Membrane fouling caused by adsorption of foulants onto membrane surfaces is a difficult problem. Shirasu porous glass (SPG) membrane with 25 nm nominal pore radius was used as substrate and the surface of the membrane was modified with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer that is a well-known artificial biomaterial with high anti-fouling properties. The effects of reaction time and polymer concentration on membrane performances were investigated with a cross-flow filtration experiment conducted under various conditions. The membranes treated with MPC polymer showed high anti-fouling properties and high water permeability. And the values of observed rejection for the MPC treated membrane were higher than those for substrate. The change in pore size was estimated by analyzing the flux dependency of real rejection with membrane transport theory. A decrease in pore radius of approximately 10 nm corresponding to the thickness of the polymer chain was obtained.

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In systems for utilizing seawater resources based on the desalination and salt production process, to prevent scaling in reverse osmosis (RO) and electrodialysis (ED) units, the calcium (Ca) recovery and upgrading method was studied. From the viewpoint of solubility of Ca salts, the synthesis of calcium carbonate (CaCO₃) by reactive crystallization between the dissolved Ca^2＋ in seawater/brine and carbon dioxide (CO₂) can be considered as an effective separation/recovery method. Moreover, the obtained CaCO₃ is able to upgrade to hydroxyl apatite (HAP) with treatment of phosphoric acid and hydroxide. In this paper, as a two-stage process of Ca^2＋ recovery, CaCO₃ generation using the dissolved Ca^2＋ ion in the brine solution and CO₂ bubbles, and conversion to HAP were examined. Additionally, in order to simplify and facilitate the process, the one-stage process of HAP generation, including treatment of phosphoric acid and hydroxide, was also investigated. The experimental results in a two-stage process were as follows: 1) when CO₂ bubbles were continuously supplied to the brine solution, only CaCO₃ was crystallized; 2) aragonite fine particles were produced by minimizing bubble size; 3) the suspended CaCO₃ particles in the solution were almost converted to HAP by treatment of phosphoric acid and hydroxide at solution pH of 7.0; furthermore, 4) when the brine solution was treated with phosphoric acid and hydroxide, HAP was generated in the range over 4.7 of solution pH; and 5) the generation rate and crystallinity of HAP increased with an increase in solution pH.

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In a conventional desalination process, with the progression of desalination, i.e., decreasing the concentration of ions, the electrical resistance of the electrodialyzer increases. Here, ion-exchange groups were appended onto the currently-used spacer of the electrodialyzer to enhance ion transport and reduce the electrical resistance of the electrodialyzer. By means of radiation-induced graft polymerization, glycidyl methacrylate was graft-polymerized onto a polyolefin-made spacer with a thickness of 0.8 mm and an aperture ratio of 72 ％, and the produced epoxy group was converted into a sulfonic acid group. The electrical resistance of the sulfonic-acid type ion-exchange spacer with a salt-splitting capacity of 1.4 mmol/g was reduced in the 1.0 mmol/LNaCl concentration by 41 ％ compared to that of the starting spacer.

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Halophilic bacteria living in high salinity environments, i.e., oceans, salt lakes salty foods, etc., produce halophilic enzymes that show high aqueous solubility, strong resistance to protein aggregation, and high refolding and renaturation efficiency. These properties are associated with their abundant net negative charges. Firefly (Photinus pyralis) luciferase is widely used in a variety of applications, but known as an aggregation-prone protein with low stability. Here, we demonstrated that halophilic β-lactamase confers to the firefly luciferase higher solubility and stability as a His-β-lactamase-luciferase fusion protein construct.

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