Environmental Engineering Reference
In-Depth Information
16
Thin Film Nanocomposite Reverse
Osmosis
Membranes
Christopher J. Kurth and Bob Burk
NanoH
2
O Inc., El Segundo, California, USA
CONTENTS
16.1 Introduction ........................................................................................................................ 305
16.1.1 Mixed Matrix Membrane Development ............................................................. 306
16.1.2 Thin Film Composite Membranes ....................................................................... 306
16.2 Academic TFN Membrane Research .............................................................................. 307
16.3 Industrial TFN Development ........................................................................................... 310
16.3.1 Nanocomposite Membrane Development.......................................................... 310
16.3.1.1 Performance Data: Las Palmas III Pilot Test Example—
Increased Capacity .................................................................................. 313
16.3.1.2 Performance Data: Cayman Brac—Energy Savings .......................... 314
16.4 Conclusions ......................................................................................................................... 314
References ..................................................................................................................................... 315
16.1 Introduction
At the end of last year, 75 million m
3
of water was being desalinated each day, about two-
third of which was treated using reverse osmosis (RO) and most of the remainder using
thermal approaches (primarily multistage lash and multiple-effect distillation) [1]. Hidden
among that daily water production is 75,000 m
3
of water being treated with a new class
of RO membranes, one where improvements to the separation layer had been made by
leveraging recent developments in nanotechnology to improve its baseline performance
metrics (i.e., water and salt transport rate and surface properties relating to fouling). In
these new membranes, the traditional separation layer, irst developed in the late 1970s by
North Star Research [2] and commercialized at Filmtec [3], is replaced with a blend of an
interfacial formed polymer phase and nanomaterial, referred to as a thin ilm nanocom-
posite (TFN) RO membrane.
First conceived and reduced to practice at the University of California, Los Angeles, in
the laboratory of Eric Hoek, the initial TFN concept involved adding zeolite nanoparticles
into an interfacially formed RO membrane to give a mixed-matrix material [4]. In particu-
lar, one where the hydrophilicity of the zeolite phase could be used to minimize adhesive
interactions with potential foulants, thus improving performance stability. Zeolite Linde
Type A was selected from irst principles; its three-dimensional (3-D) interconnected pore
structure would eliminate the need to orient the nanoparticle, and its 4.9 Å pore diameter
305
