Nanoparticles suspended in liquids is termed as nanofluids. Nanofluids with controlled microparticles showed superior thermal diffusivity and plays a vital role in enhancing mass transfer and kinetics in reduced dimensions. Milli channels embedded with nanoparticles show added advantage in the liquid-liquid extraction rate. These nanoparticles are prepared with a controlled microstructure with a very high degree of precision by biochemical hydrothermal processing. Nanoparticle assisted mass transfer acts as an effective tool for process intensification, especially in designing of chemical operations like extraction, Microreactors, Gas-liquid extraction.

1. Nanomaterials
Nanomaterials are chemical substances or materials that are
manufactured and used at a very small scale. Nanomaterials are
developed to exhibit novel characteristics compared to the same
material without nanoscale features, such as increased strength,
chemical reactivity or conductivity.
 Materials of which a single unit small sized between 1 and
100 nm.
 High surface to volume ratio.
 Higher chemical reactivity and thermal conductivity
 Very high Industrial potential Especially in automobile,
aerospace and chemical industries.

2. Nanomaterials Conti.
• Two principal factors cause the properties of
nanomaterials to differ significantly from Bulk
materials:
Increased relative surface area
Quantum effects.
• These factors can change or enhance
• properties such as reactivity, strength and
• electrical characteristics.

3. Classification of Nanomaterials (Based on
dimensionality of material)
Nanomaterials could be 1D,2D or 3D in nature.
 One dimension in nanoscale (Other two dimensions are extended)
• Thin films
• Surface Coatings
• Computer chips
 Two dimensions in nanoscale (Other one dimension is extended)
• Nanowires
• Nanotubes
 Three dimensions in nanoscale
• Nanoparticles
• Precipitates
• Colloids
• Quantum dots (tiny particles of semiconductor material)
• Nanocrystalline materials

4. Properties of nanomaterials
• Nanomaterial have their specific colour
depending on size of nanomaterial and may
be different from bulk material(like Gold
nanomaterial is red in colour rather than
golden colour).
• Nanomaterial when irradiated with UV light,
emit visible light.
• Melting point of nanomaterials is always lower
than the bulk material.

5. Different types of nanomaterials
Nano cage
Carbon nanotubes
Buckminster
fullerene Nanodrugs
Core shell
nanoparticles
Nanospheres
Nanorods

6. Why nanomaterials could be effective
tools for process intensification
Surface Effects
As a particle decreases in size, a greater proportion
of atoms are found at the surface compared to
those inside. For example, a particle of
• Size-30 nm-> 5% of its atoms on its surface
• Size-10 nm->20% of its atoms on its surface
• Size-3 nm-> 50% of its atoms on its surface
Nanoparticals are more reactive than large
particles (Catalyst)

7. Potential nanoparticles
• Metallic nanoparticles
Gold, Silver, Palladium, platinum
• Metal oxide
Silicon dioxide(SiO2), Alumina (Al2O3), MgO, ZnO,
TiO2, ZrO2.
• Carbon
Graphene oxide(GO) , Multiwall Carbon nanotubes
(MWCNT), Fullerene , Single walled Carbon
nanotubes (SWCNT).

8. Nanomaterial Synthesis
• Top down approach
The top-down approach of nanoparticle synthesis is a destructive approach in
which larger molecules fragmented into smaller units, these units further
converted into nanoparticles of desired size and shape. Top-down approaches
are mostly physical or mechanical synthesis processes eg. milling, physical
vapor deposition, laser ablation, chemical etching, and sputtering.
• Bottom Up approach
Bottom-Up synthesis is a building up approach and it approaches in a reverse
manner as the nanoparticles are formed from relatively simpler molecules.
Most of the processes in this approach is either chemical or biochemical
excepting some process like spinning. The bottom-up approach is also known
as a constructive approach or building up approach.

9. Various Synthesis routes of nanomaterials
..
Typical synthesis routes of Nanoparticle Preparation
Nanoparticle Synthesis
Bottom-Up Synthesis Top-Down Synthesis
Chemical synthesis
Chemical & Biological
Synthesis
Biochemical Synthesis
Physical Synthesis
1. Mechanical Milling
2. Chemical Etching
3. Laser Ablation
4. Physical Vapor Deposition
5. Electron Explosion
6. Sputtering
7. Thermal Decomposition
8. Non Lithographic
1. Plasma Synthesis
2. Sol-gel Process
3. Laser Pyrolysis
4. Chemical Vapour
Deposition(CVD)
5. Molecular &
Atomic
Condensation
6. Spinning
7. Pyrolysis
1. Hydrothemal
Synthesis
2. Green Synthesis or
Biosynthesis
a. Plant synthesis
b. Yeast , Enzymatic
& Bacteria
synthesis

10. Potential applications
• Mass transfer enhancement
1. Gas-Liquid systems (CO2 capturing, absorption)
2. Liquid-Liquid systems(Extraction )
• Heat transfer enhancement
1. Evaporation
2. Boiling
• Chemical kinetics enhancement

11. Effect of velocity on effective absorption in presence of
nanoparticles
A.M. Ghanadi, A.H.Nasab, D. Bastani , A.A.S. Kordi , The Effect of Nanoparticles on the Mass Transfer in Liquid–Liquid
Extraction , Chem. Eng. Comm. 202 (2015) 600–605.
Crosscurrent and eddies at higher velocities adhere nanoscale movement affect mass
transfer process at higher velocities.

12. Effect of nanoparticle concentration on mass transfer
coefficient
Nematbakhsh, G., & Rahbar-Kelishami, A. (2014). The Effect of Size and Concentration of Nanoparticles on the
Mass Transfer Coefficients in Irregular Packed Liquid–Liquid Extraction Columns. Chemical Engineering
Communications, 202(11), 1493–1501.
 Overall mass transfer coefficient initially increase with increase of nanoparticles
concentration and then decrease with increase in concentration.
 Mass transfer coefficient decreases with increase in volumetric flow rates .
Nanoparticle accretion and agglomeration at higher concentration is responsible
for this phenomenon.

13. Effect of nanoparticle size on mass transfer coefficient
Nematbakhsh, G., & Rahbar-Kelishami, A. (2014). The Effect of Size and Concentration of Nanoparticles on the
Mass Transfer Coefficients in Irregular Packed Liquid–Liquid Extraction Columns. Chemical Engineering
Communications, 202(11), 1493–1501.
 Overall mass transfer coefficient decrease with increase of nanoparticles size and
increase in volumetric flowrates.
Higher surface/volume ratio is responsible for increase in mass transfer coefficient
with smaller size nanoparticles .