water treatment using nanotechnology enhanced membranes
TRANSCRIPT
Water Treatment using Nanotechnology Enhanced
Membranes
Mohammed Al-Abri
Nanotechnology Research Center
Petroleum & Chemical Engineering DepartmentSultan Qaboos University
Overview
Nanotechnology definition and applications
Membrane definition and classification
Membrane fouling
Membrane modification
Applications in wastewater treatment
Conclusions & Recommendations
Name: Nanotechnology
Norio Taniguchi, 1974
Popularized by Eric Drexler, 1986-87
Nanotechnology is the understanding and control
of matter at dimensions of roughly 1 – 100 nm
There’s plenty of room at the bottom
Richard P. Feynman, 1959
“to manipulate matter on an atomic scale”
Nanotechnology
Plastics
Ceramics
Oil Industry
Medications
Manufacturing
Transportation
Textiles
Metals
Electronics
Energy
Sensors
DiseaseTreatment
OrganGrowth
Weapons
Waste Surgery
Applications
5
http://www.nano.gov/nanotech-101/what/nano-size
A sheet of paper is about 100,000 nm
thick
Size and scaling
One nanometer is about as long as your
fingernail grows in one second
Scaling (Downsizing)
If the diameter of a marble was one nanometer, then
diameter of the Earth would be about one meter
Why nanoscale?At nanoscale, the material properties (physical, chemical and electronic)
change
“Melting point, optical, electrical conductivity, chemical reactivity and so
on…”
90 nm 50-60 nm 10-20 nm
“Become magnetic at 3 nm and shows high activity in catalytic CO
oxidation reactions”
Surface area increment Greater amount of the material comes into contact with
surrounding materials and increases reactivity
8
Total SA 6cm2
1cm cube
1mm
Total SA 60cm2
1nm
Total SA 60,000,000 cm2
Dramatically increased in surface area (SA)
Bulk to Nanoscale
More atoms to contact the surface !
9
Lotus leaf
Grass
Rose petal
Feather
Learn from NATURE
Butterfly wing
Banana leaf
Gecko
Morpho
Introduction to Nanoscience, CRC press
Membrane definition and classification
feed permeate
1 nm 10 nm 100 nm 1 µm
Microfiltration
Ultrafiltration
Nanofiltration
Reverse OsmosisNa+
Cl-
Membrane fabrication
Fabrication methods
Interfacial polymerisation
Phase inversion Track-etching Electrospinning
Membrane casting
Gelation,phaseinversion
NPs- polymer dope solution preparation
Thin film composites (TFC)
12
Fouling types
• Colloidal fouling
• Organic fouling (Protein, Humicsubstances, oil, NOM)
• Scaling (CaSO4, MgSO4)
• Biofouling (bacteria and Fungi)
Fouling forms
• Adsorption
• Pore blocking
• Gel/cake formation
• Deposition
Fouling consequences
• Blocking of membrane pores
• Permeate flux decreases
• Production efficiency decreases
• Operation time increases
Fouling prevention
• Pre-treatment of feed solution
• Membrane modification
• Physical cleaning
• Chemical cleaning
• Self-cleaning process
• Optimization of operating parameters
Membrane fouling
Membrane modification
Physical
• Plasma treatment
• Create new functional groups at the surface
• Crosslinking of polymer chains
Chemical/ Biochemical
• Addition of functional groups
• Enzyme attachments
• Antibiotics attachment
Nanomaterials
• Magnetic material
• HMO & α-Fe2O3
• Metal & metal oxides
• Ag, ZnO, TiO2,..
• Carbon material
• Carbon nanotubes (CNT) & grapheneoxide (GO)
14Functionalization Methods for Membrane Surfaces. In Surface Engineering of Polymer Membranes, Springer Berlin Heidelberg: 2009; pp 64-79Victor, K., Reduction of Membrane Fouling by Polymer Surface Modification. In Membrane Modification, CRC Press: 2012; pp 41-76
Mechanical strength: Heat-treated nanofibrous cannot slide freely.
TEM: annealing stage minimized the NPs aggregation
PES electrospun membraneswith hydrous MnO2
Permeate flux and oil rejection measurements (5000 ppm oil)
UV lamp A
(365 nm) mode
Methylene blue (MB)
Humic acid (HA)
Photocatalysis tests
Nanofibers Polyetherimide Membranes Enhanced with Titanium Dioxide For Wastewater Treatment
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200
Ct/
C0
Wavelength (cm-1)
MB
Control
PEI
TiO2/PEI
Degradation of > 77% in HA concentration
Degradation of HA and MB dye
0
0.2
0.4
0.6
0.8
1
1.2
0 50 100 150 200
Ct/
C0
Time (hr)
HA
UV
without UV
Degradation of > 85% in MB concentration
PES modification with functionalized carbon nanotube
Membrane casting
Gelation,phase inversion
Nps- polymer dope solution preparation
NPs-PES membrane fabrication
PES modification with functionalized carbon nanotubes
• Functionalized CNT inhibit bacterial growth
• PES-CNT-2 highest inhibition ~ 99%0.0E+00
2.0E+08
4.0E+08
6.0E+08
8.0E+08
CF
U/m
L
Performance of PES-CNT membranes
0102030405060708090
100
PW
F (
L.m
-2.h
r-1)
0
20
40
60
80
100
0
20
40
60
80
100
% F
lux r
ecover
y
%B
SA
rej
ecti
on
Conclusions & Recommendations
Membranes gained traction in water treatment
Membrane fouling is a serious issue
Membranes’ modification using nanomaterials enhances membrane performance
Nanotechnology can be used to fabricate specifically tailored membranes for specific water treatment
Toxicity and long-term stability studies are needed
Credits and Acknowledgements