Interaction of Nanoparticles with Reservoir Fluids and Rocks …
305
2.3.1 Top-Down Process
The process in which bigger size particles are sub-divided into nanoscale size particles by various processes such as thermal, mechanical, laser ablation, and arc
discharge methods.
Thermal Decomposition
Thermal decomposition for synthesis of nanoparticles is an endothermic reaction
in which the system is subjected to tremendous heat. In the presence of an enormous amount of heat, a chemical bond exists in the substance get decomposed. During decomposition of substance some secondary substance is produced, along with
nanoparticles. A specific purification method can be adopted to separate nanoparticles from undesired secondary substances. The purification method is based on
physical state of the substance from which nanoparticles are being formed.
Mechanical Milling
Mechanical milling is one of the most popular processes for the synthesis of nanoparticles. In this process, the material is subjected to a milling process in which the
material is converted to nanoscale particles with application of strong shear stress.
The different types of millers used are ball mill, shaker mill, attrition, etc. The most
demerit of the process is the production of contaminated nanoparticles due to the
ball present in the mill.
Laser Ablation
It is the technique in which laser beam is used to produce nanoparticles. In this
process, the high laser beam is focused on the target in the solvent. The laser beam
project short pulses of energy on the tiny part of the metal to vaporize it. The vapors
later condensed to form nanoparticles in the solvent. This method applies for the
generation of nanoparticles of noble metal. It is a reliable process for the production
of nanoparticles and considered as an alternative to the chemical vapor decomposition
method (Ealias and Saravanakumar 2017).
Arc Discharge
It is one of the oldest physical methods under top-down process for the production
of nanoparticles. In the arc discharge process, two electrodes are dipped very close
to each other in the solution and subjected to high voltage. Under the high potential
difference, an electrical breakdown exists in the medium, resulting in arc discharge
305
2.3.1 Top-Down Process
The process in which bigger size particles are sub-divided into nanoscale size particles by various processes such as thermal, mechanical, laser ablation, and arc
discharge methods.
Thermal Decomposition
Thermal decomposition for synthesis of nanoparticles is an endothermic reaction
in which the system is subjected to tremendous heat. In the presence of an enormous amount of heat, a chemical bond exists in the substance get decomposed. During decomposition of substance some secondary substance is produced, along with
nanoparticles. A specific purification method can be adopted to separate nanoparticles from undesired secondary substances. The purification method is based on
physical state of the substance from which nanoparticles are being formed.
Mechanical Milling
Mechanical milling is one of the most popular processes for the synthesis of nanoparticles. In this process, the material is subjected to a milling process in which the
material is converted to nanoscale particles with application of strong shear stress.
The different types of millers used are ball mill, shaker mill, attrition, etc. The most
demerit of the process is the production of contaminated nanoparticles due to the
ball present in the mill.
Laser Ablation
It is the technique in which laser beam is used to produce nanoparticles. In this
process, the high laser beam is focused on the target in the solvent. The laser beam
project short pulses of energy on the tiny part of the metal to vaporize it. The vapors
later condensed to form nanoparticles in the solvent. This method applies for the
generation of nanoparticles of noble metal. It is a reliable process for the production
of nanoparticles and considered as an alternative to the chemical vapor decomposition
method (Ealias and Saravanakumar 2017).
Arc Discharge
It is one of the oldest physical methods under top-down process for the production
of nanoparticles. In the arc discharge process, two electrodes are dipped very close
to each other in the solution and subjected to high voltage. Under the high potential
difference, an electrical breakdown exists in the medium, resulting in arc discharge