Nitto Denko Research Articles

The tolerance of a thin-film composite polyamide reverse osmosis membrane to hydrogen peroxide exposure

Understanding the tolerance of thin-film composite (TFC) polyamide (PA) membranes to hydrogen peroxide (H2O2) is prerequisite to evaluate its use as biofouling control agent in reverse osmosis (RO) systems. H2O2 is potentially an alternative to the commonly applied chlorine-based disinfectants hypochlorous acid (HOCl) and monochloramine (MCA) that degrade PA membranes and form disinfection byproducts. The tolerance of the PA separation layer of a commercial RO membrane (ESPA2, Nitto Denko Hydranautics, Oceanside, USA) to H2O2 exposure was evaluated using a recirculating flat-sheet RO test system under corrosion-suppressed conditions. Membrane samples were exposed to 2.0mM (68mg/L), 10mM (340mg/L), 25mM (850mg/L) and 50mM (1,700mg/L) H2O2 for up to 24 days at 25°C in phosphate buffer at pH 7.2 without and with methanol present. Membrane performance was evaluated by measuring water flux and rejection of phosphate buffer and acesulfame (ACE), a common organic wastewater indicator compound. Membrane breakdown was assessed by water flux increase and loss of solute rejection. Without methanol, the membrane was stable in 1,700mg/L for at least 18 d, corresponding to a maximum tolerated dose (Dmax) of >744,000ppm-h. At initial concentrations of 20mM methanol and exposure to 850mg/L and 1,700mg/L H2O2, membrane breakdown occurred after approximately 18 days and 10 days, corresponding to Dmax of 367,200ppm-h and 408,000ppm-h, respectively. The time to membrane breakdown was defined as decrease of salt rejection of at least 0.5% within 24h. Membrane characterization employing X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy with Energy Disperse X-ray spectroscopy (SEM-EDS) failed to reveal membrane oxidation.

Avecia builds up drug service business

Nitto Denko Avecia will acquire Irvine Pharmaceutical Services, an analytical development services provider, and sister company Avrio Biopharmaceuticals, a contract manufacturer of injectable drugs. Both firms are located in Irvine, Calif. Avecia is a contract manufacturer of oligonucleotides with facilities in Massachusetts and Ohio. President Detlef Rethage says the purchase will broaden Avecia’s services for drug industry customers beyond oligonucleotide manufacturing.

KINESIOTAPING W LECZENIU OBRZĘKU LIMFATYCZNEGO KOŃCZYNY GÓRNEJ U PACJENTKI PO OPERACJI RAKA PIERSI – STUDIUM PRZYPADKU

The aim of this study was to examine the effectiveness of lymphatic kinesiotaping in patients after unilateral breast cancer surgery. Complex decongestive therapy in patients after right-side breast-conserving surgery was done once a week for 2 months (from November to December 2014). It involved manual lymph drainage and lymphatic application of kinesiotaping. An original kinesiology tape (Nitto Denko, Japan) was used for the treatment. Lymphoedema was measured at the beginning and at the end of treatment in centimetres in specific places: metatarsal, wrist, at the mid-length of the forearm, in the elbow and at the mid-length of the upper arm. The volume of oedema was assessed at the beginning and at the end of the treatment. The reduction of lymphoedema in different places. Kinesiotaping may be an alternative method in relation to the use of materials in complex decongestive therapy. However, this technique requires further research.

Kinesiology Taping in Cervical Vertigo Treatment

Introduction: In otoneurological clinical practice, cervical vertigo is one of the most common vestibular disorders. Purpose: The aim of this study was to evaluate the effectiveness of Kinesiology Taping in patients with cervical vertigo syndrome, based on an objective assessment of spinal conduction from the balance system sensory receptor (SEP test), a postural control based on a cranio-corpography (CCG test) and Freyss’ dynamic stabilometry. Methods: The research covered 74 patients. Through medical examination all the patients were diagnosed with vertigo of somatosensory etiology (disturbed somatosensory evoked potentials – SEP on a cervical level) or of mixed etiology (disturbed SEP and vasogenic cervical disorders). Kinesiology Taping, using Strips by Nitto Denko Kinesiology Tape / K-Active Tape, was applied to both groups of patients. Somatosensory evoked potential (SEP) test, craniocorpography (CCG), Freyss’ stabilometry test were performed before and after therapy. Results: The results were compared before and after kinesiotaping in patients and between the patients and control group of healthy subjects. With regard to the SEP test, waves N13, P11 and P27 latency measurement results obtained after rehabilitation did not show any statistically important differences, as compared with the control group. In the case of the CCG examination there was no improvement after rehabilitation. Significant differences were observed on Freyss’ stabilometry under the condition of visual control and comparing the groups of strictly somatosensory and mixed cervical vertigo. Conclusions: In patients with cervical vertigo, the applied Kinesiology Taping therapy did not have an impact on the objectively measured parameters of SEP, but caused the positive effect on balance coordination measured by stabilometry. Patients with solely somatosensory etiology of balance disorders responded better to the taping therapy than patients from the mixed etiology group.

Nanofiltration of treated digested agricultural wastewater for recovery of carboxylic acids

Synthetic solutions of varying concentrations of carboxylic acids, namely acetic and butyric acids (50 mM, 100 mM) and treated digested agricultural wastewater with a carboxylic acids concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid were processed with a range of nanofiltration membranes and enrichment schemes to concentrate carboxylic acids. The study was conducted with the scope of platform chemicals recovery from complex effluents, investigating the feasibility of nanofiltration as a method of choice. Membrane filtration is easily scalable into various arrangements, allowing versatility in operation and enrichment treatments, which other recovery practices such as liquid extraction do not allow. Among the five nanofiltration membranes used (NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA), LF10 (Nitto Denko, Japan)) the DK, DL and NF270 were identified as the best candidates for carboxylic acids separation and concentration from these complex effluents, both in terms of retention and permeate flux. These membranes achieved retention ratios, up to 75% giving retentates up to 53.94 mM acetate and 28.38 mM butyrate for the agricultural wastewater. Effluents were modified by the addition of alkali and salts (sodium chloride and sodium bicarbonate), and it was found that highest productivity, retention and flux was achieved at pH 7 but at higher pH there was a significant reduction in flux.

Synthesis and characterization of a layered-hybrid membrane consisting of an organosilica separation layer on a polymeric nanofiltration membrane

In this study a new type of layered hybrid membrane was fabricated. This new membrane consisted of a thin organically bridged silica separation layer deposited onto the surface of a flexible polymeric membrane, NTR-7450 (Nitto Denko, Japan), and was comprised of a sulfonated polyethersulfone top layer and a porous polysulfone support. Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a precursor, a continuous and defect-free BTESE separation layer was deposited onto the surface of a polymeric nanofiltration membrane via a facile, reproducible and scalable sol–gel spin-coating and low-temperature curing process. First, the optimal preparation conditions were established, which included the curing temperature and the spin-coating cycles. The membranes were then used for the vapor permeation dehydration of isopropanol-water solutions, and showed a stable water flux of 2.3kg/(m2h) and an improved separation factor of about 2500, which was an increase of approximately 5-fold compared with that of a polymeric nanofiltration membrane. In addition, single-gas permeance through this membrane was also discussed and a modest H2/N2 selectivity of 26 was obtained, which approximated the performance of ceramic-supported BTESE-derived silica membranes.

Recovery of volatile fatty acids (VFA) from complex waste effluents using membranes

Waste effluents from anaerobic digesters of agricultural waste were treated with a range of membranes, including microfiltration and nanofiltration (NF), to concentrate volatile fatty acids (VFA). Microfiltration was applied successfully to produce sterile, particle-free solutions with a VFA concentration of 21.08 mM of acetic acid and 15.81 mM of butyric acid. These were further treated using a variety of NF membranes: NF270 (Dow Chemicals, USA), HL, DL, DK (Osmonics, USA) and LF10 (Nitto Denko, Japan), achieving retention ratios of up to 75%, and giving retentates of up to 53.94 mM of acetate and 28.38 mM of butyrate. DK and NF270 membranes were identified as the best candidates for VFA separation and concentration from these multicomponent effluents, both in terms of retention and permeate flux. When the effluents are adjusted to alkali conditions, the highest productivity, retention and flux were achieved at pH 7. At higher pH there was a significant reduction in flux.

Separation of three divalent cations (Cu2 +, Co2 + and Ni2 +) by NF membranes from pHs 3 to 5

Separation mechanisms for the three model divalent cations with very similar atomic weights (Cu, 63.5Da; Co, 58.9Da and Ni, 58.7Da) by two nanofiltration (NF) membranes (Nitto Denko ESNA and GE Osmonics DK) were studied in a cross flow module from pHs3 to 5. The results show that the rejection order for the two selected membranes was Ni2+>Cu2+>Co2+ from the conducted experiments, and the removal efficiency was increased as pH was decreased for all three metals. It was found that enthalpy of hydration and concentration polarization exerted the controlling effect on the membrane selective transport rather than atomic weight, Stokes radius and hydrated radius. Besides, the counterion of sulfate enhanced the removal efficiencies, but an increase of sulfate more than 0.01M reduced the removal efficiencies. Moreover, the removal efficiency of DK membrane was better than that of the ESNA membrane due to the positive charge of DK membrane at low pH.

HYDRAcap® MAX: innovative micro-filtration for reverse osmosis pretreatment and water reuse

Hydranautics has been a manufacturer of organic membranes for more than 30 years and has always been a technology leader. Being part of the Nitto Denko Group since 1987, hydranautics has inherited Nitto Denko’s innovative philosophy. In September 2011, hydranautics announced the commercialization of its new PVDF hollow fiber microfiltration module: HYDRAcap® MAX. This new out/in module features one of the highest membrane areas currently available in the industry. Furthermore, HYDRAcap® MAX offers an air scour (AS) mode that allows the designer to eliminate the backwash sequence and pump; this results in increased recovery and lower capital expenses. The key applications for HYDRAcap® MAX are reverse osmosis pretreatment and water reuse, for both industrial and municipal applications from various types of water sources.This study will introduce HYDRAcap® MAX technology and its advantages, including higher membrane area resulting in lower footprint and innovative design resulting in optimized recovery. It will also discuss the operating sequences (i.e. filtration, AS, and cleanings), provide data from a case study, and give an example of a medium size system.

Molecular Gate Membrane: Poly(amidoamine) Dendrimer/polymer Hybrid Membrane Modules for CO2 Capture

Japanese government declared a goal to reduce CO2 emissions to half of those in 2005 as the objective “Cool Earth 50”. One promising means of reducing CO2 emission is the development of integrated coal gasification combined cycle with CO2 capture & storage (IGCC-CCS). In the IGCC-CCS process, CO2 separation membranes will play an important role for reducing CO2 capture costs. Estimates indicated that the CO2 capture cost from a pressurized gas stream using a membrane would be 1,500 JPY/ton- CO2 or less.We are currently developing CO2 molecular gate membrane, with the goal of producing a new, high-performance separation membrane modules. In the concept of the molecular gate membrane, the pathway for gas molecules is occupied solely by CO2, which acts as a gate to block the passage of other gases. Consequently, the amount of H2 permeating to the permeate side of the membrane is greatly limited and high concentrations of CO2 can be obtained. Poly(amidoamine)(PAMAM) dendrimers, candidate materials for molecular gate membranes, shows high separation performance in separation of CO2/N2 and CO2/H2. In RITE, PAMAM dendrimer/polymer hybrid membranes were developed for CO2 separation from flue gas (CO2/N2) and from IGCC process (CO2/H2). Although dendrimer itself is viscous liquid, the dendrimer/polymer hybrid membranes are stable under pressure difference conditions, and thus suitable for practical use. The CO2/H2 selectivity of the membrane showed more than 30, which is required to apply membrane modules for IGCC process. From these results, a PAMAM dendrimer/polymer hybrid membrane is a promising candidate for IGCC process with CO2 capture. Based on these materials, modification of membrane materials is ongoing to improve CO2 separation performance further.In the development of commercial membrane modules using the PAMAM dendrimer/polymer hybrid materials, RITE, Kuraray Co., Ltd., Nitto Denko Corporation and Nippon Steel Engineering Co., Ltd. established Molecular Gate Membrane module Technology Research Association, and membrane materials, membrane modules and separation systems are being developed with collaboration in the research association.

Potential of Membrane Separation Processes in Cheese Whey Fractionation and Separation

Recently, membrane separation techniques are extensively used in a dairy industry, which contains many valuable substances (proteins, lactose, minerals) which can be further used, e.g. in food industry or biotechnologies. This paper summarises a potential of membrane separation process, namely ultrafiltration and nanofiltration, in fractionation of whey components, such as proteins and lactose. It also brings data from desalination of lactose from natural salty whey (from various Czech dairies). Whey was treated by pilot-plant ultrafiltration (Bollene, France) on tubular ceramic membranes (Membralox, Pall) and obtained permeates were purified by nanofiltration spiral wound membranes. We compared two different commercial nanofiltration membranes NTR-7450-S2F (Nitto Denko) and FILMTEC NF270-2540 (Dow) under various conditions. Permeate flow rates on the 500 nm ultrafiltration membrane achieved 6.9 – 44.5 L/h.m2.bar and mass concentration factors were 1.2 – 16.5. This value suggests potential industrial application. Lactose apparent rejections on NTR-7450-S2F were in a range of 82 – 98% and slightly lower (82 – 90%) on the FILMTEC NF270-2540 membrane. Rejections of ions were comparable for both membranes. All experiments confirmed severe membrane fouling on both membranes.

Singapore applies itself to science

Despite its small size, the Lion City has become an influential exemplar of investing in science to promote industry.

Industry Watch

Phosphagenics Collaboration to Develop Psoriasis Drug. Yabao Pharmaceuticals and Frontage Laboratories Sign Collaboration. QIAGEN Establishes Subsidiary in India to Accelerate Expansion. Bayer and Zydus Agree on New Pharma JV. Codexis Signs First Japanese Biocatalysis Collaboration with Dainippon Sumitomo Pharma. Nitto Denko Acquires Avecia Biotechnology. Particle Sciences and HORIBA Instruments Form Strategic Relationship. New NUS Spin-Off to Develop Novel Electrocardiogram.

Physicochemical properties and biocompatibility of a polymer-paclitaxel conjugate for cancer treatment

BackgroundPoly(L-γ-glutamylglutamine) paclitaxel (PGG-PTX) conjugate is a non-diblock polymeric drug nanoparticle intended to improve the therapeutic index of paclitaxel. The purpose of the present study was to elucidate further the physicochemical properties of PGG-PTX in order to proceed with its clinical development.Methods and resultsPGG-PTX was designed by integration of a hydrophobic paclitaxel conjugate through an added hydrophilic glutamic acid onto poly(L-glutamic acid). The addition of a flexible glutamic linker between PGA and paclitaxel resulted in spontaneous self-assembly of a PGG-PTX conjugate into nanoparticles. The PGG-PTX conjugate was stable as a lyophilized solid form. An in vitro viability experiment showed that PGG-PTX was effective after a longer incubation period, the same trend as Taxol. In vitro studies using NCI-H460 and B16F0 cancer cells demonstrated significantly high cellular uptake after 30 minutes of incubation. The in vivo biocompatibility of PGG-PTX conjugate was evaluated in the NCI-H460 tumor model, the assessment of tissue seemed to be normal after 21 days of treatment.ConclusionThese results are encouraging for further development of non-block polymeric paclitaxel nanoparticles for treatment of cancer.

Novel free paclitaxel-loaded poly(L-γ-glutamylglutamine)–paclitaxel nanoparticles

The purpose of this study was to develop a novel formulation of paclitaxel (PTX) that would improve its therapeutic index. Here, we combined a concept of polymer–PTX drug conjugate with a concept of polymeric micelle drug delivery to form novel free PTX-loaded poly(L-γ-glutamylglutamine) (PGG)–PTX conjugate nanoparticles. The significance of this drug formulation emphasizes the simplicity, novelty, and flexibility of the method of forming nanoparticles that contain free PTX and conjugated PTX in the same drug delivery system. The results of effectively inhibiting tumor growth in mouse models demonstrated the feasibility of the nanoparticle formulation. The versatility and potential of this dual PTX drug delivery system can be explored with different drugs for different indications. Novel and simple formulations of PTX-loaded PGG–PTX nanoparticles could have important implications in translational medicines.

Advancing innovation through R&D the A*STAR way

I. NEED FOR RELENTLESS INNOVATION THROUGH R&D The need to innovate in this rapidly changing economy to create new and higher value is given. At the Agency for Science, Technology and Research A STAR , innovation is our raison d’etre to help create the future of Singapore. Data Storage Institute DSI is one of A STAR’s research institutes RIs . It was established to support the growth of the data storage industry in Singapore. In the early days of DSI in the 1990s, one in two disk-drives worldwide was made in Singapore. Over time, the production of such diskdrives began to move to lower cost countries. DSI continued to develop new capabilities and innovate and supported the shift of the data storage industries toward higher value-added activities. Today, eight out of ten higher value-added high-end enterprise drives and nearly five out of ten hard disk media are manufactured in Singapore. These growth and success of the data storage industry in Singapore have also persuaded key industry players, such as Seagate, Fujitsu, EMC, Seiko, and Nitto Denko, to establish corporate R&D laboratories in Singapore. Seiko and Nitto Denko, in particular, are now colocated with DSI in Fusionopolis—the science and engineering hub in Singapore. We are mindful that these companies will remain in Singapore for as long as we continue to offer a competitive value proposition. This is why DSI has to continue to look ahead to build capabilities to support the key industry players on developing next-generation products such as cost-competitive nonvolatile memory devices and high density magnetic storage at 10 Tbytes / in.2. The challenge therefore is how to do this right by leveraging on what little natural or man-made advantages that Singapore has to sustain Singapore’s competitive advantage. This is the only way for us to achieve our mission to foster world-class research and talent for Singapore in this knowledge-based and innovation-driven world, and it is how we can contribute toward establishing Singapore as Asia’s innovation capital.

Nitto Denko and Mitsubishi Rayon bring to an end their joint-venture company

Japan's diversified materials manufacturer Nitto Denko Corp and Mitsubishi Rayon Co Ltd (MRC), which manufactures speciality chemicals, have brought to an end their joint-venture company dedicated to the development of water treatment membrane technology.

Nitto Denko launches energy-saving RO membrane element

Japan's Nitto Denko Corp, a diversified materials company, and its wholly owned US-based water technology subsidiary Hydranautics have added a high performance and efficient model to the PROC Series of reverse osmosis (RO) membrane elements, which are used to produce pure industrial water from raw water that is heavily loaded with sodium chloride and contaminants.

Absorption of water in the active layer of reverse osmosis membranes

The absorption of water in commercially available reverse osmosis membrane active layers (FT30 by Filmtec and LF10 by Nitto Denko) is investigated by a combination of measurements of water mass uptake and biaxial stress as a function of relative humidity. The experiments are enabled by bonding the active layers of the membranes to either a quartz crystal microbalance or a glass cover-slip using polyimide as an adhesion layer and subsequently removing the porous polysulfone support layer with an organic solvent. Membranes from these two suppliers behave similarly. Water mass uptakes of the active layers are approximately 12% of the mass of the active layer when the relative humidity is changed from 0% to 95%. This degree of water absorption produces a compressive biaxial stress of ≈ −20 MPa. The changes in water mass uptake with relative humidity resemble a Langmuir adsorption isotherm when the humidity is low and the Flory–Huggins theory when the humidity is high. By combining the measurements of water mass uptake and biaxial stress, we estimate that the specific volume of water in the active layers is ≈ 0.28 cm 3 g −1. The self-diffusion coefficient of water in the polyamide active layers of FT30 ( D S = 0.8 × 10 −9 m 2 s −1) and LF10 ( D S = 1.2 × 10 −9 m 2 s −1) were calculated from the water mass uptake measurements, water permeability values reported in the literature and assuming the solution–diffusion mechanism for water transport. These values for D S are a factor of 2–3 smaller than the self-diffusion coefficient of liquid water ( D S = 2 × 10 −9 m 2 s −1) and comparable to theoretical estimates of D S in the active layer of FT30 membrane using the free-volume model.

Arsenic removal by a membrane hybrid filtration system

Arsenic is a toxic semi-metallic element that can be fatal to human health. Membrane filtration can remove a number of contaminants from water, including arsenic. Removal of arsenic by membrane filtration is highly dependent on the species of arsenic and the properties of the membrane. The performance of the nanofilter is better for removing As(V) than As(III). About 57% of As(III) and 81% of As(V) was removed from 500 mg/L arsenic solutions by nanofiltration (NTR729HF, Nitto Denko Corp., Japan) of 700 molecular weight (MW) cutoff. The removal efficiency of microfiltration (MF) was much lower than that of nanofiltration (NF) due to its larger pore size. By comparison only 37% of As(III) and 40% of As(V) were removed by microfiltration (PVA membrane, Pure-Envitech, Korea). However, the removal efficiency of microfiltration was increased dramatically when a small amount of nanoscale zero valent iron (nZVI) was added. The removal efficiency by MF increased up to 90% with As(V) and 84% with As(III) when an amount of 0.1 g/L of nZVI was added into the arsenic solution.