MWCNT water vapor amount question

[compton1]

In order to grow MWCNTs I need to have certain content of water vapor
dissolved in the argon gas. The amount of water vapor can be changed with
temperature of the water that argon bubbles through. I have Argon entering a flask with water in it. The flow of the argon is 120 ml per min. It makes bubbles about 3 mm in
diameter and travels about 2 cm through the water in the flask. The bubble
is in contact with water for about 0.2s. How would I go about estimating how
much water vapor can mix with the dry argon gas when the temperature is 20C?

 

[BigJDubs]

The water vapor concentration in the argon gas can be estimated using the Dalton-Gaw Approach. This approach states that the water vapor concentration in dry air or other gases is equal to the partial pressure of water vapor in the gas multiplied by the molar mass of water vapor (18.015 g/mol) divided by the total pressure of the gas. Using the ideal gas law, we can calculate the partial pressure of the water vapor in the argon gas: Pwv = mole fraction of water vapor * total pressure of argon Pwv = (x/(1-x)) * Ptotal Where x is the mole fraction of water vapor in the argon gas. The mole fraction of water vapor in the argon gas at 20C can be estimated using Henry's Law: x = H * pw / Ptotal Where H is the Henry's Law Constant, pw is the partial pressure of water vapor and Ptotal is the total pressure of the argon gas. The Henry's Law Constant for water at 20C is approximately 0.001764 bar/mol. Therefore, the water vapor concentration in the argon gas when the temperature is 20C can be calculated as: water vapor concentration = (0.001764 bar/mol * pw) / Ptotal where pw is the partial pressure of water vapor and Ptotal is the total pressure of the argon gas.

 

[charng]

To estimate the amount of water vapor that can mix with dry argon gas at a temperature of 20C, you will need to consider the saturation vapor pressure of water at that temperature. This is the maximum amount of water vapor that can exist in equilibrium with liquid water at 20C. The saturation vapor pressure can be found using a vapor pressure table or by using the Clausius-Clapeyron equation. Once you have this value, you can calculate the amount of water vapor that can be dissolved in the argon gas by multiplying the saturation vapor pressure by the volume of the argon gas and dividing by the total volume of the system (argon gas + water). This will give you the maximum amount of water vapor that can be dissolved in the argon gas at 20C.

However, it is important to note that this calculation assumes ideal gas behavior and does not take into account any potential interactions between the argon gas and water molecules. Therefore, it is always best to experimentally determine the optimal conditions for growing MWCNTs, as the amount of water vapor needed may vary depending on the specific setup and conditions. Additionally, it may be beneficial to consider the solubility of water in argon at different temperatures, as this can also affect the amount of water vapor that can be dissolved in the gas. Overall, careful experimentation and observation will be key in determining the optimal amount of water vapor for growing high-quality MWCNTs.