Activated carbon (AC) filters have been used in home water purification systems primarily to remove taste and odor. Taste and odor, although undesirable, are generally not considered unhealthy. Activated carbon is most effective at removing organic compounds such as volatile organic compounds, pesticides and benzene. It can also remove some metals, chlorine and radon.
Many organic compounds, such as chlorinated and non-chlorinated solvents, gasoline, pesticides and trihalomethanes can be adsorbed by Activated carbon. Activated carbon is effective in removing chlorine and moderately effective in removing some heavy metals. AC will also remove metals that are bound to organic molecules. Fluoride, chloride, nitrate, hardness (calcium and magnesium) and most metal ions are not removed by Activated carbon to any significant degree.
AC treatment systems are typically point-of-use (POU) - installed where they typically treat water used for drinking and cooking only. AC filters can be placed on the end of the faucet, on the countertop, or under the sink. POU systems often have a bypass so that water for purposes other than drinking and cooking can also be dispensed at the tap without being treated. This increases the life of the AC, reducing the time between filter replacements.
Our standard NeerSorb™ C series grades developed for chlorine/organic reduction claims, we also offer a number of specialized products including catalytic grades for chloramine removal, silver impregnated grades (AG series) for bacteriostatic properties, and acid washed grades (AW series) for high purity requirements. All of these product series are available in unique particle size distributions, including custom particle size ranges to meet individual customer specifications. Many grades are certified to NSF Standards.
POE system is more appropriate if a contaminant is present that poses a health threat from general use as well as from consumption. AC filters used for home water treatment contain either granular activated carbon (GAC) or powdered block carbon. Although both are effective, one study comparing GAC with block AC filters showed that the block AC filters were more effective in removing chlorine, taste and halogenated organic compounds. The amount of AC in a filter is one of the most important characteristics affecting the amount and rate of pollutant removal. More carbon in a cartridge means more capacity for chemical removal, resulting in longer cartridge lifetime. This means fewer cartridge changes and less chance of drinking contaminated water. Particle size will also affect the rate of removal; smaller AC particles generally show higher adsorption rates. Rust, scale, sand or other sediments can clog any AC filter. A solution to this problem is to place foam or cotton filters (often called sediment or fiber filters) between the cartridge and incoming water. When sediment filters become clogged, they need to be replaced or they will cause water pressure to drop. An AC filter must be deep enough so that the pollutants will adsorb to the AC in the time it takes the water to move through the filter The appropriate filter depth depends on the flow rate of water through the filter. The slower the flow rate, the better the removal. The poor performance of some end-of-faucet devices is probably due to improper filter depth. Physical and chemical characteristics of the water will also affect performance. The acidity and temperature can be important. Greater acidity and lower water temperatures tend to improve the performance of AC filters.