Carbon filters remove sediment but they also remove chlorine, volatile organic compounds (VOCs), odors and unpleasant tastes from water. Carbon filters contain activated carbon, which is made through a special manufacturing process that creates more bonding sites. As water passes through a carbon filter, impurities like VOCs and heavy metals become chemically bonded to the carbon. As the water works its way through the filter, a lot of unwanted impurities will become stuck to the carbon bonding sites and the water will leave the filter much more pure than it came in.Carbon filters are effective at removing the impurities that bond to carbon. Not all impurities do. Sodium, for example, is able to pass directly through carbon filters without being removed.