The adsorption amount of phenol on AC sample at adsorption time (t), qt, was calculated according to
qt ¼ V C0−Ct
ð Þ
m
ð1Þ
where qt (mg·g− 1) is the adsorption amount of phenol on AC sample at t; V (L) is the volume of the solution; C0 and Ct (mg·L−1) are the initial phenol concentration and instantaneous phenol concentration corre- sponding to t, respectively; m (g) is the mass of AC sample.