Nippon Shokubai (Japan)

The development of high-performance membranes for alkaline water electrolysis (AWE) is crucial for scaling up green hydrogen production. Conventional porous diaphragms used in AWE must balance ionic conductivity and gas crossover suppression, where increased porosity enhances conductivity but compromises gas separation efficiency. This study introduces an innovative membrane with selective gas permeability, enabling efficient operation under industrial conditions with enhanced durability.The proposed membrane exhibits anisotropic gas permeability, meaning it preferentially suppresses gas crossover in one direction more than the other [1]. This effect is achieved by a unique asymmetric structure, where one side of the membrane is smoother and denser, acting as an effective gas barrier, while the other side remains more porous to maintain high ionic conductivity. Notably, the membrane's ionic resistance (0.2 Ω cm²) is comparable to that of the commercial Zirfon Perl UTP500 diaphragm, while simultaneously demonstrating superior gas crossover mitigation.To assess performance, the membrane was tested in a 4-cell alkaline water electrolyzer stack under various operating conditions. Gas purity measurements confirmed that the membrane orientation significantly influences gas separation efficiency. In orientation-2 (smooth side facing the anode), H₂ permeation to the anode side was significantly reduced, as shown in Figure 1(a), while maintaining hydrogen purity above 99.6 vol% even at low current densities. Conversely, in orientation-1 (smooth side facing the cathode), H₂ purity approached nearly 100 vol% due to the substantial suppression of oxygen crossover, as illustrated in Figure 1(b). Furthermore, the flux density of permeated H₂ remained largely unaffected by current density in both orientations, as shown in Figure 1(c), indicating that hydrogen crossover was primarily governed by diffusion rather than electrochemical driving forces. In contrast, the flux density of permeated O₂ increased significantly with current density in orientation-2, as depicted in Figure 1(d), suggesting a strong correlation with electro-osmotic drag effects. These results highlight the membrane’s ability to extend the operational range of alkaline electrolyzers while reducing the risk of explosive gas mixtures.The durability of the membrane was evaluated over 900 hours of continuous operation at 1.0 A cm⁻² in 7 M KOH at 60 °C, demonstrating stable performance without significant degradation. Furthermore, pre-treatment studies revealed that soaking the membrane in pure water for one day significantly improved its ionic conductivity, making it compatible with commercial electrolyzer systems.This research demonstrates that integrating a selective gas permeability membrane into alkaline water electrolyzers can enhance efficiency, improve hydrogen purity, and extend operational flexibility, particularly under fluctuating renewable energy conditions. These findings contribute to the advancement of low-cost, durable, and scalable electrolysis technologies, supporting the widespread adoption of green hydrogen in a future hydrogen economy. Acknowledgments: This research was partially supported by JPNP 20003 project that was commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

Mechanochemical organic synthesis have recently attracted attention as a novel approach for the synthesis of nanocarbon materials. In this study, we report on the mechanochemical carbonization of phloroglucinol (PG) with accelerated furan cyclization to achieve structural control of soluble carbon materials (SCM). By employing a mixer mill with external heating and optimizing the addition of water as an additive, we successfully promoted the formation of furan ring structures within the carbon framework. Raman spectroscopy revealed that the combination of mechanical energy, heating, and water addition is essential for the selective formation of furan rings, leading to SCM with high solubility and well-defined functional groups. This method eliminates the need for a separate pyrolysis step and enables the direct synthesis of structurally controlled SCM. The resulting materials are expected to serve as promising candidates for applications such as metal ion ligands and adsorbents. Our findings provide new insights into the bottom-up design of functional carbon materials via mechanochemical processes.

The sequestration of CO2 into mineral carbonates via wet carbonation offers a promising pathway for carbon capture and storage, particularly when it is applied to recycled cement paste (RCP) materials. Traditionally, this involves a two-step process: Ca2+ extraction using additives such as amines, followed by carbonation. In this study, we explored a one-step direct wet carbonation method using ethylenediamine (EDA) at dosages of 1, 5, and 10% to control the crystallization behavior and polymorphism of calcium carbonate. A high degree of carbonation, approximately 0.9, was achieved at 5 and 10% EDA. Amorphous calcium carbonate (ACC) formed at all dosages, with the highest amount observed at 5%. Depending on EDA concentration, ACC subsequently transformed into calcite (1%) or vaterite (5 and 10%). This polymorphic evolution is governed by Ca2+-EDA complexation, which modulates calcium supersaturation and thus affects carbonation kinetics and crystallization pathways.

Abstract We report the syntheses of novel marine biodegradable poly(ethylene succinate) (PES)- and poly(butylene succinate) (PBS)-based copolymers containing different dicarboxylic acid (DCA) units with various carbon numbers and different feed ratios. Biochemical oxygen demand tests demonstrated that some of the obtained PES- and PBS-based copolymers were biodegradable in seawater. Specifically, polymers with longer-chain DCA units, even at low contents, exhibited marine biodegradability. The thermomechanical properties of the copolymers, such as their thermal stabilities, melting points, glass transition temperatures, tensile moduli, strains at break, and stresses at break, also varied with the DCA contents. These results indicated that the thermomechanical properties and the marine biodegradabilities of the PES- and PBS-based copolymers were regulated by controlling their structures and DCA contents. The polymers obtained in this study may replace general-purpose polymers. Our approach may also be applicable to other polymeric materials. Furthermore, our findings pave the way for the rational design and preparation of polymeric materials that are biodegradable in environments other than oceans and have good thermomechanical properties.

Local residents and tourists of Kume Island suffer from the biting of Leptoconops taiwanensis (Lien, Lin & Weng 1998) (Ceratopogonidae), a species known as asa-mushi (sea lettuce bug). Because L. taiwanensis bites tend to occur while harvesting sea lettuce, some locals mistakenly believe that L. taiwanensis inhabits the sea lettuce. The objectives of the current study are to (i) identify the chironomid species inhabiting the sea lettuce, (ii) determine the distribution of the larvae, and (iii) perform a faunistic investigation of Chironomidae at Shinri Beach. Only one male chironomid species, Ainuyusurika tuberculatum (Tokunaga, 1940), emerged from the samples taken from the beach. The density of chironomid larvae was the highest in the presence of sea lettuce. A total of 53 males were collected using light traps, of which we identified males of seven genera and seven species belonging to three subfamilies. No L. taiwanensis were collected in this study.

The Bacillus thuringiensis (Bt) toxin targets lepidopteran, dipteran and coleopteran pests. Despite their close taxonomic relationship to Lepidoptera, few studies have examined the hazard of Bt toxins on Trichoptera. We performed laboratory exposure tests to examine the effects of Bt var. aizawai on filter-feeding caddisflies, particularly Stenopsyche marmorata. In the continuous exposure test, the mortalities ranged from 0% at 1 mg/l to 100% at 20 mg/l 24 hours after exposure to Bta. The mortality at each concentration increased from 24 to 48 hours. In limited contact, mortality increased with contact time. Acclimatisation and water quality also affected larval mortality. Our results suggest that higher concentration and longer exposure to Bta affect or affect the increase of larval mortality.

Abstract Antimicrobial surfactants contained in mouthrinse have excellent efficacy but are not retained on the tooth surface (are rinsed away) due to their low water resistance and thus do not exhibit sustained antibacterial activity. We have developed a new coating method using graphene oxide (GO) that retains the surfactant on the tooth surface even after rinsing with water, thus providing a sustained antibacterial effect. Ultra-thin films of GO and antimicrobial agent were prepared by (1) applying GO to the substrate surface, drying, and thoroughly rinsing with water to remove excess GO to form an ultrathin film (almost a monolayer, transparent) on the substrate surface, then (2) applying antimicrobial cationic surface active agents (CSAAs) on the GO film to form a composite coating film (GO/CSAA). GO/CSAA formation was verified by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and ζ-potential and contact angle measurements. GO/CSAA was effective at inhibiting the growth of oral pathogens even after up to 7 days of storage in water, and antibacterial activity was recovered by reapplication of the CSAA. Antibacterial GO/CSAA films were also formed on a tooth substrate. The results suggest that GO/CSAA coatings are effective in preventing oral infections.