Fig. 3. SEM images of PAC on different scales. (A) (× 1000 magnification): an overview of PAC grains scattering around; (B) (× 5000 magnification): PAC grain with visible pores on surface; (C) (× 10 000 magnification): the edges and surface of PAC grains which are potential adsorption sites; (D) (× 50 000 magnification): macropores can be seen on the surface with scale bar of 100 nm.
