Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Synthesis of Cobalt Hydroxide Nanosheets based on Sonication-induced Exfoliation for Depolymerization of Polyethylene Terephthalate

폴리에틸렌 테레프탈레이트의 해중합을 위한 초음파 박리법 기반의 코발트 수산화물 나노시트의 제조

  • Jin, Se Bin (Department of Chemical Engineering, Kangwon National University) ;
  • Son, Seon Gyu (Department of Chemical Engineering, Kangwon National University) ;
  • Jeong, Jae-Min (Department of Nanoengineering, University of California San Diego) ;
  • Choi, Bong Gill (Department of Chemical Engineering, Kangwon National University)
  • 진세빈 (강원대학교 화학공학과) ;
  • 손선규 (강원대학교 화학공학과) ;
  • 정재민 (캘리포니아대학 샌디에고 캠퍼스 나노공학과) ;
  • 최봉길 (강원대학교 화학공학과)
  • Received : 2020.10.27
  • Accepted : 2020.11.17
  • Published : 2020.12.10
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Abstract

In this work, ultrathin and two-dimensional (2D) cobalt hydroxide [Co(OH)2] nanosheets were synthesized by a sonication assisted liquid-phase exfoliation of bulk Co(OH)2. The resulting exfoliated Co(OH)2 is a hexagonal mono-layered nanosheet with a high specific surface area of 27.5 ㎡ g-1. The depolymerization of polyethylene terephthalate (PET) based on glycolysis reaction was also performed using an exfoliated Co(OH)2 catalyst. Excellent catalytic reaction performances were demonstrated; a high PET conversion and bis(2-hydroxyethyl) terephthalate (BHET) yield of both 100% using the nanosheet catalyst were achieved within a reaction time and temperature of 30 min and 200 ℃, respectively. The long-term stability of exfoliated Co(OH)2 catalysts was also demonstrated by recyclability tests of the catalyzed glycolysis reaction of PET over four cycles, showing both 100% of high PET conversion and BHET yield.

본 논문에서는 수산화코발트[Co(OH)2] 층간 소재를 초음파(sonication) 액상 박리 공정을 사용하여 얇은 2차원 나노시트(nanosheet)로 박리하였다. 상기의 Co(OH)2 촉매는 27.5 ㎡ g-1의 넓은 비표면적을 갖는 한 장의 육각 나노시트로 박리 되었다. 또한, 특성 분석 및 PET 해중합(depolymerization) 반응의 촉매로서 사용되어 고활성을 증명하였다. 해당 촉매를 사용한 PET 해중합 반응은 200 ℃에서 30 min 이내에 100%의 높은 PET전환율과 100%의 높은 BHET 수율을 보여주었다. 박리된 Co(OH)2의 재사용성을 확인하기 위해 반응 후 필터를 사용해 촉매를 회수하여 PET 해중합 반응을 진행하였다. 총 4번의 재사용 동안 100%의 PET 전환율과 100%의 BHET 수율을 보여주어 촉매의 우수한 안정성을 증명하였다.

Keywords

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