25.4 Nanotechnologies in Waste Reduction and Management

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such as adsorption, membrane filtration, separation, and photocatalysis. Natural

products like activated carbons, kaolins, peat, clays, zeolite, aluminosilicates have

high adsorption power. Some nanoparticles destroy the contaminants (oxidation in

presence of nanocatalysts), separation and isolation of contaminants (nanofiltra-

tion). Metallic nanoparticles with zero valency, nanocomposites, carbon nanotubes

are finding great promise in wastewater remediation. Carbon-based nanomaterials,

e.g. multiwalled carbon nanotubes that have much higher metal-ion sorption power

than activated charcoal or cylindrical membranes with tiny pores capable enough

to filter out microorganisms, zero valent metallic nanoparticles of iron, aluminum,

nickel, and zinc are finding great potentials in wastewater pollution prevention

and treatment [32–35]. Membrane filtration plays an important role in water

purification process. Nanofiltration is a high-pressure membrane treatment process

unlike reverse osmosis it requires much lower pressure drive (7–14 bar) and thus is

an energy efficient procedure. Wastewater after nanofiltration is found to be suitable

for reuse, and it found to meet the stringent quality requirements. A wide range

of membranes, viz. nanostructured ceramic membrane, organic–inorganic mem-

brane, biologically inspired membranes, thin film composite membrane, carbon

nanotube-polymer, zeolite-polymer, aquaporin-polymer are used for the purpose of

nanofiltration [32]. Metallic nanoparticles are good catalysts in oxidative reactions;

these nanocatalysts can be used for oxidation of organic–inorganic pollutants in

wastewater by advanced oxidation processes. Photocatalytic reactions absorb the

photon and create highly reactive radicals that can react with the molecules of

pollutants and break them down. Though practical application of photocatalysis is

challenged by proper optimization of catalysts and efficient separation of nanocat-

alysts but as the method utilizes the renewable solar energy and being an open

air process, calls for the development of efficient and costeffective procedures for

wastewater treatment [32, 34]. Remediation of wastewater using nanotechnology is

an important strategy in waste management. The nanostructures or nanoparticles,

specifically used for the purpose of remediation of contaminated ground water

must be highly reactive toward the contaminants, have an appropriate life span

with proper mobility in porous materials and negligible harmful effects. Nano scale

zero valent iron (nZVI) finds potential application in remediation of wastewater.

The popularity of nZVI in waste management is owing to its high reactivity toward

the contaminants, eco-friendly nature, low production cost, capability of surface

modifications, and selective specificity toward certain contaminants and their stabi-

lization [32, 34]. For the purpose of solid waste disposal, it is also necessary to assess

the “life cycle” of the products. But proper sorting and recycling may be expensive

and tedious. Nanotechnology offers the solutions, where nanomaterials can be

used as “nanotags.” Such barcodes are easily detectable by infrared spectroscopy

or Raman fluorescence and will help in easy tracking of products throughout their

lifecycle [1].

Nanobiotechnology exploits the techniques of nanotechnology to study the biolog-

ical systems, whereas bionanotechnology utilizes natural or biomimetic systems to

fabricate classic nanostructures with versatile applications. The outcomes of bionan-

otechnology are the self-assembled nanostructures, biomolecular nanostructures,