Vol.4 No.3 2012

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Research paper : A novel technology for production of drinking water in emergencies (A. Sonoda)−159−Synthesiology - English edition Vol.4 No.3 (2012) 3 Nitrate ion selective adsorbent “material” (topic for elemental technology needed for outcome realization)3.1 Mass production technology (reproducibility of function)Utilizing the experience of mass-producing similar compounds, Kyowa Chemical succeeded in the mass production of nitrate ion selective adsorbent by incorporating the AIST synthesis method into the industrial method. Although, by experience, Kyowa Chemical was aware of the positive correlation of the nitrate ion selectivity and crystalline property that were determined from the peak strength and half-value width of XRD, it was able to find the optimal synthesis condition when AIST evaluated the nitrate ion selectivity that Kyowa Chemical was unable to evaluate. To avoid clogging the nozzle when shaping, Kyowa’s know-how was used for the pulverization and sifting of the adsorbent reagent, and the specification of particle diameter 45 μm or less, which was required by Teijin Engineering Ltd., was achieved.The stance of conducting the R&D without leaking the corporate know-how to others by clearly setting the product specification, or adsorbent volume of nitrate ion > 1.7 mmol/g – powder adsorbent reagent, distribution coefficient≒ 3000, is important in working with companies that have the technological capability. 3.2 Shaping technology (maintaining the function)When shaping the powder adsorbent reagent, the binder ingredient covers the surface of the adsorbent and its performance decreases dramatically in the ordinary method where the adsorbent reagent and the binder are simply mixed. We conducted the shaping by using the liquid curing method for collecting lithium ion from seawater, but only about 60 % of the adsorbent performance could be obtained[3]. Treatment of large amount was difficult by the contactless supporting method[4] developed by Teijin Engineering Ltd., even when the researcher was resident at AIST Shikoku to conduct joint research over several years, and this was one of the issues.The adsorbent material that could be produced at laboratory scale would not remove the nitrate ions when used in the large equipment at the plant. When this was carefully investigated at AIST, we reached the conclusion that the water, which in this plant was well water used directly, was suspect. We saw improvement by using the pure water line. Because the nitrate ion adsorbent material had high carbonate ion selectivity, the ion exchanging sites on the adsorbent material were all substituted when the adsorbent was washed with well water containing the carbonate ion, and the adsorbent became inactive against the nitrate ion.We considered reviving the adsorbent material that failed to remove the nitrate ion with high concentration of saltwater, and found that it could be revived. That the spent nitrate ion adsorbent material could be used repeatedly was one of the unexpected results. However, it was also found that more pure water was required to produce the drinking water that could be manufactured by the water purification system. Therefore, the use of this system would be limited in times of normalcy. It was also projected that the nitrate ion removal performance would decrease if the carbonate ion was present in the polluted water. 4 Merit of the consortium and the remaining issues for commercialization (synthesis method for outcome realization)Product realization was difficult with joint research with companies only. Therefore, we developed the nitrate ion adsorbent “material” by establishing a consortium and jointly setting the R&D objective. As a merit, the participating industry, government, and academia obtained the research funds as the joiners of the collaboration, and were able to focus on the product realization. By conducting the research using public funds, the private companies were given time limits and obligations, and this allowed them to achieve numerical objectives that they wrote in the proposals and were able to create a basic prototype (Fig. 8).The follow-up research was continued for three years toward product realization. What remained were the developments of the system that instantly determines whether this water purification system can be used effectively, and the system for real time monitoring of the purification capacity. Teijin Engineering, the main body of the commercialization effort, terminated the development of this product in FY 2010. 5 Conclusion (evaluation of the results and future development)Concerning the self-evaluation of achievements, we reached the fourth stage out of ten. It should be reemphasized that the issues that must be solved before commercialization are Fig. 8 Prototype of the mobile water purification system (exhibited at Hannover Messe 2008)Hand pumpHand pumpColumn 2 (removal of ion)Column 2 (removal of ion)Column 1 (removal of organic substance)Column 1 (removal of organic substance)Filter 2(1 µmφ)Filter 2(1 µmφ)Filter 1(50 µmφ)Filter 1(50 µmφ)

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