How osmotic membranes function

In summary, the speaker has been conducting experiments with dialysis tubing and has some questions regarding osmosis, leakage of solute through the membrane, and the rate of solvent flow through the membrane. They have found various explanations online for how osmosis works and have tried different methods to prevent leakage of solute, but have not been successful. The speaker also mentions that thermodynamics can explain osmotic pressure but there is no easy formula for the rate of solvent flow through the membrane.
  • #1
AamsterC2
51
4
I've been doing some experiments with dialysis tubing I purchased online and just have some general questions.

Firstly how does osmosis work exactly? I read that because there are less free molecules of the solvent on one side that the solvent on the other side flows in but there were lots of other explanations online as well.

Secondly everything I've found for using dialysis tubing suggests sucrose (table sugar) but after a few hours or so I notice that there is some sugar that has gotten out of the container, I've tried tying knots, rubber bands, super glue, etc to close the ends so it must be leaking out of the pores in the membrane itself. Is there anyway to prevent this? Or will some of the solute always leak out of the membrane over time?

Finally is there anyway to calculate how fast the solvent flows through the membrane? I was able to find equations for determining the pressure but nothing related to how quickly the solvent will pass through to equalize the pressure
 
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  • #2
Osmotic pressure can be explained with thermodynamical arguments, namely by the maximization of total entropy of the system and surroundings when the solutions on both sides of the membrane are equally concentrated. Unfortunately, thermodynamics can only tell us the direction of some spontaneus process, not its rate - therefore no easy formula for the flow rate through the membrane exists.
 
  • #3
hilbert2 said:
Osmotic pressure can be explained with thermodynamical arguments, namely by the maximization of total entropy of the system and surroundings when the solutions on both sides of the membrane are equally concentrated. Unfortunately, thermodynamics can only tell us the direction of some spontaneus process, not its rate - therefore no easy formula for the flow rate through the membrane exists.
Ok, thanks ^-^
 

1. How do osmotic membranes work?

Osmotic membranes are semi-permeable membranes that allow the passage of solvent molecules while blocking the passage of solute molecules. This selective permeability is due to the presence of small pores or channels in the membrane that only allow certain molecules to pass through.

2. What is the purpose of osmotic membranes?

The main purpose of osmotic membranes is to facilitate the process of osmosis, which is the movement of solvent molecules from an area of low solute concentration to an area of high solute concentration. By selectively allowing certain molecules to pass through, osmotic membranes help maintain the balance of solute concentration on either side of the membrane.

3. How do osmotic membranes differ from other types of membranes?

Osmotic membranes are designed specifically for the process of osmosis and have a unique structure that allows for the selective passage of molecules. Other types of membranes, such as filtration membranes, may have different pore sizes and allow for the passage of larger molecules.

4. What factors affect the function of osmotic membranes?

The function of osmotic membranes can be affected by several factors, including the type of solvent and solute, the concentration gradient between the two sides of the membrane, and the pressure difference across the membrane. Additionally, the material and structure of the membrane itself can also impact its function.

5. How are osmotic membranes used in scientific research and practical applications?

Osmotic membranes have a wide range of applications in scientific research and practical use. They are commonly used in processes such as reverse osmosis for water purification, desalination, and drug delivery. In research, osmotic membranes are used for studying osmotic pressure and the behavior of molecules in solution.

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