Nanotechnology in water pollution treatment
Nanotechnology in water pollution treatment
Published on: Mar 3, 2016
Transcripts - Nanotechnology in water pollution treatment
Bara’a fouad abdul ameer
While everybody talks about oil prices, water scarcity and
water pollution are two increasingly pressing problems that
could easily and quickly surpass the oil issue. Renewable
energy sources can substitute for fossil fuels – but
freshwater can't be replaced . Water is the most essential
substance for all life on earth and a precious resource for
human civilization. This makes the ability to remove toxic
contaminants from aquatic environments rapidly, efficiently,
and within reasonable costs an important technological
challenge . Nanotechnology could play an important role in
this regard . Nanotechnology is a field of applied science,
focused on the design, synthesis, characterization and
application of materials and devices on the nanoscale.
Sources of water pollution:
1- water used for domestic, commercial and other
purposes, such as schools, hotels and restaurants.
2- Water industrial uses.
4- leaking water from several sources, particularly
This water contains several solid and dissolved elements
in the form of pollutants:
stuck materials , organic materials biodegradable ,live
pathogens ,plant nutrients (nitrogen, phosphorus,
potassium ),organic materials resistant to degradation ,.
heavy metals , soluble metal salts.
Diseases caused by contaminated water:
Malaria, Cholera, Typhoid, Cystitis, Nephritis
Gastroenteritis, Viral hepatitis, Skin diseases
(hardened lesions), Goiter.
Water pollution treatment methods:
Conventional practices adopted for water purification – which
can be classified into physical, chemical and biological
methods – suffer from certain limitations such as high cost,
low adsorption capacity, generation of toxic sludge, etc. These
technologies – which include coagulation, flocculation, reverse
osmosis, membrane separation, oxidation and ozonation,
adsorption – are expensive or inadequate to remove dye.
Adsorption with activated carbons, which is a cheap and
effective method, has been demonstrated to remove dye from
wastewater. But this approach is not suitable for industrial
wastewater treatment because activated carbon can only be
used once and then it is commonly disposed of in landfills.
Moreover, removal of pathogens from treated water requires
additional processes like chlorination, ozonation, etc., which
increases the cost of treatment.
A possible solution to tackle this problem has been demonstrated
by scientists in India. They developed nanotechnology-based water
purification using nano-silica-silver composite material as
antifouling, antimicrobial and dye adsorptive material. Using this
process, pathogenic bacteria and dye present in contaminated
water can be treated simultaneously without using any chemicals,
high-temperature, pressure or electricity.
Schematic illustration of the in situ synthesis (A) of silver
nanoparticles on nano-silica support (NSAgNP) by protein
extract, (B) immobilization of protein coated silver
nanoparticles on nano-silica support by the ‘post-
Scheme of the removal of heavy metals with the
humic acid coated Fe3O4 magnetic nanoparticles.
*zero-valent iron, were directed towards the depollution of waste
water It proved to be particularly suitable for the decontamination of
halogenated organic compounds, the presence of zinc is mainly from
industrial pollution. Nanoscale zero-valent iron (nZVI) has been
investigated as a new tool for the reduction of contaminated water.
The heavy metal removal by nZVI generally involves redox,
cementation, adsorption and precipitation.
The nZVI is the core-shell structure: a single particle composed of a
dense core surrounded by a thin amorphous shell exhibiting
markedly less density than the interior core. When nanoscale iron
particles are exposed to water media, they will obtain hydroxide
groups and consequently an apparent surface stoichiometry in
proximity to FeOOH is formed.
. The FeOOH-shell could enhance the adsorption. The H+
inhibited the formation of iron (oxy)hydroxide, resulting in the
low removal extent of Zn2+ by nZVI.
Accordingly, the high removal extent of Zn2+ by nZVI might be
caused by adsorption and co-precipitation, which was proved
by the effects of DO and pH. The formation of FeOOH on the
surface of nZVI could be the main factor of Zn2+ removal
because of its high adsorption affinity for aqueous solutes.
The structure of nZVI during reaction.
Treated water uses:
Treated water can be used in several purposes, either
directly or indirectly.
In general, the re-use of treated water by various
sectors ratio are as follows:
1. Agricultural purposes 60% .
2. Industrial purposes 30% .
3. Other purposes finance groundwater 10%.