Abstract: The impregnation of CuCl2 on coconut shell based activated carbon was investigated for efficient formaldehyde removals.Scanning electron microscopy (SEM) was used for morphology structure observation.Nitrogen adsorption isotherm was employed for pore structure analysis.The surface elements of activated carbon were tested by XPS.XRD was used for analyzing the crystal forms of cupric salt.Dynamic studies of formaldehyde adsorption at room temperature was carried out by adsorption performance test.The results showed that cupric salt existed in three forms,i.e.,Cu,CuCl and CuCl2.The increment of Cu loading leads to the decreasing of surface area and pore volume of activated carbon,and the increasing of average pore diameter.After modification,the surface oxygenated groups on the surface of activated carbon increased.When CuCl2 concentration was 0.5 mol/L,formaldehyde adsorption capacity(4.28 mg/g) of the modified activated carbon was 3.1 times than that of the original one(1.38 mg/g).Adsorption behavior of formaldehyde on modified activated carbons fitted Freundlich adsorption isotherm well.