WATER TREATMENT METHOD AND WATER TREATMENT SYSTEM

• Main Authors: MIURA YUKI, KUMANO ATSUO, NAKAO TAKAHITO, MATSUIDE TERUHIRO, YASUKAWA MASAHIRO
• Format: Patent
• Language: English; Japanese
• Published: 17.01.2024
• Subjects: CHEMISTRY; METALLURGY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

To further improve efficiency in a water treatment method including an osmosis treatment using a lower limit critical solution temperature (LCST) draw solute.SOLUTION: The water treatment method comprises: a forward osmosis step of bringing one surface of a semi-permeable membrane 10 into contact with a target solution including water and other components, and bringing the other surface of the semi-permeable membrane into contact with a draw solution including a draw solute reduced in solubility due to a temperature increase, and moving the water included in the target solution through the semi-permeable membrane into the draw solution; a phase separation step of separating the draw solution into a low-concentration draw solution and a high-concentration draw solution by increasing the temperature of the draw solution after the forward osmosis step; and a membrane separation step of separating the low-concentration draw solution into water and a concentrated liquid including a draw solute by using a separation membrane 20. The draw solute includes a copolymer represented by Formula (1).SELECTED DRAWING: Figure 1 【課題】下限臨界共溶温度（ＬＣＳＴ）型ドロー溶質を用いる正浸透処理を含む水処理方法において、更なる効率化を図ること。【解決手段】半透膜１０の一方の面を、水と水以外の成分を含む対象溶液に接触させると共に、半透膜の他方の面を、温度上昇により溶解度が低下するドロー溶質を含むドロー溶液に接触させることで、対象溶液中に含まれる水を、半透膜を通してドロー溶液に移動させる、正浸透工程と、正浸透工程の後に、ドロー溶液の温度を上昇させることで、ドロー溶液を低濃度ドロー溶液と高濃度ドロー溶液とに分離する、相分離工程と、分離膜２０を用いて、低濃度ドロー溶液を水とドロー溶質を含む濃縮液とに分離する、膜分離工程と、を含み、ドロー溶質は、式（１）で表される共重合体を含む、水処理方法。TIFF2024005365000008.tif7125【選択図】図１