Nanotechnology can be used in various ways for water purification and oil spill removal. For water purification, nanomaterials like carbon nanotubes, nanofibrous alumina filters, and nanocellulose can be used in membranes and filters to remove contaminants like bacteria, viruses, and chemicals due to their large surface area. For oil spill removal, magnetic nanoparticles, photocatalytic nanoparticles, and nano dispersants can break down or absorb oil. While nanotechnology shows promise for these applications, further research is needed to address limitations and health and environmental concerns regarding nanomaterials.

1. Applications of Nanotechnology in
Water purification
and
Oil spill removal
Presentation by : Madhwi Sharma
M.Sc. Biotechnology (2nd Year)
CUH roll no. -201635

2. • Nanotechnology refers to a broad range of tools, techniques and applications that simply involve particles on the
approximate size of 1 to 100 nanometres.
• Particles of this size have some unique physicochemical and surface properties that lend themselves to novel uses such as
solutions for major problems like safe drinking water, issues in medicine, energy, agriculture and many more.
Commercial availability,
Cost effective, availability of
raw materials
Availability of technology to
manufacture the material
Environment friendly, non-
toxic
High efficiency, inertness,
compatible mechanical and
chemical properties
Properties of
nanomaterials that can
be used for various
purposes such as water
treatment.
• Water purification is the process of decontamination of
water to remove chemical, physical and even biological
impurities (depending on the stage of purification).
• Different techniques like boiling, filtration, distillation,
chlorination, sedimentation and oxidation are used for
water purification.
• Using nanotechnology, nano materials can be used in a
variety of ways to purify water. For example use of
membranes, alumina fibers, carbon nanotubes .
• Why? Increased surface area with the same volume,
electrical, optical, physical, chemical, or biological
properties at the nano level, makes chemical and biological
reactions easier.

3. Carbon nanotubes
Advantages of using nanofiltration over conventional systems: less pressure is required to pass water across the filter, higher
efficiency, large surface area, can be easily cleaned by back-flushing.
Nanofiltration: carbon nanotube membranes can remove almost all kinds of water
contaminants including turbidity, oil, bacteria, viruses and organic contaminants.
Even with smaller pore size they have fast flow rate as compared to larger pores,
possibly because of the smooth interior of the nanotubes.
Nanofilteration: Nanofibrous alumina filters and other nanofiber materials also remove negatively charged contaminants
such as viruses, bacteria, and organic and inorganic colloids at a faster rate than conventional filters.
Nanofibrous alumina filters Source: https://assets.ysjournal.com/wp-
content/uploads/2018/01/word-image8.jpeg
Nanocellulose is prepared by sulphuric acid hydrolysis and mechanical grinding method. Water purification system based on the
principle of absorption. Absorption of anionic metal species  nanocellulose materials are functionalized with a positive
charged cationic group. Absorption of cationic metal species  nanocellulose material is functionalized with the negatively
charged anionic group.

4. Using advances in macromolecular chemistry - synthesis of
dendritic polymers that can enhance filtration processes for purification of
water contaminated by different organic solutes and inorganic anions.
Dendrimers are highly branched macromolecules with controlled
composition and architecture, and monodispersity. They consist of a central
core, repeating units and terminal functional groups.
The nature of internal repeating units determines the microenvironment and
its solubilization properties, external groups determine chemical behaviour
of dendrimers in the external medium.
Cyclodextrins are cyclic polysaccharide oligomers and have a truncated-cone shape that forms a well-defined cylindrical cavity.
The interior of the cavity is lipophilic, can encapsulate various organic compounds with suitable geometry and polarity, forming
stable inclusion complexes. The outer surface of cyclodextrins has multiple hydroxyl groups, which are susceptible to further
functionalization, thus leading to diversified molecules suitable for various applications, including the removal of pesticides and
organic contaminants from water.
A dendrimer-enhanced ultrafiltration (DEUF) process for recovering metal ions from aqueous solutions has been reported.
Using poly(amidoamine) dendrimers, separation of dendrimer-Cu(II) complexes from aqueous solutions was achieved simply
by UF membranes with the appropriate molecular weight cut-off . The metal ion laden dendrimers could be regenerated by
decreasing the solution pH to 4.0, thus enabling the recovery of the bound Cu(II) ions and recycling of the dendritic polymer.
Polymer-Supported Filtration

5. Iron nanoparticles can effectively clean organic solvents that pollute groundwater.
The iron nanoparticles disperse throughout the body of water and decompose the organic solvent in place.
This method can be more effective and cost significantly less than treatment methods that require the water to be pumped
out of the ground.
Nano-sensors based on titanium oxide nanowires or palladium nanoparticles: used for analytical detection of contaminants in
water samples.
Thee existence of nanoscopic pores in zeolite filtration membranes, as well as nano-catalysts and magnetic nanoparticles can
also be used.
Iron nanoparticles
Nano-sensors
Company Product
SiREM, American Elements, Lehigh Nanotech Iron nanoparticles to treat groundwater pollutants
Campbell Applied Physics
Also working on Capacitive Deionization using
carbon aerogel
NanoH2O
Nanotechnology enhanced membranes for water
desalination
Argonide
Filter made from nanofibers is capable of removing
viruses from water

6. A schematic diagram of application of the adsorbent in
removal of oils from water surface and its reusability
process. Source: Yu et al., 2015.
Nanotechnology can be used for novel approaches to synthesize cost-efficient and environment-friendly magnetic materials
and testing their ability as potential oil spill adsorbents.
Feasibility: Employing magnetic adsorbents at the large scale in a real-world application of the adsorbents in repairing oil
leaks. Full-scale up requires major logistical parameters and extensive field tests to ensure the efficiency of the adsorbents
over the conventional treatment technologies used.
Practical utilization is dependent on a variety of factors - sea conditions: temperatures, nature of the spilled oil, etc.
Magnetic nanomaterials
The safety and adsorptive capacity.
They should be tested - possible risks or
toxicity to the surroundings before their
commercial application to water bodies.
Further research: improving the recyclability
and reusability, oil recovery after
adsorption, sorption capacity and efficiency
to find out the advantages of the magnetic
adsorbents over natural organic and
inorganic sorbents such as cotton,
agricultural wastes, carbon, etc.
Ex. - Magnetic Carbon Composites, Organo-clays with Magnetic Fe3O4 Nanoparticles

7. Photocatalytic copper tungsten oxide nanoparticles break down oil into biodegradable compounds.
The nanoparticles are in a grid that provides high surface area for the reaction, is activated by sunlight and can work in water,
making them useful for cleaning up oil spills.
Photocatalytic copper tungsten oxide nanoparticles
Use of chemical nano dispersants which contain surfactant
molecules that migrate to the oil/water interface and reduce
interfacial tension between oil and water.
With the aid of wave energy, tiny oil droplets break away from
the oil slick. These small droplets get dispersed into the water
column and remain in suspension and, thereby, become a good
source of food for the naturally occurring bacteria. The
dispersants catalyse the biodegradation process leading to the
removal of spilled oil.
Nano Dispersants
Hydrophobic Organoclays Source: https://www.nanowerk.com/spotlight/spotid=20215.php
Natural clays like bentonites which contain metallic cations and have hydrophilic character making them unsuitable sorbents for
the removal of organic compounds. Hydrophobicity can be induced in these clays by modifying them with quaternary amines.
These organophilic clays (or organoclays) are very efficient in selectively adsorbing the organic contaminants or oil from water.

8. • Developed by MIT researchers - absorbent, superhydrophobic nanowire membranes for the selective absorption of oil from
an oil-water mixture.
• Using self assembly method, they have constructed free-standing membranes comprising inorganic nanowires capable of
absorbing oil up to 20 times their weight.
Nanowire Membranes
Photocatalytic decomposition of the oil-contaminated water using
nanoscale or microscale TiO2 particles.
Disadvantages:
difficult to Recycle and narrow range of absorption : Nano-TiO2 has
great potential in the photocatalytic treatment of oil and gas
wastewater but the recovery method greatly limits its application. TiO2
can only absorb UV light which accounts for only 3% and 5% of the full
spectrum.
Nano Dispersants
Source: Liu, X.; Ruan, W.; Wang, Zhang, X.; Liu, Y.; Liu, J. The
Perspective and Challenge of Nanomaterials in Oil and Gas Wastewater
Treatment. Molecules 2021, 26, 3945.
https://doi.org/10.3390/molecules26133945
• MIT's SENSEableCity Laboratory - Sea-swarm 7 - an autonomous oil-
absorbing prototype robot 7, uses a conveyor belt covered with the
oil absorbing nano-wire mesh.

9. • Nano scavengers - a layer of reactive nanoparticles coat a synthetic core designed to be easily magnetized. The nanoparticles, for e.g. silver
nanoparticles, attach to or kill the pollutants(like bacteria). Then when a magnetic field is applied the nano scavengers are removed from the
water.
• Pellets containing nanostructured palladium and gold as a catalyst to breakdown chlorinated compounds contaminating groundwater.
• Graphene oxide to remove radioactive material from water by absorption. The graphene oxide then forms clumps that can be removed from
the water for disposal.
• Using graphene as a membrane for low cost water desalination. Graphene with holes the size of a nanometer or less can be used to remove
ions from water.
Place Development
Brown University creating water filters using short channels between graphene sheets that can allow water to pass but
blocks larger contaminates.
North-western University a nanocomposite coating that can be applied to a sponge causing the sponge to absorb oil, but not
absorb water.
Nagoya University nanocarbons modified with amino groups to remove heavy metal ions from water.
RMIT University, University of New
South Wales
filter made with nano-thin sheets of aluminium oxide which can filter both heavy metals and oils from
water.
University of Cincinnati removing antibiotics contaminating waterways. The method uses vesicle nanoparticles that absorb
antibiotics.
Pacific North-western Laboratory developed a material to remove mercury from groundwater. The material is called SAMMS, which is
short for Self-Assembled Monolayers on Mesoporous Supports

10. Concerns about the risks associated with nanomaterials.
Compared to bulk material they have greater surface area to volume ratio which can make them more
reactive than bulk materials. May lead to unrecognized and untested interactions with biological surfaces.
Further research into the biological interactions of nanoparticles should be carried out to eliminate any
possible harmful effects.
Standard nano-filters do not work on virus cells. Development of a nano filter only a few nanometers in
diameter should be capable of removing virus cells from water.
Limitations:

11. 1. Inderscience Publishers. (2010, July 28). Nanotechnology for water purification. ScienceDaily. Retrieved November 24, 2021
from www.sciencedaily.com/releases/2010/07/100728111711.htm
2. www.understandingnano.com/water.html
3. https://en.m.wikipedia.org/wiki/Nanotechnology_for_water_purification
4. Theron, J., Walker, J. A., & Cloete, T. E. (2008). Nanotechnology and Water Treatment: Applications and Emerging Opportunities.
Critical Reviews in Microbiology, 34(1), 43–69. DOI: 10.1080/10408410701710442
5. https://www.nanowerk.com/spotlight/spotid=20215.php
6. Harpreet Singh, Neha Bhardwaj, Shailendra Kumar Arya, Madhu Khatri, Environmental impacts of oil spills and their
remediation by magnetic nanomaterials, Environmental Nanotechnology, Monitoring & Management, Volume 14, 2020,
100305, ISSN 2215-1532, https://doi.org/10.1016/j.enmm.2020.100305.