How does reverse osmosis function in water treatment?

Reverse osmosis functions by forcing water through a semi-permeable membrane, which is the hallmark mechanism of this water treatment process. In reverse osmosis, water pressure is applied to overcome the natural osmotic pressure, allowing water molecules to pass through the membrane while effectively rejecting a majority of dissolved solids, contaminants, and larger molecules. This process is particularly effective in reducing impurities such as salts, heavy metals, and other dissolved substances, making it a popular and efficient method for producing potable water from various sources.

The use of a semi-permeable membrane enables the selective passage of water while restricting the passage of contaminants, thereby enhancing the quality of the treated water. This method is critical in applications requiring high purity water, such as in drinking water systems, desalination plants, and various industrial processes.

In contrast, other options presented describe different water treatment methods that do not utilize the principles of reverse osmosis. Boiling water is effective for killing pathogens but does not remove chemical contaminants. Charcoal filtration absorbs certain impurities but is not based on membrane technology. Adding chemicals can improve taste but does not address the removal of pathogens or contaminants directly through filtration or separation mechanisms.