The behavior of radicals in polyethylene film in electron-beam-induced graft polymerization was studied. Four kinds of polyethylene film, namely, ultra-high molecular weight polyethylene （UHMWPE）, high-density polyethylene （HDPE）, low-density polyethylene （LDPE）, and LDPE-containing HDPE, were selected for the study. These polyethylene films were irradiated with an electron beam to quantify the radical concentrations in the polyethylene films. The radical concentrations in the polyethylene films were found to increase with increases in the electron beam irradiation dose. For a given irradiation dose, the radical concentration in the polyethylene films increased in the order of UHMWPE > HDPE > LDPE-containing HDPE > LDPE. This corresponded to the increase in the degree of crystallinity of the polyethylene films. The polyethylene films were irradiated with an electron beam to graft polymerization. The degree of grafting was found to increase with increases in the radical concentration in the polyethylene film. The relationship between the radical concentration in the polyethylene film and the degree of grafting exhibited the same tendency, irrespective of the degree of crystallinity of the polyethylene film. The degree of grafting could be controlled, therefore, according to the radical concentration in the polyethylene film. After being irradiated with an electron beam, the polyethylene films were stored at temperatures ranging from －80 to 20 ℃, in the atmosphere. As a result of being stored at 20 ℃ in the atmosphere, the radical concentration in the irradiated polyethylene films decreased over time. The residual ratio of radicals in the polyethylene film after being stored for 6 h decreased in the order of UHMWPE > HDPE ≥ LDPE-containing HDPE > LDPE. The rate of decline in the radical concentration in the polyethylene films decreased as their degree of crystallinity increased. When the irradiated polyethylene films were stored at －80 ℃ in the atmosphere, the radical concentration in the polyethylene film after being stored for 24 days was the same as that when the films were initially placed in storage. The radical concentration could be maintained indefinitely by storing the polyethylene films at －80 ℃.

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In recent years, forward osmosis （FO） has been attracting attention as a new energy-saving water treatment technology. In order to put the FO process to practical use, it is indispensable to develop the optimum DS and construct a low energy regeneration process. In this work, we synthesized 6 kinds of ionic liquids with imidazolium-based cations for the purpose of developing ILs-type DS showing UCST-type phase transition at 30 to 50 ℃. As a result of drawing a phase diagram for 11 types of ILs, including commercially available ILs, ［Im（1.0.5）］［BF4］, ［Im（1.1.5）］［BF4］ and ［Im（2.0.4）］［BF4］ showed good phase transition characteristics. As a result of further evaluation of the osmotic pressure performance, ［Im（2.0.4）］［BF4］ demonstrated higher osmotic pressure than seawater as a driving force for forward osmosis and low osmotic resistance in post-treatment with an RO membrane. It was shown that ［Im（2.0.4）］［BF4］ can be applied as DS used for seawater desalination using the FO method.

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For prediction of and countermeasures against salt damage, it is necessary to obtain knowledge of wall surface adhesion behaviors of Cl^－, which is one of the main factors. The behaviors of modeled seawater droplets in relation to Ni wall surface and the concentration behavior on the wall surface were evaluated by molecular simulation. When micro seawater droplets were impacted to the wall surface at different initial velocities and NaCl concentrations, the droplet shape depended only on the NaCl concentration, not on the initial velocity. The contact areas of the droplet on the wall increased based on two types of power functions for contact time. At the beginning of adhesion, it was proportional to 0.20 power of the time, and after a certain period of the time, it was proportional to 0.089 power of the time. Next, when the temperature of the wall surface was raised, water evaporation and NaCl cluster formations were observed. The evaporation rate of water increased from the center to the outside, and during the falling-rate drying period, the evaporation rate on the outside was twice as low as that in the center. In the evaluation of NaCl clusters, when the temperature of the wall surface was raised, the cluster’s size decreased, and it was possible to calculate the cluster concentration, which is important for predicting salt damage.

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