Language
Country/Area
No result found
How do water molecules pass through membranes? Uncover the mystery of osmotic pressure!
Osmotic pressure refers to the minimum pressure required to prevent pure solvent from entering the solution through a semipermeable membrane. It is also a measure of the tendency of a solution to absorb pure solvent through the osmotic process. Osmotic pressure is an extremely important factor for many biological and chemical processes, and the corresponding phenomenon of osmosis is crucial in cell functions and water handling.
Osmosis and its basic theory
During the osmosis process, when two solutions of different concentrations are separated by a selectively permeable membrane, solvent molecules preferentially flow from the less concentrated solution to the more concentrated solution. This phenomenon will eventually continue until a state of equilibrium is reached. According to the research of scientist Jacobus van 't Hoff, we can express the quantitative relationship between osmotic pressure and solute concentration as follows:
The proportional relationship between osmotic pressure and solute concentration means that osmotic pressure is a property of condensation.
Application of osmotic pressure
Osmolality measurements can help us determine molecular weight. This phenomenon is not only widely used in chemistry, but also of vital importance in biological cells. How do organisms regulate osmotic pressure, such as the following key states:
- Hypertonicity can cause cells to shrink.
- Hypotonicity causes cells to swell.
- Isotonicity does not change the cell volume.
When biological cells are in an environment of low osmotic pressure, water molecules will enter the cells, causing water to accumulate inside the cells, thereby causing the cells to swell. In plant cells, the cell wall limits expansion. This internal pressure is called turgor pressure. Turgor pressure allows plants to grow upright and affects the opening and closing of plant stomata to a certain extent.
Reverse Osmosis and Water Treatment
The basic principle of osmotic pressure also led to the development of reverse osmosis, a widely used process for water purification. The principle used in the water treatment system is to place water in a chamber with a pressure greater than the osmotic pressure. A portion of the chamber is passed through a selectively permeable membrane, through which water molecules can pass, but solute particles cannot. This technology is particularly suitable for desalination of seawater and is widely used around the world to obtain drinkable water.
The osmotic pressure is about 27 atmospheres (atm) of seawater, which reminds us of the impact of the natural environment on organisms and water bodies.
Osmotic pressure measurement and its importance
In order to measure osmotic pressure, scientists invented a filter (Pfeffer cell), which can effectively evaluate the changes in osmotic pressure of solutions under different states. This measurement is critical to a wide range of chemical and biological research, furthering our understanding of how osmotic phenomena impact life and environmental sciences.
With the increasing severity of global environmental problems, the protection and utilization of water resources has become an important issue. We can't help but ask: In the face of increasingly tight water resources, how can science and technology further promote the sustainable use of water resources?
