Environmental Engineering Reference
In-Depth Information
17
Water remediation Using nanoparticle
and nanocomposite membranes
Kian Fei Yee, Qian Wen Yeang, Yit Thai Ong, Vel Murugan Vadivelu, and Soon Huat Tan
School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Pulau Pinang, Malaysia
17.1
introdUction
Globally, the demand for clean water has increased due to the increasing world population. The rapid development of the
industrial and agricultural sectors that consume large amounts of hazardous chemicals, toxic materials, and pesticides has
resulted in the contamination of groundwater and the generation of contaminated wastewater [1]. This phenomenon further
increased the demand for clean water, particularly drinking water. The World Health Organization (WHO) has set a guideline
on the allowable concentration of chemicals in drinking water, without causing health issues [2]. Some of the major chemicals
that often exist in contaminated water have been selected, and the guideline values are given in Table 17.1. Thus, there is an
urgent need for new technologies that reduce the contaminants in water.
Advances in nanotechnology suggest that water quality problems could be solved through the utilization of nanomaterials in
water remediation because nanomaterials possess properties suitable for water remediation, such as large surface area, high
sorbent capacities, and the ability to be functionalized to enhance affinity and selectivity [3]. There are several methods to
remove contaminants from water using nanoparticles, including adsorption, photocatalytic degradation, and disinfection. Such
methods can be performed using the following: nanoadsorbents, such as nanoscale iron particles (Fe
0
) and nanosized metal
oxides; nanophotocatalysts, such as titanium dioxide (TiO
2
) and zinc oxide (ZnO) nanoparticles; and disinfection agents, such
as biogenic silver nanoparticles (bio-Ag
0
). However, modifications are still required to improve the efficiency of nanoparticles
in the remediation of contaminants [4-7]. These modifications will eventually lead to the development of new and novel nano-
materials with specific properties and functions, including bimetal nanoadsorbents, rigidly supported nanoadsorbents, and
core-shell systems of nanosized photocatalysts. Meanwhile, nanoparticles with magnetic properties have always been preferred
in water remediation, for the easy separation of contaminant-loaded nanoparticles from treated water, by applying a magnetic
field. In the water disinfection process, metallic Ag and TiO
2
nanoparticles are the frequently used disinfection agents because
of their bactericidal effects and the ability to inactivate a wide range of harmful microorganisms.
Membrane technologies have also been gaining significant interest in the field of water and wastewater treatment because of
their efficiency in contaminant removal. Due to the recent advances in nanotechnology, various nanoparticles have been incor-
porated into membranes to produce synergistic effects on the treatment processes. Astounding effects of the introduction of
nanoparticles for the development of membranes for the said purposes have been widely reported, including fouling mitigation,
improved permeation quality, and flux enhancement. TiO
2
, Ag, aluminum oxide (Al
2
O
3
), and silicon dioxide (SiO
2
) nanoparti-
cles are among the many nanomaterials being employed. This chapter focuses on the role of various nanoparticles in water
remediation, as well as the role of nanomaterials in membrane technology for water and wastewater treatment processes.
