Pervaporation Separation of fluoroethanol/water Mixtures through Crosslinked Poly(vinyl alcohol) Composite Membranes

가교된 폴리비닐알콜 복합막을 이용한 불화에탄올/물 혼합용액의 투과증발분리 특성

  • 이수복 (한국화학연구원 계면재료공정연구실) ;
  • 안상만 (한국화학연구원 계면재료공정연구실, 충남대학교 화학공학) ;
  • 장봉준 (한국화학연구원 계면재료공정연구) ;
  • 김정훈 (한국화학연구원 계면재료공정연구) ;
  • 이용택 (충남대학교 화학공학과)
  • Published : 2004.06.01

Abstract

As a preliminary study for esterification membrane reactor used to produce 2,2,2-trifluoroethylmetacrylate (TFEMA), Pervaporation behaviors with crosslinked Poly(vinyl alcohol) composite membranes were investigated for aqueous TFEA (2,2,2-trifluoroethanol) feed solutions. In this study, crosslinked PVA composite membranes were prepared by reacting PVA with glutaraldehyde (CA)/acid catalyst onto porous polyethersulfone (PES) supports. SEH images (scanning electron microscopy) showed the thicknesses of selective coating layer was about 2-3 ${\mu}{\textrm}{m}$. The swelling tests showed the dogree of crosslinking decreased as content of the crosslinking agent, GA, increased. Total permeation flux decreased while separation factor increased as the CA content increased. As operating temperature increased, total permeation flux remarkably increased in the range of 85-95 wt% TFEA aqueous solutions. Interestingly, however, separation factor decreased in 85-90 wt% with operating temperature, while that increased in 95 wt%. In case of 90 wt% TFEA concentration and operating temperature 8$0^{\circ}C$, the PVA composite membrane crosslinked with 0.1 mol GA per PVA repeating unit showed high permeation flux of 1.5 kg/$m^2$hr and separation factor of 320. These results confirmed the applicability of the PVA composite membranes for the esterification membrane reactor of TFEMA.

본 연구는 에스텔화 막반응공정에 의한 2,2,2-trifluoroethyl metacrylate (TFEMA)의 생산을 위한 선행연구로, 가교된 poly(vinyl alcohol) 복합막을 이용하여 TFEA (2,2,2-trifluoroethanol)/water 혼합용액을 대상으로 투과증발 특성을 연구하였다 복합막은 다공성 polyethersulfone (PES) 지지체 위에 PVA와 glutaraldehyde (GA)를 같이 녹인 수용액을 코팅한 후 산 촉매 하에서 열가교시킴으로써 제조하였다. SEM (scanning electron microscopy)을 통하여 선택층의 두께는 2-3 $\mu\textrm{m}$로 확인되었고, 제조한 PVA 코팅층의 수평윤도는 가교제의 농도가 증가함에 따라 감소하는 경향을 보였다. 투과증발 실험결과 가교제의 농도가 증가할수록, 투과도는 감소하고 TFEA/water의 선택도는 증가하는 경향을 보였다. 그리고 85-95wt%의 TFEA 혼합용액의 전범위에서 운전온도가 증가할수록 투과도는 증가하였지만, 선택도는 90 wt% TFEA 농도 이하에서는 감소하는 경향을 보인 반면, 95 wt%에서는 증가하는 흥미로운 경향을 보였다. 0.1 moi GA로 가교된 PVA 복합막은 운전온도 8$0^{\circ}C$, 90 wt% TFEA 농도에서 1.5 kg/$m^2$hr의 매우 높은 투과도와 320의 선택도를 보였으며, 따라서 TFEA의 에스텔화 막반응공정에 적용 가능성을 보여주었다.

Keywords

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