A study on the adsorption of trichloromethane by reverse osmosis water purifiers

LIU Qing; WU Hao; WANG Weiwei

doi:10.19784/j.cnki.issn1672-0172.2025.04.009

Abstract：The Ministry of Health's"Hygiene Safety and Functional Evaluation Specifications for Drinking Water Quality Treatment Equipment-Reverse Osmosis Treatment Devices"involves two trichloromethane indicators:one requires the output water quality to be≤15 μg/L,and the other requires the removal efficiency of volatile organic compounds(trichloromethane)to be≥95%(with a spiked concentration of 300 ppb).The national drinking water hygiene standard GB 5749 specifies that the trichloromethane concentration in drinking water should not exceed 60 ppb.The concentration of trichloromethane in tap water affects the final removal efficiency of the water purifier;simultaneously,the three filter elements-pre-treated activated carbon,RO membrane filter,and post-treated activated carbon-in a reverse osmosis water purifier have different adsorption effects on trichloromethane,which are directly related to the concentration of trichloromethane in tap water.After testing and verification,it was concluded that when the trichloromethane concentration in tap water is≤30 ppb,the RO membrane filter has no significant removal effect on trichloromethane,and the overall adsorption of trichloromethane by the water purifier primarily relies on the combined action of pre-treated activated carbon and post-treated activated carbon.When the trichloromethane concentration in tap water exceeds 30 ppb,the removal is mainly dependent on post-treated activated carbon.The adsorption capacity of activated carbon for trichloromethane can be estimated at 0.05%(mass ratio).