Removal of formaldehyde by activated carbon filters modified with inorganic ammonium salts
负载无机铵盐改性活性炭纤维对甲醛去除能力的影响

We investigated the efficiency of formaldehyde removal by activated carbon filters (ACF) modified by inorganic ammonium salts,such as ammonium chloride、ammonium fluoride、ammonium oxalate、ammonium sulfate、ammonium persulfate,and triethanolamine.Many parameters,including mass fractions of different ammonium salts,heating temperatures (60℃ and 160℃) and heating times (2 h and 12 h) were examined for their effects on the removal efficicncies.The ammonium salts significantly enhance the ACF performance for formaldehyde removal,with efficiencies higher than 50%.Ammonium oxalate has the highest removal efficiency (67.7%) among all the investigated salts.SEM (scanning electron microscopy) images of ACF modified by ammonium salts indicate that a large quantity of the salts tend to accumulate on the surface of ACF,rather than to enter its pores.As a result,the exposure area of ACF is decreased,but its adsorption performance is little influenced.In conclusion,employing ACF modified by inorganic ammonium salts is a promising method of formaldehyde removal.