Environmentally friendly separation and concentration method focusing water function

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K12242
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 64030:Environmental materials and recycle technology-related
• Research Institution: Kanagawa University
• Principal Investigator: Nishimoto Yuko 神奈川大学, 理学部, 教授 (70241114)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 環境水 / 凍結融解 / 分離濃縮 / 共融混合物

Outline of Final Research Achievements

We constructed the system that separates and concentrates trace elements and components in environmental water such as river water, seawater, and sewage by freezing and melting using a eutectic mixture of salt and water.
Alkaline halides and nitrates, which are always contained in environmental water, form a eutectic of salt and water at low temperatures. After the ice is formed, it is held in a temperature range where only the eutectic of salt and water has melted, concentrating the minor components in the water in the eutectic mixture. Boron (boric acid) and phosphorus (phosphoric acid) are taken up as rare elements present in river water and hot spring water, and neutral amino acids and ATP are taken up as organic components. The optimum salt concentration studied in the model system was NaCl 5 mM. It was found that the environmental water can be efficiently concentrated by diluting the salt concentration to 5 mM.

Free Research Field

分析化学・環境分析

Academic Significance and Societal Importance of the Research Achievements

２つの意義があると考える。
１つめは環境水から稀少成分を有害な試薬を用いずに濃縮分離するシステムが構築できた点。２つめは環境中の微小微量成分の濃度変化に対する知見を与える点である。自然界においては河川水の冬期における凍結、春期における融解が起こる地域も少なくない。さらに近年の温暖化により、海水では氷山の融解が起こっている。これら自然界における微量元素や成分の融解時の濃度変化は重要な知見である。