Acid activation of coconut shell carbon (CSC) using
phosphoric acid (forming ACSC) improved the electrostatic
interaction between chitosan and the ACSC. Thus, more active
sites were available for the adsorption of Zn at low pH conditions.
In their own study, Olin et al. [33] reported enhancement
of hydrophilic property and hence improvement in the hydrodynamic
flow of metal ion to the acidic surface oxides on the
carbon surface.