dynamics (MD) technique was used to construct two types of molecular models of AmBEr channels: single-layer channel (SLC) and double-layer channel (DLC). A MD simulation wa...
Niobate nanosheets are assembled into thin membranes by a vacuum filtration. The nanosheet membranes have a dense and stable structure in water via chemical cross-linking and show higher permeance and salt rejection compared with graphene oxide membranes. A water pathway model based on the void structure is presented to explain the membrane perform...
In this study, water–molecule transport properties of an Amphotericin B–Ergosterol (AmBEr) channel were examined on a molecular level via simulation of the forward osmosis (FO) filtration phenomena. FO filtration and doublelayer channel (DLC) AmBEr channel models were constructed via molecular dynamics (MD). MD simulation was adopted to explain the...
Polyamide membranes with a controlled surface morphology were prepared by the interfacial polymerization of 1,3-phenylenediamine (MPD) with 1,3,5-benzenetricarbonyl trichloride (TMC) on polysulfone ultrafiltration supports. In a novel polymerization method, co-solvents, which included acetone, ethyl acetate, diethyl ether, toluene, isopropyl alcoho...
Polyamide membranes with controlled surface morphology were prepared by the interfacial polymerization of 1,3-phenylenediamine (MPD) with 1,3,5-benzenetricarbonyl trichloride (TMC) on polysulfone ultrafiltration supports. The addition of co-solvents (acetone, ethyl acetate, and diethyl ether) into the organic phase was used to control both the surf...
A battery separator (13) of the present invention includes a porous film (12) serving as a substrate and a crosslinked polymer layer (11) supported on the porous film (12). The crosslinked polymer layer (11) contains a crosslinked polymer and inorganic particles, and is non-porous. The crosslinked polymer is obtained by reacting a reactive polymer...
A spray-assisted, 2-step interfacial polymerization (IP) of trimesoyl chloride (TMC)/m-phenylenediamine (MPD) was proposed for the preparation of polyamide (PA) membranes. In the first step, TMC/hexane solutions were sprayed onto MPD-impregnated polysulfone (PSI) supports for 10-60 s, followed by a second step where the first-step membranes made co...
The positron annihilation technique using a slow positron beam can be
used for the study of the vacancy profiles in typical reverse osmosis
(RO) membranes. In this study, the vacancy profile in the polyamide
membrane that exhibits a high permselectivity between ions and water was
studied using the positron annihilation technique and molecular dynam...
A method of membrane separation and membrane separation apparatus, with which not only a supply liquid can be evaluated but also the problems, such as scale, occurring on reverse osmosis membrane can be monitored in a highly straightforward fashion. There is provided a membrane separation apparatus equipped with reverse osmosis membrane module (3)...
Poly-phthalazinone-ether-sulfone (PPES) polymer is a relatively newly developed material with a bis(4-fluorodiphenyl) sulfone group. The formation of the PPES membrane by wet-phase inversion can proceed according to a slow or fast gelation method. These formation mechanisms were studied experimentally. The resulting membrane morphology was investig...
A process for producing a microporous polymeric object to improve the degree of freedom for its various properties, compared to conventional processes, includes: mixing a block copolymer made of three or more kinds of segments with a polymer, wherein one or more of the segments are made of monomer units having a first functional group forming ionic...
This study introduces a promising strategy, called co-solvent assisted interfacial polymerization (CAIP), for the synthesis of thin polyamide membranes by interfacial polymerization of 1,3-phenylenediamine (MPD) with 1,3,5-benzenetricarbonyl trichloride (TMC) on polysulfone ultrafiltration supports. A synergistic co-solvent added in the hexane phas...
The pore radius of a reverse osmosis membrane was evaluated by considering the molecular shape of uncharged organic solutes. Molecular shape was approximated by a rectangular parallelepiped; molecular length (L) and molecular width (MWd) were used as shape parameters. The steric partition factor of a solute was calculated from L and MWd, and the St...
A promising strategy is reported for the synthesis of inorganic-polyamide nanocomposite membranes on an ultrafiltration polysulfone support via metal-alkoxide-assisted interfacial polymerization. Three types of nanocomposite membranes were prepared using three different metal alkoxides. The metal alkoxides used here were titanium tetraisopropoxide,...
A new concept for the synthesis of thin polyamide nanofiltration membranes on ultrafiltration polysulfone supports is reported. Polyamide membranes with controllable thin dense layer and effective “nanopores” were fabricated by adding co-solvent (acetone) to nonpolar organic phase (hexane), referred to as co-solvent assisted interfacial polymerizat...
A new type of zeolite-incorporated thin polyamide nanocomposite membrane that exhibits high water flux with high solute rejection can be synthesized by “pre-seeding” modified zeolite particles on a polysulfone ultrafiltration support surface prior to interfacial polymerization.
We examined the effects of molecular shape on the rejection of uncharged organic compounds by nanofiltration membranes and on pore radii calculated for those membranes. Molecular shape was approximated by a rectangular parallelepiped; molecular length (L) and molecular width (MWd) were used as shape parameters. The steric partition factor of a solu...
Poly (phthalazinone ether sulfone ketone) (PPESK) copolymer is a relatively newly developed material, which contains different component ratios of diphenyl ketone and diphenyl sulfone with respect to a certain amount of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one. In this study, the physico-chemical characteristics of this copolymer, including the gla...
In our series of studies for the development of a reverse osmosis polyamide membrane with high resistance to chlorine, N,N′-dimethyl-m-phenylenediamine (N,N′-DMMPD) was selected in the preparation of the polyamide membrane after the screening of various diamines. High resistance to chlorine was confirmed for the prepared membrane in our previous wo...
Three kinds of polyamides were synthesized from three diamines and 1,3,5-benzenetricarbonyl trichloride (TMC). The diamines used were m-phenylene diamine, N-methyl-m-phenylenediamine, and N,N′-dimethyl-m-phenylenediamine. The average free volume sizes of the polyamides were measured by positron annihilation lifetime spectroscopy (PALS), and the fre...
The primary goal of this paper is to investigate the separation performance of bicarbonate salts through nanofiltration (NF) membrane LES 90. The experiment results indicate that the observed transmissions of total carbon (TC) at pH 7 are much higher than that at pH 8.3. This phenomenon can be explained by the dynamical equilibrium of weak electrol...
PROBLEM TO BE SOLVED: To provide a substrate for cell culture having an excellent efficiency for cell culture without requiring immobilization or adsorption of a cell-adhesive material on the surface of the base material. ;SOLUTION: Provided is the substrate for cell culture having a surface formed by grafting a polymer chain including a hydrophili...
For the development of chlorine-resistant nanofiltration membranes, a thin-film-composite membrane was prepared by the interfacial polymerization of N-phenylethylenediamine and 1,3,5-benzenetricarbonyl trichloride on a microporous polysulfone support substrate. The polymerization on the substrate surface was confirmed by Fourier transform infrared...
The chlorine resistance of polyamides synthesized using various diamines and acid chlorides was investigated. The retention ratio of molecular weight and the polymer weight loss after the immersion in chlorine solution were used as the evaluation for chlorine resistance. The influence of the diamine chemical structures on the chlorine resistance is...
A novel evaluation of the separation performance of nanofiltration (NF) membranes for the mixed electrolytes solution was proposed. In the evaluation, the observed transmission of an ion through a NF membrane was used to express the separation performance of the membrane for the ion in the mixed electrolytes solution, which had a relationship with...
Many investigations showed that the dependence of the separation performance of nanofiltration (NF) membrane for the single salt with Mg2+ or Ca2+ on the salt concentration was distinguished from that for the salt with Na+ or K+. In this paper, the results of the permeation experiments of some single salt solutions with Mg2+ or Ca2+ through ESNA 1...
A new model is proposed to evaluate the separation performance of nanofiltration (NF) membranes for the mixed salts solution. In the model, the observed transmission of an ion through a NF membrane is applied to express the separation performance of the membrane for the ion in the mixed salts solution, which has a relationship with the total concen...
Permeation experiments of binary electrolyte solutions of NaCl, NaNO3, CaCl2 and Ca(NO3)2 through three kinds of NF membranes (ESNA 1-LF, ESNA 1 and LES 90) were carried out to investigate the effects of the ionic species and their interactions on the rejections of the NF membranes. The experimental results indicate that the observed rejections of...
We have investigated structural changes in a poly(vinyl alcohol) (PVA) film during uniaxial stretching in water by conducting simultaneously the tensile stress−strain measurement with small-angle X-ray scattering (SAXS) using our newly developed drawing apparatus for the in situ SAXS measurements. Below the strain of 70%, the crystalline lamellae o...
Formation kinetics of polyphthalazine ether sulfone ketone (PPESK) membrane via wet phase inversion process has been studied experimentally and theoretically. The membrane morphology has been observed using an online optical microscope–CCD camera experimental system and the precipitation front move X, has been measured. Three different linear corre...
Formation kinetics of the poly(phthalazinone ether sulfone ketone) (PPESK) asymmetric membrane via wet phase-inversion process has been studied experimentally. The membrane morphology has been observed using an online optical microscope–CCD camera experimental system. The precipitation front movement, X, has been measured. Three different linear co...
Investigations have revealed the permeation performance of electrolytes in the separation process by nanofiltration membranes in single salt solutions. However, there is still not much information about the separation process of mixed electrolyte solutions, and by now most of the investigations have been on solutions containing three kinds of ions,...
Nanofiltration (NF), which has been largely developed over the past decade, is a promising technology for the treatment of organic and inorganic pollutants in surface and ground waters. The ESNA 1 membrane from the Nitto Denko Corporation of Japan is made of aromatic polyamide, which provides salt rejection from 50% to 90%. In this paper permeation...