Page 637 - Polymer-based Nanocomposites for Energy and Environmental Applications

588 Polymer-based Nanocomposites for Energy and Environmental Applications

Fig. 21.16 Mechanism of photocatalysis.

Hydroxyl and allied radicals are strong oxidizing agents, and these can degrade any
organic contaminant to smaller products, which are almost harmless or less harmful.
It is reported that photocatalytic reactions are triggered when a photocatalyst such as
TiO 2 absorbs a photon that has a higher energy than its band gap (Fig. 21.16) [73].
Polypyrrole (PPy)-TiO 2 composite, polyethylene-TiO 2 , and polyvinylchloride
(PVC)-TiO 2 composites were found to enhance degradation reactions more effec-
tively than a suspension of TiO 2 NPs [74]. Efficient adsorption and photodegradation
of textile dyes orange II and methyl orange under UV irradiation using polyaniline
(PAni) and PAni-TiO 2 composite nanotubes as photocatalyst have been reported [74].

21.8 Efficacy of polymer nanocomposites compared
to conventional methods

So far, the conventional water treatment technologies have been ineffective for pro-
viding adequate safe water. However, multifunctional and highly efficient processes
based on nanotechnology are providing affordable solutions to water treatments [75].
Nanomaterials are contributing to the development of more efficient treatment pro-
cesses among the advanced water systems. In this context, polymer nanocomposites
have been intriguing. Physical, thermal, and other unique properties of polymer
nanocomposites can be tuned, and the advent of nanotechnology be further effectively
applied for various technologies. The polymer nanocomposites possess superior prop-
erties to conventional microscale composites and can be synthesized by simple and
inexpensive techniques. Polymer nanocomposites have proved themselves to be an
ideal for flexibly adjustable water treatment systems.
Polymer nanocomposites comprising nanoengineered materials are in most
instances compatible with existing treatment technologies and can be integrated sim-
ply in conventional modules. One of the most important advantages of
nanocomposites when compared with conventional water technologies is their ability
to integrate various properties. This results in multifunctional systems such as
nanocomposite membranes that enable both particle retention and elimination of