成果報告書詳細
管理番号20120000000588
タイトル*平成22年度中間年報 最先端PG(Mega-ton Water System) 浸透圧発電 膜素材合成と薄膜形成法の検討(H22~H25)
公開日2012/12/7
報告書年度2010-2010
委託先名国立大学法人東京工業大学
プロジェクト番号P09025
部署名環境部
和文要約和文要約等以下本編抜粋:
全芳香族ポリマー薄膜の開発
本研究では、浸透圧発電の発電効率を向上させるため、高い透水性と高い塩除去率の両立、十分な機械強度と耐薬品性(耐塩素性)を有する正浸透膜の開発を目指している。近年、逆浸透膜素材として既に確立されているポリアミド複合膜の正浸透膜への応用が検討されている。しかし、このような既存システムでは、塩除去率は十分であるものの、透水量が低いという問題がある。
英文要約The aim of our project is to develop high-performance forward osmosis (FO) membrane materials suitable for pressure retarded osmosis. High water flux and high salt rejection are required for the materials to improve the power conversion efficiency. Recently, polyamide reverse osmosis (RO) membranes have been substituted to FO membranes; however, this system suffers from the limited water flux. This may be come from the composite membrane structure, in which the rejected salts incorporate and stay within the polysulfone support layer. In this work, a single membrane system composed of a wholly aromatic polymer material without support layers is targeted. Wholly aromatic polymers are selected because of their high mechanical strength, facility of introducing the hydrophilic groups, and feasibility of cross-linking. High water flux is expected by a single thin membrane with hydrophilic groups dispersed in the entire region. It is essential to investigate and optimize the polymer structures including chemicals, functionality of hydrophilic groups, cross-linked network, to satisfy the requirements for FO membranes. Our group succeeded in synthesizing 14 kinds of polyamides with hydrophilic (Fn1) groups at the different functionality by solution polymerization of the corresponding diamine and carboxyl dichloride monomers. To increase the solubility of polyamides, salts are added in the polymerization media when needed. The molar ratios of hydrophilic/non-hydrophilic units are set to be 0, 5, 10, and 20%. The high inherent viscosities of the polyamides were confirmed. Additional 4 kinds of polyamides with hydrophilic (Fn2) group could also be synthesized by the polymerization of the corresponding monomers.The ultrathin polyamide membranes were prepared by coating polymer solutions onto the grass substrates, eliminating residual solvents on a hot plate, and peeling them off. As a collaboration work with Toray corp., the membrane properties of water flux and salt rejection were elucidated. No water flux was observed for polyamide membranes without hydrophilic groups, as expected. In the case of polyamide membranes with Fn1 groups (5 and 10%), a water flux of 0.04 m/d and a salt rejection of 25% were obtained. When the ratio is over 20%, the salt rejection became very low (1%). Therefore, the ratio of hydrophilic groups seems to play an important role for the membrane properties.
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