I want to make a nano fluid of carbon black ( 0,1 grams) in distilled water (200ml). As carbon black is hydrophobic, there is the need of right amount of surfactant such as SDS. The SDS amount should not be too much as they form foams and if they are added to less amount the nano fluid is not stable.
Javad Hikmati
DI water is about the worst continuous phase you could select for nanoparticles as stabilizers and surfactants can be washed out destabilizing the system. You may need surfactants and stabilizers in such a system. The amount of each would be dependent on the available surface area. So, one can't comment on the exact amount needed. Yes, foaming is an issue if too much. We tend to work with surfactants in the range 1 - 5%. They are wetting agents only. The only dispersing agent is energy (sonication typically in a wet system). If one gets (significant) recombination after sonication then a stabilizer will be needed. For steric stabilization select a PEG or PEI of 30 - 50 kDa. You may find the optimum amount or citrate or phosphate may have the same effect. Take a look at:
Dispersion and nanotechnology https://tinyurl.com/y2wfzed7
@ Javad Hikmati
Particles of carbon black (soot) are not nano-sized. Therefore, you will prepare a coarse hydrophobic dispersed phase in a hydrophilic solvent (water). Such systems are thermodynamically unstable even with a stabilizer (surfactant).
As for the selection of surfactant concentration for stabilization. All powders according to the standard should be characterized by an specific surface. If you know this value and the surface area of the surfactant head on the surface of each powder particle (approximately 0.2 - 0.3 nm2), then you can determine the value of the surfactant concentration provided that it covers the surfactant with a monomolecular layer. Sometimes, two monomolecular layers are necessary for stabilization.
Particles of carbon black (soot) are not nano-sized. Therefore, you will prepare a coarse hydrophobic dispersed phase in a hydrophilic solvent (water). Such systems are thermodynamically unstable even with a stabilizer (surfactant).
As for the selection of surfactant concentration for stabilization. All powders according to the standard should be characterized by an specific surface. If you know this value and the surface area of the surfactant head on the surface of each powder particle (approximately 0.2 - 0.3 nm2), then you can determine the value of the surfactant concentration provided that it covers the surfactant with a monomolecular layer. Sometimes, two monomolecular layers are necessary for stabilization.
Particles of carbon black (soot) are not nano-sized. Therefore, you will prepare a coarse hydrophobic dispersed phase in a hydrophilic solvent (water). Such systems are thermodynamically unstable even with a stabilizer (surfactant).
As for the selection of surfactant concentration for stabilization. All powders according to the standard should be characterized by an specific surface. If you know this value and the surface area of the surfactant head on the surface of each powder particle (approximately 0.2 - 0.3 nm2), then you can determine the value of the surfactant concentration provided that it covers the surfactant with a monomolecular layer. Sometimes, two monomolecular layers are necessary for stabilization.
Thanks Yuri Mirgorod and Alan F Rawle for the help.
The reason for distilled water is that I am using the solution for electrolysis of water to produce hydrogen. The reason of using carbon black nanoparticles is that carbon black nanoparticles in added fluid increases the thermal conductivity of the fluid and enhance heat transfer.
As the current flow and hydrogen production rate depends on temperature, using nano fluid could enhance hydrogen rate and thus decreases the voltage needed.
I use light to increase the solution temperature and hence the nanoparticles absorbs more radiation compared to none-nonofluid solution.
Javad Hikmati
I guess you know if you electrolyze pure water then distortion of the electrical field occurs ('polarization') and electrolysis is prevented. It's normal to add a drop of sulfuric acid to the system and electrolysis then takes place unhindered.
Thermodynamically, your statement 'using nano fluid could enhance hydrogen rate and thus decreases the voltage needed' is incorrect. The potential difference is simply as a result of the reaction taking place.
Alan F Rawle I am using a 31 V DC Battery source for the electrolyzer and runs the tests for 30 minutes each time. using Halogen light bulb as a light source does increase ( light radiation directly at the system)the temperature. As the temperature increases, the current flowing in the electrolyzer increases and the rate at which hydrogen gas is produced also increases as a function of current.
For example when light bulb is used the amount of hydrogen gas produced is almost twice as without light in the same amount of time and for the same salt concentration. When Carbon Black is added to the solution and using light again increases further the amount of hydrogen produced.
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nano