The amount of RhB adsorbed onto the four activated carbons was in the following order: K-AC > PK-AC > P95-AC > P-AC (Fig. 2).This was consistent with the changing trend of BET surface area.Taking into account the cost of activated carbon, here, our work mainly focus on the investigation of PK-AC. It was noteworthy that most of pores in PK-AC were lager than 2 nm (Fig. 1b), which were suitable to adsorb RhB. The length and width of RhB molecular were1.8 and 0.7 nm [12,13], respectively