What is the primary use of granular activated carbon filters in treating water?

Granular activated carbon filters are primarily used in water treatment to remove synthetic organic chemicals. This effectiveness arises from the unique structure of activated carbon, which has a high surface area and porous nature that allows it to adsorb a variety of contaminants. The process of adsorption occurs when the chemical compounds in the water bond with the carbon surfaces, effectively pulling these pollutants out of the water.

Synthetic organic chemicals, which can originate from a range of sources such as industrial discharges, pesticides, and pharmaceuticals, are often difficult to remove through conventional treatment methods. Granular activated carbon is particularly effective in addressing these issues, helping to improve water quality and safety for consumption or other uses.

The other options involve processes that either do not align with the primary function of granular activated carbon filters or contradict its capabilities. For instance, softening hard water usually involves ion exchange resins or chemical treatments rather than carbon filtration. Similarly, filtering out dissolved minerals is not a characteristic function of granular activated carbon, as its primary role is focused on organic compounds and not mineral content. Finally, enhancing water hardness is contrary to the function of water treatment, as this typically aims to reduce hardness rather than enhance it.