Environmental Engineering Reference
In-Depth Information
(TOc) in the permeate. Moreover, Zhu et al. [145] improved membrane antifouling, separation, and degradation of organic
pollutants using a TiO
2
-nanorod-assembled membrane coated with a mesoporous titanium (Ti)-Mn catalyst layer in the
treatment of simulated wastewater (aqueous solution of dye red-3bS and aniline) because of its high catalytic ozonation
capability.
17.4
conclUsions
environmental problems, especially water contamination, are becoming very serious and gaining significant attention world-
wide in the search for effective remediation methods to meet the continuously growing demand for clean water. Advances in
nanotechnology suggest that water quality problems can be solved. This chapter discussed the application of nanoparticles in
water remediation through adsorption, photocatalytic degradation, and disinfection. Fe
0
and nanosized metal oxides have poten-
tial as efficient nanoadsorbents of toxic materials because of their high surface area to volume ratio, high stability, and high
durability. Hybrid nanomaterials, such as Ac/chitosan/Sic-supported and bimetal nanoadsorbents, can be fabricated to enhance
the specific surface area for higher adsorption capacity and increase the removal of contaminants from water. TiO
2
and ZnO are
inexpensive, nontoxic photocatalysts with great capability in degrading contaminants in water. The deposition of metals or ions
onto photocatalysts and the immobilization of photocatalysts on a rigid support are necessary to enhance degradation efficiency.
Fe
0
, nanosized Fe
2
O
3
, and core-shell systems of nanosized photocatalysts with super paramagnetic properties are preferable for
easy reclaiming using a magnetic field. Meanwhile, TiO
2
and Ag nanoparticles showed great bactericidal effects and inactiva-
tion of various harmful microorganisms during water disinfection. The small size and high surface to volume ratio of these
nanoparticles allows them to interact closely and directly with pathogens. This chapter also reviews the development of mem-
branes incorporated with various nanoparticles including TiO
2
, SiO
2
, Al
2
O
3
, ZnO, Fe
2
O
3
, and Ag with remarkably enhanced
performances in membrane fouling and biofouling mitigation, disinfection, and photocatalytic functionalities. Various strat-
egies have been employed for the fabrication of nanoparticle-incorporated membranes. prior to the introduction of nanoparti-
cles into the membranes, modification of the nanoparticles, such as doping or surface functionalization, may be performed to
improve the functionalities and enhance the dispersion or attachment of nanoparticles. eventually, the nanoparticles are
integrated into membranes via different routes, including homogeneous dispersion, surface coating, or as ceramic membrane
precursors. The dosage of the nanoparticles should be optimized to produce more cost-competitive and better-performance
membranes in the future. Thus, the properties of nanoparticles and the ecotoxicity effects of the release of nanoparticles to the
environment need to be investigated further for drinking water applications.
acknoWledgments
The authors acknowledge USM fellowship supports from Universiti Sains Malaysia (USM) and MyphD program of the
Ministry of Higher education, Malaysia. This research was also financially supported by the Universiti Sains Malaysia research
University (rU) grant, USM Membrane cluster Grant, Fundamental of research Grant Scheme (FrGS), and postgraduate
research Grant Scheme (prGS).
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