1) The document discusses using graphene oxide nanoplatelets to coat hollow fiber membranes used in membrane bioreactors to treat water. 2) Experiments showed that coating membranes with about two grams of graphene oxide improved water flux the most by reducing fouling. Further exposing the graphene oxide coating to UV light improved water flux even more. 3) Testing the coated membranes with various foulants like proteins and salts found in wastewater, as well as sewage water, demonstrated that the graphene oxide coatings decreased the loss of water flux over time and reduced the pressure needed for filtration compared to uncoated membranes.

1. Graphene Oxide Nanoplatelets Composite Membranes
for Membrane Bioreactor Treatment
Emily Jeng, Mahdi Fathizadeh, Zhuonan Song, Weiwei Xu, Lei Wang, Miao Yu
Department of Chemical Engineering, University of South Carolina
Background
Water pollution, especially from industrial processes, is a
growing environmental concern. Currently, membrane
bioreactors (MBRs), which utilize membranes for water
filtration, are being investigated as a very promising method of
separating water from its contaminants. However, membrane
fouling causes severe problems, such as decreasing the
lifespan of the membrane and adding to costs of water
filtration. Graphene oxide has been considered as an effective
coating material on commercial microfiltration membranes to
alleviate the fouling problem.
Materials/Experiments
• Different amounts of graphene oxide were applied to
hollow fiber membranes to find the optimum coating
thickness that gives the most ideal membrane
performance
– Some membranes were also coated with
graphene oxide exposed to UV light
• Membranes were subjected to:
– pure water
– solutions with typical foulants found in
membranes:
• Silicon dioxide
• Bovine serum albumin
• Sodium alginate
– sewage water
References
1. J. Lee, H.-R. Chae, Y.J. Won, K. Lee, C.-H. Lee, H. H. Lee, I.-C. Kim, and J.-M. Lee, Journal of Membrane Science, 2013, 448, 223-230
2. H. Li, Y. Huang, Y. Mao, W. L. Xu, H. J. Ploehn, and M. Yu, Chem. Commun., 2014, 50, 9849
3. J. Huang, Z. Wang, J. Zhang, X. Zhang, J. Ma, and Z. Wu, Scientific Reports, 2015, 5, 9268
Acknowledgments to the following:
University of South Carolina, Department of Chemical Engineering:
-Dr. Jochen Lauterbach and Dr. Chris Williams, REU Program Directors
-Center of Catalysis for Renewable Fuels
-NSF-EEC-1358931
Conclusion
• water flux decreased gradually when the membranes were tested in solutions involving
foulants
• applying about two grams of graphene oxide to the membranes had the greatest water flux
• Coating a membrane with graphene oxide exposed to UV light increased water flux even
more
• The better the membrane, the less pressure was needed for water permeation through the
membrane
Hollow fiber membranes, cylindrical fibers with pores for the
purpose of filtration
A vacuum pump
was used on the
permeate side of
the membrane
to provide the
driving force for
water
permeation
0
50
100
150
200
250
300
0 0.5 1 1.5 2 2.5 3
Flux[L/(m2.hr.bar)]
GO content (gr)
Pure Water Flux vs. GO content
The sludge was prepared
from the City's
Metropolitan
Wastewater Treatment
Plant. The MBR setup
was fixed for 20 L/m2.hr.
The required pressure
(transmembrane
pressure, TMP) was
measured with time.
30
35
40
45
50
55
60
65
0 50 100 150 200 250
Waterflux(L/m2.hr.bar)
time (min)
Comparison of Water Fluxes with
Different Amounts of GO applied
"pure" 0.5 gr Go 1 gr GO
2 gr Go 3 gr GO
30
40
50
60
70
80
90
100
0 50 100 150 200
WaterFlux(L/bar*hr*m2)
Time (min)
Comparison of Water Fluxes for
Amount of UV Treatment
"pure"
2 gr Go
30 min UV
60 min UV
Graphene oxide, hydrophilic nano-platelets that
are only one nanometer-thick and have flexible
structure
0
20
40
60
80
100
120
140
0 50 100 150 200 250
WaterFlux(L/bar*hr*m2)
Time (min)
Comparison of Water Flux
Between Pure Water and Foulants
Pure Water
Bovine Serum Albumin
SiO2
Sodium Alginate
Uncoated Coated with 3 gr GO
Coated with 2 gr GO Coated with 2 gr GO, 1 hr UV
SEM FTIR
Epoxy
group
Acidic group
(O-H)
Results
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 1000 2000 3000 4000 5000 6000
TMP(bar)
Time (min)
Transmembrane Pressure Vs. Time
Uncoated membarne
coated membrane with 2 gr GO and 1
hr UV