Advancement in environmental remediation in the field of nanotechnology

1. GOVIND BALLABH PANT UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
Collage of Basic Science and Humanities
Department of Environmental Sciences
Presented by,
Anusha B V
52717
M.Sc (Environmental
Science)
Applications of
nanotechnology in
Environmental
management

2. CONTENTS
■ Introduction
■ Nanotechnology
■ Historical evidences
■ Nanomaterials
■ Types of Nanoparticles
■ Approaches to synthesize nanoparticles
■ Nano scale effects on properties
■ Environmental applications
■ Nano toxicology
■ Research paper
■ Conclusion
■ References

3. • Nano -Greek “DWARF” and it means one-billionth (10-9) of
a meter.
• Nanometers are important because they are the size scale of
atoms and molecule.
1 nm = 0.000000001 m
1nm = 10-9m
INTRODUCTION

4. Just how small is “Nano”?
■ A sheet of paper is about 1,00,000 nanometers
thick.
■ A strand of human DNA is 2.5 nanometers in
diameter.
■ A human hair is approximately 80,000- 100,000
nanometers wide.
■ One nanometer is about as long as your fingernail
grows in one second.

5. Nanotechnology is the creation and use of materials or devices at
extremely small scales.
“Nanotechnology is the understanding and control
of matter at dimensions between approximately 1
and 100 nanometers, where unique phenomena
enable novel applications.”
National Nanotechnology Initiative (NNi)
NANOTECHNOLOGY

6. • Predicted several aspects and advancements in the field.
• Use of advanced microscopes to view materials at extremely
small sizes, as well as the development of new fabrication
methods.
Concept first introduced by American
physicist Richard P. Feynman (1918-88)
“There’s Plenty of Room at the bottom”
American Physical Society meeting at the California
Institute of Technology (Cal Tech) on December 29, 1959

7. Nobel Prize in
Physics, 1965

8. Image of gold
nanoparticle in the
Lycurgus cup
Green = Reflected Light
(Illuminated from outside)
Red = Transmitted Light
(Illuminated from inside)
• Dichroic glass (glass containing multiple
micro-layers of metals or oxides)
• Gold & Silver nanoparticles present in the
glass cause this ancient object to change
colour when subjected to different angles
of light.
HISTORICAL EVIDENCES

9. Gold-painted stained glass windows
~ 1000 Years Ago
European church windows
are filled with glass colored
with nanoparticles of gold

10. Characteristics
1. Size: Any one dimension is < 100 nm across
2. Type: Natural, Incidental or Engineered
3. Form: Amorphous, crystalline, polymeric or
composites
4. Shapes : Spheres, tubes, rods, cones and fibres
5. Non-metal (e.g., carbon), metallic (e.g., Au, Ag),
semiconductor (e.g., Cd, Se)
NANOMATERIALS

11. 1. Naturally occurring
2. Incidental
3. Engineered
TYPES OF NANOPARTICLES

12. 1. Sea spray
2. Mineral composites
3. Volcanic ash
4. Viruses
5. Fine sand and dust
1. Naturally Occurring
Sea spray
Volcanic ash• Mineral composites
Viruses
Fine sand

13. Produced as a result of by-product of a process –
By product of combustion, industrial manufacturing and
other human activities
2. Incidental nanoparticles
Cooking smoke Diesel exhaust
Poorly controlled size and shape
Jumble of different elements

14. Sandblasting
Welding fumes
Industrial effluents
Large-scale mining – Coal fly ash

15. Examples :
1. Metals
2. Quantum dots
3. Bucky balls/nanotubes
4. Sunscreen pigments
5. Nano capsules
3. Engineered Nanoparticles
• Intentionally produced material that has a size in 1, 2, or 3-
dimensions of typically between 1-100 nm.
• Very precisely controlled sizes, shapes, and compositions.

16. ■ “Top-down” – Larger
materials carved into small ones
(like a sculpture).
■ Patterning :
(using photolithography) and
etching away material.
■ Building integrated circuits
suitable for making
interconnected and integrated
structures such as in electronic
circuitry.
■ “Bottom-up” – Assembling
smaller components (like
building a car engine).
■ Self-assembly of atoms and
molecules, as in chemical and
biological systems.
APPROACHES TO SYNTHESIZE NANO PARTICLES

17. 1. Color
2. Melting point
3. Boiling point
4. Band gap
5. Optical properties
6. Electrical properties
7. Magnetic properties
8. Structure
9. Chemical reactivity
10. Mechanical strength
PROPERTIES OF NANOPARTICLES

18. Gold (Au) Gold Nano
Color Yellow Red
Electrical
Conductivity
Conductive
Loses conductivity at 1-
3 nm
Magnetism Non-magnetic
Becomes magnetic at 3
nm
Chemical Reactivity Chemically inert Catalytic
Physical and chemical properties
changes between gold and gold nanoparticles:

19.  Copper : Opaque - Transparent
 Platinum : Inert - Catalyst
 Aluminum : Stable material - Combustible
 Silicon : Insulators – Conductors
 Carbon : 100 times stronger than steel
At Nano scale

20. Cadmium telluride quantum dots of between 2.5 and
5 nm in size as the colour changes from green to red
Colour Change
The diameter of gold nanoparticles determines the
wavelengths of light absorbed. The colors in this
diagram illustrate this effect.

21. Gold nanoparticles - properties
Bulk Gold
mp = 1064° C
Color = gold
1 nm gold particles
mp = 700 °C
lmax = 420 nm
Color = brown-yellow
20 nm gold particles
mp = ~1000 °C
lmax = 521 nm
Color = red
100 nm gold particles
mp = ~1000 °C
lmax = 575 nm
Color = purple-pink

22. Properties Behavior
Catalytic Better
Electrical Increased electrical conductivity in ceramics
Increased electric resistance in metals
Magnetic Superparamagnetic behavior
Mechanical Improved hardness and toughness of metals and alloys
Ductility and super plasticity of ceramic
Optical Spectral shift of optical absorption
Biological Increased permeability
NANO-SCALE EFFECTS ON PROPERTIES

23. ■ Nanotechnologies offer
numerous opportunities to
prevent, reduce, sense and
treat environment
contamination.
■ Nanotechnologies can
enhance and enable pre-
existing technologies and
develop new ones.
ENVIRONMENTAL APPLICATIONS

24. I. Remediation
II. Environmental Sensing
III. Pollution prevention
IV. Carbon capture
V. Energy
Potential applications of nanotechnology

25. I. Remediation
1. Nano particles
2. Bimetallic iron nanoparticles
3. Semiconducting nanoparticles
4. Dendrimers
5. Magnetic nanoparticles
6. Aerogels and solid absorbents
7. Nano filters and membranes

26. ■ Nano-sized iron(VI) powders are
used. No toxic by-products are formed
■ The use of zero-valent (Fe0) iron
nanoparticles for the remediation
of contaminated groundwater and
soil.
1. REMEDIATION USING NANOPARTICLES

27. ■ A nanoparticle–water slurry
injected to the contaminated
ground water.
■ Contaminant levels around
the injection level is reduced
in a day or two.
■ The nanoparticles do not
change by soil acidity,
temperature or nutrient
levels.
REMEDIATION OF GROUNDWATER

28. Bimetallic iron nanoparticles, such as
iron/palladium, have been shown to be more
active and stable than zero-valent iron
nanoparticles.
2. REMEDIATION USING BIMETALLIC
IRON NANOPARTICLES

29. ■ Semiconducting nanoparticles made of TiO2 and ZnO are used
in photocatalytic remediation.
■ They produce an electron-hole pair when irradiated with a
light.
■ TiO2 and ZnO are capable of transferring the charge to organic
pollutants (such as halogenated hydrocarbons) and induce their
oxidation to less harmful by-products, such as CO2, H2O and
other species.
3. REMEDIATION USING
SEMICONDUCTING NANOPARTICLES

31. ■ Nanomaterials are able to remove metal
contaminants from air.
■ Silica-titania nanocomposites transform the
elementary mercury from the vapours coming
from combustion sources to a less volatile form
(mercury oxide).
3. REMEDIATION USING
SEMICONDUCTING NANOPARTICLES

32. 4. REMEDIATION USING DENDRIMERS
■ Dendrimers are highly branched
polymers with controlled
composition and nanoscale
dimensions.
■ Removal of metal contaminants.
■ Act as “cages” and trap metal ions
and metals, making them soluble in
appropriate media or able to bind to
certain surfaces.
■ Industrial process
■ Light harvesting material

33. 5. REMEDIATION USING MAGNETIC
NANOPARTICLES
■ Researchers from Rice University have
shown that nanoparticles of rust can be
used to remove arsenic from water using a
magnet.
■ Arsenic sticks to Nano-sized rust
(10 nm, Iron oxide) tends to be magnetic,
it is removed from water using a magnet.

34. 6. REMEDIATION USING AEROGELS
AND SOLID ABSORBENTS
■ Use of aerogels (a nanomaterial) modified with hydrophobic
molecules to enhance the interaction with the oil.
■ These aerogels have very large surface area so they can absorb
sixteen times their weight of oil.
■ A company (Interface Scientific Corporation) has developed a new
nanomaterial which is very effective in remediating oil spills.
■ The company claims that the nanomaterial can absorb 40 times its
weight in oil.

35. 7. NANO-MEMBRANES AND NANO-FILTERS
■ Nano-filters, Nano-adsorbents and Nano-
membranes used for decontaminating water
and air.
■ “Nano-traps” designed for a certain
contaminant having a specific pore size and
surface reactivity.
■ Scientists at Rice university developed
reactive Iron oxide ceramic nano
membranes (ferroxane membranes) that are
capable of remediating organic waste in
water.

36. ■ Filters and membranes are engineered to chemically react with the
contaminant and convert it to a non-toxic product.
■ Researchers at the University of Tennessee developed a nanofibers for
the removal of micro-organisms via filtration and can also kill them on
contact.
■ Researchers from the University of California developed a reverse
osmosis (RO) Nano membrane for seawater desalination and
wastewater remediation.
■ The membrane is made of a uniquely cross-linked matrix of polymers
and engineered nanoparticles designed to draw in water ions but repel
contaminants.

37. Super-hydrophilic filters
■ Nano-filters allow filtering water
from contaminants such as arsenic
and other heavy metals.
■ “LifeSaver Bottle” ( a commercial
product) has a super-hydrophilic
filter inside that can block material
up to 15nm in size, which includes
viruses and bacteria.
■ On site filtration.

38. Desalination using Carbon nanotubes

39. II. Environment Sensing
■ Protection of environment requires rapid,
sensitive detection of pollutants with
molecular precision.
■ Sensors are now being used for the
identification of toxic chemical compounds at
ultra low levels (ppm and ppb) in industrial
products, chemical substances, water, air and
soil samples, or in biological systems.
■ Nanotechnologies can improve current sensing
technology.

41. III.Pollution Prevention
■ Reduction of waste in manufacturing processes.
■ Reduction of the use of harmful chemicals.
■ Reduced emission of greenhouse-effect.
IV. Carbon capture
■ Photo catalyst consisting of silica Nano springs coated with the
combination of Titanium oxide.

42. ■ Enhanced reactivity
■ Increased surface to mass ratio
■ Enhanced permeation
NANO TOXICITY

43. EFFECTS
Short term exposure
■ Inhalation in gas phase
■ Skin contact in solution
■ Oral ingestion
Long term exposure
■ Soil adsorption
■ Water dissolution
■ Biodegradation issues

44.  Algae: Nanoscale TiO2 affects algal growth and photosynthetic activity.
 Microbes: AgNPs damaged the cell wall of Escherichia coli, leading to
increased cell permeability and ultimately cell death.
 The toxicity of AgNPs has been reported in heterotrophic (ammonifying /
nitrogen fixing / plant growth promoting rhizobacteria) and chemolithotrophic
bacteria.
Specific effects on living system

45. ■ Nano zerovalent iron particles (nZVI) particles exhibited a bactericidal
effect on Escherichia coli.
■ Fish: Swollen epithelium cells, missing scales, black particles deposited
on the surface and few tactic pillar cells.
■ Rodents: Nanoparticles have the ability to cross biological barriers ,
where they cause oxidative stress.

47. ABSTRACT
CdSO4-doped TiO2 nanoparticles are introduced as a
powerful and reusable photocatalyst for the photocatalytic
degradation of methomyl pesticide in concentrated
aqueous solutions.

48. Materials and Methods
■ Preparation of CdSO4-doped TiO2 nanoparticles
■ Photocatalytic activity measurements
• Methomyl (99.8%) was obtained.
• Different concentration of 300, 500, 1,000, and 2,000 mg/l was prepared.
• 100mg of catalyst was added to 50ml of each solution.
• Exposed to natural atmospheric environment on sunny day
(May,2012between10a.m.and6p.m.).
• The samples were taken at regular intervals of time, and the concentration of the
remaining methomyl was measured by recording the absorbance at 233nm using a
UV–visiblespectrophotometer.
• The samples were centrifuged to remove the photocatalyst NPs.
■ Characterization: Images of the nanoparticles were obtained via transmission electron
microscopy (TEM, JEM-2010, JEOL, Japan).

49. RESULTS
■ Nanoparticles eliminated the pesticide under the sunlight
radiation within a very short time (less than 1 h), with a
removal capacity reaching 1,000 mg pesticide per gram of the
introduced photocatalyst.
■ Methomyl decomposes into CO2,H2O, NO3
−, and SO4
−,
indicates successful and complete elimination of the pesticide.

50. Fig 1. EDX analysis
for the obtained
powder after the
calcination process.
Fig 2. TEM (a) and
HR-TEM (b) images
of the obtained
powder. The marked
area represents the
CdSO4 NPs.

51. Fig 3. Effect of methomyl concentration on the UV absorbance
(a)the relationship between the concentration and the absorbance intensity at a
wavelength of 233nm.
(b). The inset represents the chemical structure of methomyl.

52. Fig 4. Influence of the initial methomyl concentration on its photodegradation using
TiO2/CdSO4 NPs
(a) The utilized catalyst was 100 mg, and the solution volume was 50 ml.
(b) and the corresponding percentage removal.

53. Fig 5. Effect of temperature on the
methomyl photodegradation
capacity.
Fig 6. Schematic diagram
illustrating the distinct
photocatalytic performance of
the introduced nanoparticles.

54. CONCLUSION
■ Drying, grinding, and calcination of the formed mixture lead to produce
small size CdSO4-dopedTiO2 nanoparticle.
■ The formed nanoparticles have distinct photocatalytic activity towards
methomyl degradation regardless of the methomyl content.
■ The removal capacity reaches to 1,000 mg per gram photocatalyst

55. ■ Technology can to boon as well as a curse.
■ Compared to conventional or other emerging pollutants , NPs pose
some new challenge to scientists.
■ Less is known about the reactivity and behavior.
■ Recycling not possible.
■ Risk assessment of long term exposure to engineered nanoparticles.
■ Limited evidence of safety.
CONCLUSION

56. Aitten, R.J., Chaudhry, M.Q., Boxall, A.B.A., and Hull, M., 2006
Manufacture and use of nanomaterials: current status in UK and gloabal trends.
Occup. Med. 56,300-306.
Bahareh, A., Shawninder, C., Ali Akbari, Vanessa, C., Mehrnoosh, A., Subhasis, G., and
Nathalie Tufenkji. 2018.Amendment of Agricultural Soil with Metal Nanoparticles:
Effects on Soil Enzyme Activity and Microbial Community Composition. Environ.
Sci. Technol. DOI: 10.1021/acs.est.7b05389
Barakat, N.A.M., Nassar, M.M., Farrag, T.E., and Mahmoud, M.S. 2014.
Effective photodegradation of methomyl pesticide in concentrated solutions by novel
enhancement of the photocatalytic activity of TiO2 using CdSO4 nanoparticles.
Environ Sci Pollut Res (2014) 21:1425–1435)
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