Green hydrogen energy has attracted increasing attention in relation to climate change and energy issues. In this case, hydrogen must be produced without carbon dioxide emission. Water is the only raw material that can be obtained cheaply and in large quantities to produce such hydrogen. The splitting of water into hydrogen and oxygen requires an increase of Gibbs energy by 237 kJ/mol at room temperature and ambient pressure. The energy is usually supplied as electrical or light energy. This review focuses on the development of particulate photocatalysts that use the energy of sunlight to split water. After explaining the basic principles required for semiconductor particulate photocatalysts for water splitting, the development of several photocatalysts will be described in detail. The development of a total system to produce solar hydrogen from sunlight and water using particulate photocatalysts is then described, especially with the emphasis on the hydrogen separation system from hydrogen and oxygen mixture using membrane. Finally, the remaining challenges for the practical application of this novel technology are described.

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Global freshwater demand is projected to increase, highlighting the growing importance of efficient membrane– based water reuse and advanced treatment technologies. While MF, UF, and RO systems can produce high–quality treated water, they face operational challenges such as fouling, scaling, and high energy consumption. In this study, we introduce the real–time water quality sensing platform “S.sensing” to optimize the dosing of coagulants and RO treatment chemicals. Furthermore, by leveraging AI–driven multi-objective optimization to reduce energy consumption and improve operational uptime, we contribute to the advancement of sustainable and cost–effective membrane treatment technologies.

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To enhance CO2 separation performance in polyimide membranes, we investigated polymers containing rigid six–membered ring structures. An ensemble learning approach combining linear models, decision trees, and neural networks was used to predict initial CO2 and CH4 permeabilities, aged CO2 permeability, and solubility in N– methyl–2–pyrrolidone (NMP) from molecular descriptors, solubility parameters, and glass transition temperatures. Among 31 predicted candidates, 10 polymers were synthesized and experimentally evaluated. The separation performance aligned well with predictions, while the accuracy of solubility predictions remained limited, indicating the need for further model refinement.

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Membrane technology plays a key role in sustainable development of water treatment. With digital transformation (DX), advanced techniques such as real–time monitoring and predictive control using sensors and AI have been introduced. Materials informatics (MI) is gaining attention as a core technology for accelerating membrane material development. Recent studies show that combining molecular–level simulations with data–driven modeling can improve the accuracy of property prediction and support the design of high–performance and antifouling membranes. In this article, we report a recent progress of DX & MI that uses machine learning and simulation to explore structure–property relationships and enables efficient screening of new materials.

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Japan’s centralized water infrastructure faces critical challenges, including a declining population, aging facilities, and the impacts of climate change, necessitating a paradigm shift towards decentralized, off–grid systems like Point of Use (POU). This paper presents three innovative membrane–based technologies designed to construct a next–generation, sustainable water infrastructure. First, we have developed a water quality visualization technology using a smartphone application that allows citizens to easily and accurately assess water conditions (e.g., pH) from test strips. Second, an autonomous membrane filtration system has been created, which utilizes fluorescence sensors to monitor membrane fouling in real–time and automatically optimize cleaning processes, significantly improving operational efficiency and reducing chemical consumption. Third, we propose a “4D design and production” scheme for membranes, which integrates virtual design and simulation with on–demand manufacturing using 3D printing, enabling rapid development and production of membranes tailored to specific needs. The integration of these technologies– visualization for user trust, autonomous control for maintenance–free operation, and 4D production for flexibility– will pave the way for a resilient and sustainable water–circulating society, transforming the challenges of a depopulating era into opportunities for innovation.

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Cells are the smallest units of life. Biomembranes play an important role in separating the cell interior from the external environment and creating fields of chemical reactions and biosynthesis necessary for maintenance of life phenomena. Membrane curvature formation is observed in various biological phenomena, such as the cellular uptake of nutrients and secretion of extracellular vesicles carrying informative molecules. Curvature–sensing peptides are promising tools that allow us to visualize curved membranes or manipulate biological phenomena. In this review, I would like to introduce the technology and applications of curvature–sensing peptides for detection, isolation, modification, and drug delivery system of extracellular vesicles.

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Lyotropic liquid crystals (LLCs) have been attracting attention as new transdermal drug delivery carriers because of their high stability compared with that of other liquid carriers, such as emulsions, micelles, and liposomes. However, the transdermal delivery performance of LLCs is not satisfactory because their high viscosity often reduces the permeation rate of the drugs. In the present study, to improve the performance of LLCs as a drug delivery carrier, we have developed an ionic liquid crystal (ILC) formulation by adding an ionic liquid (IL) component as a mesogen, which can enhance transdermal permeation. A biocompatible ionic liquid IL[Cho][Ole], composed of choline and oleic acid, was synthesized for pharmaceutical applications. The ILC formulations loaded with 1 wt% of favipiravir (FAV), which had potential as a therapeutic agent for coronavirus infections, showed excellent stability. In vitro drug permeation experiments using mouse skin indicated that the ILCs enhanced the permeability of FAV. In particular, FAV–ILC–70 (IL[Cho][Ole] : water = 7 : 3 (w/w)), which has a gyroid structure, significantly improved the transdermal delivery of FAV by fluidizing the stratum corneum lipids. These results suggest that liquid crystalline formulations with biocompatible ILs are promising new transdermal drug delivery carriers.

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Bipolar membrane electrodialysis can produce inorganic acids and alkalis from inorganic salts, and has been attracting attention due to the recent increase in lithium demand. We focused on the blister problem that can occur during operation, investigated its cause, evaluated its impact on operation, and proposed a method to avoid it. When the alkaline compartment is acid–washed, it is important to control the acid concentration in the alkaline compartment to be lower than that in the acid compartment.

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