High-performance reverse osmosis CNT/polyamide nanocomposite membrane by controlled interfacial interactions.
Polyamide reverse osmosis (RO) membranes with carbon nanotubes (CNTs) are prepared by interfacial polymerization using trimesoyl chloride (TMC) solutions in n-hexane and aqueous solutions of m-phenylenediamine (MPD) containing functionalized CNTs. The functionalized CNTs are prepared by the reactions of pristine CNTs with acid mixture (sulfuric acid and nitric acid of 3:1 volume ratio) by varying amounts of acid, reaction temperature, and reaction time. CNTs prepared by an optimized reaction condition are found to be well-dispersed in the polyamide layer, which is confirmed from atomic force microscopy, scanning electron microscopy, and Raman spectroscopy studies. The polyamide RO membranes containing well-dispersed CNTs exhibit larger water flux values than polyamide membrane prepared without any CNTs, although the salt rejection values of these membranes are close. Furthermore, the durability and chemical resistance against NaCl solutions of the membranes containing CNTs are found to be improved compared with those of the membrane without CNTs. The high membrane performance (high water flux and salt rejection) and the improved stability of the polyamide membranes containing CNTs are ascribed to the hydrophobic nanochannels of CNTs and well-dispersed states in the polyamide layers formed through the interactions between CNTs and polyamide in the active layers.
School of Chemical and Biological Engineering and Institute of Chemical Process, Seoul National University , 599 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
Hee Joong
HJ
Kim
Kwonyong
K
Choi
Youngbin
Y
Baek
Dong-Gyun
DG
Kim
Jimin
J
Shim
Jeyong
J
Yoon
Jong-Chan
JC
Lee