What does the carbon (GAC) filter effectively remove from water?

The GAC (granular activated carbon) filter is particularly effective at removing chlorine and chloramine from water through a process known as adsorption. In this process, the contaminants adhere to the surface of the activated carbon, which has a large surface area due to its porous structure. This allows GAC filters to trap these chemicals efficiently and improve the taste and odor of the water.

Chlorine and chloramine are both commonly used disinfectants in municipal water treatment, aimed at killing harmful microorganisms. However, they can impart unpleasant tastes and odors to drinking water. The ability of GAC filters to adsorb these compounds is why they are widely used in water purification systems.

Other methods mentioned in the options do not accurately describe the function of GAC filters. For instance, ion exchange primarily targets dissolved ions and does not focus on chlorine and chloramine. Filtration by particulate matter does not apply as effectively to these specific chemicals, as they are not particulate but rather dissolved substances in the water. Lastly, precipitation is a process used for removing minerals like calcium and magnesium, which is not applicable to the carbon filtration system that specifically targets organic compounds and certain chemicals like chlorine and chloramine.