Modification of thin-film polyamide membrane with multi-walled carbon nanotubes by interfacial polymerization
Modification of thin-film polyamide membrane with multi-walled carbon nanotubes by interfacial polymerization
Abdullah S. Al-Hobaib 0 1 2
Kh. M. Al-Sheetan 0 1 2
Mohammed Rafi Shaik 0 1 2
M. S. Al-Suhybani 0 1 2
0 Department of Chemistry, College of Sciences, King Saud University (KSU) , P.O. Box 2455, Riyadh 11451 , Saudi Arabia
1 Nuclear Science Research Institute, King Abdulaziz City for Science and Technology (KACST) , P.O. Box 6086, Riyadh 11442 , Saudi Arabia
2 & Mohammed Rafi Shaik
Polyamide thin-film composite (TFC) was fabricated on polysulfone (PS-20) base by interfacial polymerization of aqueous m-phenylenediamine (MPD) solution and 1,3,5-benzenetricarbonyl trichloride (TMC) in hexane organic solution. Multi-wall carbon nanotubes (MWCNT) were carboxylated by heating MWCNT powder in a mixture of HNO3 and H2SO4 (1:3 v/v) at 70 C under constant sonication for different periods. Polyamide nanocomposites were prepared by incorporating MWCNT and the carboxylated MWCNT (MWCNT-COOH) at different concentrations (0.001-0.009 wt%). The developed composites were analyzed by Fourier transform infrared spectroscopy-attenuated total reflection, scanning electron microscopy, transmission electron microscopy, contact angle measurement, determination of salt rejection and water permeate flux capabilities. The surface morphological studies displayed that the amalgamation of MWCNT considerably changed the surface properties of modified membranes. The surface hydrophilicity was increased as observed in the enhancement in water flux and pure water permeance, due to the presence of hydrophilic nanotubes. Salt rejection was obtained between 94 and 99% and varied water flux values for TFC-reference membrane, pristineMWCNT in MPD, pristine-MWCNT in TMC and MWCNT-COOH in MPD were 20.5, 38, 40 and 43 L/m2h. The water flux and salt rejection performances revealed that the MWCNT-COOH membrane was superior membrane as compared to the other prepared membranes.
Polymerization; Phenylenediamine; Membrane; Carbon nanotube; Desalination
Introduction
Desalination of wastewater or sea water to generate
freshwater is acknowledged to be one of the major
significant concerns in the science and conservational
engineering fields. The deficiency of freshwater can be due to
the quick increase in world population and environmental
contamination
(Al-Sheetan et al. 2015; Potts et al. 1981;
Pendergast and Hoek 2011; Kang and Cao 2012; Greenlee
et al. 2009)
. There are several categories of membranes, for
instance reverse osmosis (RO), nanofiltration, ultrafiltration
and microfiltration membranes. In these membrane
methods, RO is the most extensively applied process for water
desalination
(Lee et al. 2011; Elimelech and Phillip 2011;
Nataraj et al. 2006)
. In short, the RO membrane method is
recognized as the most effective to eliminate small-sized
ions in sea water. Presently, polyamide membranes are
comprehensively used in the RO methods, because they
provide better salt rejection and have high water
permeation flux.
There have been several efforts to develop the
performance and properties of the RO membrane, such as
antifouling property, water permeability, chemical stability
and salt rejection
(Kang and Cao 2012; Lee et al. 2011; Li
and Wang 2010; Fathizadeh et al. 2011; Zhou et al. 2009)
.
Presently, nanocomposite polyamide membranes
comprising nanomaterials such as metal oxide nanoparticles
including silver, titanium, zinc, zeolite and carbon
nanotube (CNT) have been established to improve the
performances and properties of these membranes
(Cong et al.
2007; Shawky et al. 2011; Lee et al. 2007, 2008; Lind et al.
2009; Kim et al. 2012)
. Among nanomaterials, carbon
nanotube (CNT) that was first identified by Iijima Sumio in
1991 displays outstanding electrical, optical and
mechanical properties and has been utilized in wide areas of
engineering and chemistry fields. Particularly, CNT has
been thoroughly studied for use in the areas of fuel cell,
sensor, electrode of lithium battery, nano-probe, drug
delivery, gas separation, display, energy storage, ion
exchange and filters
(Ajayan 1999; Nikolaev et al. 1999;
Couvreur et al. 2002; Cicero et al. 2008; Gusev and Guseva
2007; Coleman et al. 2006)
.
CNTs have been considered for water treatment method
because of their exceptional properties. The incorporation
of carbon nanotube in membranes has been known to have
high liquid or gas permeability and mechanical and
chemical stability
(Shi et al. 2013)
. Improved separation
performances were achieved by employing those CNTs as
inclusions to polymers
(Qiu et al. 2009; Kim and Van der
Bruggen 2010; Sahoo et al. 2010)
. CNTs are tubular in
shape and offer the fast transport way to pass water
molecules. Water molecules can go into the inside of CNT
by capillary force because of the nanosized capillary
structure of CNT and they can pass through the
hydrophobic inner side of CNT
(Iijima 1991; Hummer
et al. 2001)
. These polymeric (...truncated)