A braid adsorbent having the functional group of amidoxime is a promising material for the recovery of uranium (U) dissolved in the seawater. This long braid adsorbent was made by polyethylene multi-fibers in which amidoxime groups were introduced by radiation-induced graft polymerization and a subsequent chemical treatment. The braid adsorbent obtained was moored at the offing of Okinawa Island. The average U adsorption of the adsorbent became 1.5g-U/kgadsorbent for 30d soaking.The mooring system for braid adsorbent has possibility which reduced the cost for the recovery of U from seawater. Annual product of 1,200 tons of U needs 134km²of mooring area. In addition, there is 6,000 km² and more of suitable sea area for the collection of the U in the regions from Okinawa Islands to Tosa Bay in Japan.

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A membrane type adsorbent of spinel-type manganese oxide was prepared by a solvent exchange method with poly (vinyl chloride)(PVC) as a binder. A new type adsorption apparatus suitable to the membrane-type adsorbent was designed for obtaining a parallel seawater flow along the membrane. Placing the membrane between spacers was found to be effective in raising the lithium adsorption rate. The adsorption efficiency and the pressure loss depended to the kind of spacers used; the plane-weave-form spacer with 0.9 mm thick showed the highest recovery efficiency although the pressure loss was relatively high.

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Rare metals such as vanadium and cobalt are dissolved in seawater at very low concentrations. Ascidians are known to accumulate extremely high levels of vanadium selectively. Vanadium is accumulated mainly in one type of their blood cells, and the concentration reaches 350 mM corresponding to10⁷times that in seawater. Recently, we isolated vanadium-binding proteins, Vanabinl-5, from an vanadium-rich ascidian, Ascidia sydneiensis samea. Biochemical and structural analyses revealed that Vanabins make a novel protein family which is characterized by 18 conserved cysteine motif. They are thought to act as metal chaperones in ascidian blood cells. Vanabins can be used as an agent for selective bioaccumulation and biosorption of heavy metals.

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Novel ion-exchange membranes, which can control their hydrophilicity in response to temperature changes, are prepared by casting dimethyl sulfoxide solution of mixed poly (vinyl alcohol)(PVA), polyelectrolytes, and in situ polymer of PVA and N-isopropylacrylamide (NIPAAm). The water content of the membranes decreases with increasing temperature. This indicates that the hydrophilicity of the membrane matrix can be controlled by changing the temperature. The charge density of the membranes increases with temperature. The permselectivity through the membranes, which is defined as the division of permeation coefficient of NO₃^- ion to that of F- ion, increases at 50°C, but decreases at 15°C with increasing poly (NIPAAm) content. This indicates that the permselectivity between the ions through the membranes can be controlled by changing the temperature and the poly (NIPAAm) content.

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A calix [4] arene carboxylic acid derivative was utilized as an extractant for alkaline metal ion separation. The host compound exhibited a high extractability to sodium ion compared to lithium ion and potassium ion. We also discussed the experimental results with a computational modeling by means of semi-empirical and ab initio molecular orbital methods. From the molecular geometries and heat of formation of the calix [4] arene derivative before and after extraction, the important factors for alkaline metal ion separation were found to be its cyclic structure and its cavity size.

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We monitored the seasonal changes of the abundance and composition of microorganisms in organically enriched sediment deposited just below the net pens for fish culture, using the quinone profiling method. We attempted to treat the sediment by scattering the cultured colonies of a smalldeposit feeding polychaete, Capitella sp. I which favours organically enriched sediment. Approximately9.2 million individuals of the cultured colonies of Capitella were placed on the sediment in an area of 144 m ² just below a net pen in a fish farm in November 2004, increased very rapidly, and reached densities of 317,000 ind./m² by January 2005. In this fast-increasing process of Capitella, the respiratory quinones including ubiquinone (UQ) and menaquinone (MK) in the surface sediment up to 2 cm in depth, also markedly increased in the sediment with Capitella, and reached 10.9 nmol/g-dry sediment in January 2005, although the water temperature decreased to its lowest levels all year. The respiratory quinones in the surface sediment up to2 cm in depth were approximately 7.0 times larger than those outside the fish farm. In particular, the percentage of UQ-10, which was contained in α subclass of Proteobacteria, increased by 9.5%and 4.1%in the layers of the sediment of 0-2 cm and 2-4 cm in depth, respectively, during this period. These facts sugget that the bacterial growth is markedly enhanced by the biological activities of the worms in the sediment, and the rapidly increased bacteria also play an important role in the decomposition of the organic matter in the sediment with extremely high density patches of Capitella from the organically enriched sediment.

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In upward spray flash desalination system, the experiment is carried out to clarify the influence of jet flow and jetdistribution pattern.
An superheated water at temperature of 24.0, 30.0, 35.0, and 40.0°C is injected upward into a depressurized chamber through a cylindrical nozzle with the internal diameter of 83.1mm.The range of the mean velocity of the superheated water is from1.2 to 3.6m/s. The horizontal temperature distribution of the upward jet is measured by 10 thermo resistances, which are movable along the jet axis, at 26 locations between 0.0mm and 700.0mm from the nozzle exit.
The results show that the upward jet flash evaporation is classified into 4 patterns called liquid film, cyclic, droplet, and spray evaporation. By the dimensionless arrangement, the horizontal temperature distributions of the upward jet are categorized into 2 types. The approximate equations are proposed to estimate the area of influence from the flash evaporation by a nozzle.

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