Introduction - Nanotechnologies for Water Environment Applications - page 2

environmental applications as an important area and started to bring together
information generated on research and applications of nanotechnology in water
environments. This topic is the result of these efforts.

As an introduction to this topic, we would like to introduce a broader picture of
nanotechnology with an emphasis on its applications and implications in water
environments. This chapter starts with a brief overview of the nanotechnology realm,
followed by an introduction of major applications of nanotechnologies in water
environments. To round out the discussion, implications of nanotechnologies and
research needs are described.

1.2 Past, Present, and Future

Nanotechnology presents opportunities to create new and better products. The
realm of nanoscience, however, is not new. Chemists have been doing nanoscience for
centuries; the medieval glass workers and Einstein (calculated the size of a sugar
molecular as 1 nm) can be viewed as earlier nanoscientists. Nevertheless, modern vision
of nanoscience starts in 1959 when Richard Feynman gave his speech “There's Plenty of
Room at the Bottom,” outlining the essentials of a nanotech capability and the prospects
for atomic engineering. The word “nanotechnology” was used by Nario Taniguchi in
1974 to describe machining with tolerances of < 1 m. In 1985, Richard Smalley,
together with Robert Curl and Sir Harold Kroto, discovered C 60 , the
buckminsterfullerene (also known as the buckyball), symbolizing the dawn of “The
Coming Era of Nanotechnology.”

Currently, nanotechnology is changing our world everywhere every day. In
general, there are four major steps in the NMs pipeline: fabrication and functionlization
of NMs, incorporation into nanocomposites and final application. Overall, the roadmap
of NMs involves four phases: basic research and development (R&D), applied R&D,
production R&D (first applications), and mass production and incremental research
(mass production). In many cases, these steps (or even phases) may combine or tangle
together in order to produce a matrix NMs (Willems & van den Wildenberg, 2005). The
remaining section describes briefly the pipeline and different phases involved in
nanotechnology applications.

Fabrication of NMs can be achieved via (a) solid state methods (e.g., grinding,
milling, mechanical alloying techniques), (b) vapor methods (e.g., physical vapor
deposition, PVD; chemical vapor deposition, CVD; vacuum evaporation on running
liquids, VERL), (c) liquid-phase chemical synthesis methods (e.g., sol-gel approach,
colloidal chemistry), (d) gas-phase chemical synthesis methods (flame pyrolysis, electro-
explosion, laser ablation, plasma synthesis techniques), and (e) many other methods