Graphene Oxide Embedded Reverse Osmosis Membrane in Both Active and - - PowerPoint PPT Presentation

Graphene Oxide Embedded Reverse Osmosis Membrane in Both Active and Support Layers

Hee-Ro Chae1, Chung-Hak Lee1,*, Pyung-Kyu Park2,

In-Chul Kim3

1 Seoul National University, Seoul , Republic of Korea 2 Yonsei University, Wonju, Gangwon-do, Republic of Korea 3 Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea

• The key properties of a RO membrane
• Water permeability, salt rejection,

anti-biofouling, chlorine resistance

• Graphene oxide (GO)

: Numerous hydrophilic & negatively charged functional groups

• Thin-film composite (TFC) membrane with GO

Introduction

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RO: reverse osmosis MPD: m-phenylenediamine

• Notation of the TFC membranes

 TFC membrane with GO embedded in Active and/or Support layers  : TFC membrane  : S-GO-TFC membrane  : A-GO-TFC membrane : AS-GO-TFC membrane

PSf PA

Notation

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AS A S AS A S

Characterization of the TFC membranes

• Most hydrophilic & negatively charged AS-GO-TFC membrane

 Numerous functional groups of GO

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TFC TFC

(n=6) (n=3)

Surface roughness of the TFC membranes

• Decrease of surface roughness with GO in active layer

Increase of surface roughness with GO in support layer

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GO Concentration in MPD solution

(n = 9)

AS A S

TFC

AS A (∝GO Conc. in Active layer)

Water permeability of the TFC membranes (n = 3)

Hydrophilicity ↑ Roughness ↑

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15.5 bar 2000 ppm NaCl, 30 min Aggregation of GO

• Higher GO-affinity of the GO-support layer

 Higher dispersity of GO in active layer

Anti-biofouling of the TFC membranes

• CLSM images of the bacteria fouled on membranes

Green: bacteria

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A-GO-TFC TFC S-GO-TFC AS-GO-TFC

CLSM: confocal laser scanning microscopy Cell attachment test at 37℃, 48 h

76 ppm GO in MPD solution

Anti-biofouling of the TFC membranes

(n = 9)

Hydrophilicity

 Hydrophobic-hydrophobic interaction ↓

Negative surface zeta potential  Net negatively charged bacteria surface  Electrostatic repulsion ↑

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AS A S TFC

After Before

Chlorine Resistance of the TFC membranes

Hydrogen bonding between GO and PA  Impeding replacement of amidic hydrogen with chlorine GO nanosheets  Barrier against chlorine for underlying PA

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(n = 3)

AS A S

Only GO in active layer was effective for chlorine resistance

TFC

In active layer 5000 ppm NaOCl, 16 h 2000 ppm NaCl, 15.5 bar 30 min

2000 ppm NaCl, 15.5 bar

30 min

This research was supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2010-0029075) and the Convergence Technology Program funded by Korea Ministry of Environment (2015001640001).

Acknowledgment

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Thank you for your attention!