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 Chae 1 , Chung-Hak Lee 1,* , Pyung-Kyu Park 2 , In-Chul Kim 3 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

Introduction • 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 RO: reverse osmosis MPD: m-phenylenediamine 2

Notation • Notation of the TFC membranes  TFC membrane with GO embedded in A ctive and/or S upport layers  : TFC membrane PA PSf  : S -GO-TFC membrane GO  : A -GO-TFC membrane GO : AS -GO-TFC membrane GO GO 3

Characterization of the TFC membranes • Most hydrophilic & negatively charged AS-GO-TFC membrane  Numerous functional groups of GO TFC S A AS TFC S A AS (n=3) (n=6) 4

Surface roughness of the TFC membranes • Decrease of surface roughness with GO in active layer Increase of surface roughness with GO in support layer (n = 9) TFC S A AS A AS GO Concentration in MPD solution ( ∝ GO Conc. in Active layer) 5

Water permeability of the TFC membranes (n = 3) - Higher GO- affinity of the GO -support layer  Higher dispersity of GO in active layer Aggregation of GO Hydrophilicity ↑ Roughness ↑ 15.5 bar 2000 ppm NaCl, 30 min 6

Anti-biofouling of the TFC membranes • CLSM images of the bacteria fouled on membranes S -GO-TFC TFC A -GO-TFC AS -GO-TFC 76 ppm GO in MPD solution Green: bacteria CLSM: confocal laser scanning microscopy Cell attachment test at 37 ℃ , 48 h 7

Anti-biofouling of the TFC membranes (n = 9) Hydrophilicity  Hydrophobic-hydrophobic interaction ↓ Negative surface zeta potential  Net negatively charged bacteria surface  Electrostatic repulsion ↑ TFC S A AS 8

Chlorine Resistance of the TFC membranes (n = 3) 2000 ppm NaCl, 15.5 bar 2000 ppm NaCl, 15.5 bar 5000 ppm NaOCl, 16 h 1 30 min 30 min 1 Only GO in active layer was effective for chlorine resistance Before Hydrogen bonding between GO and PA  Impeding replacement of After amidic hydrogen with chlorine GO nanosheets  Barrier against chlorine for underlying PA In active layer TFC S A AS 0 9

Acknowledgment 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). 10

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