A Novel Application of PolyHIPE Membrane as Supported Membrane for Metal Ions Separation

• Main Author: LE THI TUYET MAI
• Other Authors: Jyh-Herng Chen
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/ujg9t8

博士 === 國立臺北科技大學 === 資源工程研究所 === 107 === One of the major environmental risks is posed by heavy metals, which are toxic, persistent and unable to be degraded chemically or biologically in the environment. During the past years, membranes have been greatly improved with significantly enhanced performance and commercial markets have been spreading very rapidly throughout the world. In this thesis, a highly porous PolyHIPE membrane consisted of poly(styrene-co-2-ethylhexylacrylate) is proposed as supported liquid membrane. The PolyHIPE membrane with characteristic pore structure of open voids (10-15 µm) interconnected with many smaller windows throats (less than 1.5 µm) can be used for supported liquid membrane. With this advantageous pore structure, PolyHIPE present a potential membrane support for carrier facilitated transport membrane. The Aliquat 336-immobilized PolyHIPE membrane is demonstrated for wastewater treatment by Cr (VI) separation which is widely used in many industries (electroplating, leather, dyes, and textile) at low concentration (0.001M). Impregnation of extractant is one of the major factors for the success preparation of supported liquid membrane. By solvent-nonsolvent method, the amount of immobilized Aliquat 336 in the porous PolyHIPE membrane is as high as 2.77±0.01 g/g of PolyHIPE. The kinetic study of Cr (VI) separation shows that high initial flux and stripping flux (Jfo = 15.01 (µmol/m2s), Jsmax = 6.15 (µmol/m2s)) can be achieved by Aliquat 336/PolyHIPE membrane. The effective diffusivity of Cr (VI) is as high as 1.75×10-11 m2 s-1. In addition, this study investigated that the mixtures of co-extractants can give rise to synergistic effects and better selectivity of metal extraction and separation in solvent extraction processes. By solvent-nonsolvent method, the amount of D2EHPA/TBP co-extractants immobilized into PolyHIPE membrane was proposed for Co (II)/Mn (II) separation which are important metals in high-technology industries involving batteries, alloys, magnetic materials, and catalysts. The pore structure of PolyHIPE membrane and the presence of TBP enhance the stability of immobilized co-extractants in the membrane. After the removal of Mn (II) (>97.1%), the high purity of Co (II) can be recovered from the feeding phase, while the high purity of Mn (II) can be recovered in the stripping phases. The stability and reusability study shows that the membrane can maintain high performance recovery efficiency (about 97%) even after 15 consecutive cycles of separation operation. PolyHIPE with high porosity and advantageous pore structure present a potential membrane support for carrier facilitated transport membrane.