Membrane Journal (멤브레인)

The Membrane Society of Korea (한국막학회)
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Effect of Intermittent Pressure-Assisted Forward Osmosis (I-PAFO) Operation on Colloidal Membrane Fouling and Physical Cleaning Efficiency

가압형 정삼투의 간헐적 운전이 콜로이드 파울링 및 물리세정 효율에 미치는 영향

  • Lee, Jinwoo (Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology) ;
  • Kook, Seungho (Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology) ;
  • Kim, Sung-Jo (Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology) ;
  • Kim, In S. (Global Desalination Research Center (GDRC), School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology)
  • 이진우 (광주과학기술원 지구환경공학부 글로벌 담수화 연구센터) ;
  • 국승호 (광주과학기술원 지구환경공학부 글로벌 담수화 연구센터) ;
  • 김성조 (광주과학기술원 지구환경공학부 글로벌 담수화 연구센터) ;
  • 김인수 (광주과학기술원 지구환경공학부 글로벌 담수화 연구센터)
  • Received : 2016.06.03
  • Accepted : 2016.08.08
  • Published : 2016.08.31
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Abstract

Pressure assisted forward osmosis (PAFO) is recently introduced because of its improved process efficiency to overcome drawbacks of forward osmosis (FO) such as low water flux and reverse solute diffusion. However, it is known that membrane fouling becomes deteriorated by additional hydraulic pressure applied in PAFO compared to FO. This study was performed to investigate possibility of intermittent pressure-assisted forward osmosis (I-PAFO) operation for fouling mitigation using colloidal silica particles as model foulants. FO, PAFO were operated as well to compare with. Two different solution pH conditions (pH 3, 10) were applied to see the effect of electrostatic interactions between the membrane and silica particles on fouling tendency. In the results, higher water flux was observed during pressurization and pressure relaxation periods in I-PAFO than water flux of PAFO, and FO on both pH conditions. Water flux decreased less in I-PAFO than PAFO after fouling. It resulted in higher water flux recovery in I-PAFO than PAFO after physical cleaning.

가압형 정삼투(pressure-assisted forward osmosis, PAFO) 공정은 기존의 정삼투(forward osmosis, FO) 공정의 단점인 낮은 수투과도 및 유도용질의 역확산을 극복하여 전체 공정 효율을 향상시킨다. 하지만 가압에 의한 추가적인 수리학적 압력의 작용은 파울링을 가속화 시킨다는 단점이 있다. 본 연구는 PAFO의 간헐적 운전방법인 간헐적 가압형 정삼투(Intermittent pressure-assisted forward osmosis, I-PAFO)의 파울링 저감 가능성을 평가하기 위해 수행되었다. 비교를 위해 FO 및 PAFO를 동시에 운전하여, 세 가지 운전에서의 파울링 거동을 관찰하였다. 파울링 실험을 위한 오염물질로 콜로이드 실리카 입자를 사용하였고, 분리막 및 입자의 정전기적 상호작용 에너지 변화가 파울링 거동에 미치는 영향도 확인하였다. 실험결과, I-PAFO 운전에서, 용액 pH 변화에 관계없이 가압구간, 압력완화 구간에서 각각 PAFO, FO보다 높은 수투과도를 유지하였다. 파울링 실험 후, PAFO에 비해 I-PAFO운전에서 더 적은 수투과도 감소가 관찰되었고, 이로 인해 물리세정 후 향상된 수투과도 회복률 또한 관찰되었다.

Keywords

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