Aeration Process for Removing Radon from Drinking Water - A Review

摘要

This paper presents information on various radon elimination techniques and presents knowledge on anticipated elimination performances following literature. The technologies assessed in this review comprise different aeration techniques and granular activated carbon (GAC) as tools to eliminate and decrease radon in potable water. Because radon does not bound to water molecules, it is not dissolved. Radon's low solubility and its elevated vapor pressure imply that it strongly partitions into the air through diffusion. For the reason that it readily diffuses from water to air, radon is scarcely observed in surface waters and is firstly trouble in groundwater and radon is easily removed through aeration processes. Aeration transmits the radon pollution from water to air, so precautions should be taken to avoid such air contamination hazards. Aeration is not sufficient for removing radon from drinking water; it should be supported by adsorption method. Air is mainly composed of nitrogen (N_(2(gas)), ～80%) and oxygen (O_(2(g)), ～20%). N_2 is hydrophilic and O_2 is hydrophobic. Injecting pure O_2 into water would be more efficient than air (i.e., N_2 + O_2) in removing radon from water, thanks to its hydrophobicity. At the opposite extreme, injecting pure N_2 would be less performant, due to its hydrophilicity. Research should be made on this direction.