What is the role of activated carbon in water purification?

Activated carbon plays a crucial role in water purification primarily through its ability to absorb pollutants. It features a vast surface area and porous structure, which allows it to capture and hold various contaminants such as organic compounds, chlorine, chlorinated solvents, and other impurities present in water. This absorption process helps improve water quality by removing substances that can affect taste, odor, and safety.

Additionally, activated carbon is particularly effective in removing volatile organic compounds (VOCs) and other harmful chemicals, making it an essential component in many water treatment systems. This is why it's widely used in both municipal water treatment facilities and household water filters.

The other options do not accurately describe the main function of activated carbon in water purification. While sterilization refers to the elimination of microorganisms, this is not a function of activated carbon. Instead, sterilization typically involves physical or chemical methods such as chlorine disinfection or UV light treatment. Increasing water acidity and softening the water relate to entirely different processes; acidity involves altering pH levels, while softening refers to the reduction of hardness minerals like calcium and magnesium in water.