289616.fig.004a
(a)
289616.fig.004b
(b)
Figure 4: Variation of the soluble Zn-bearing species with time. Mixing of reactants: (a) adding NaOH to ZnSO4; (b) adding ZnSO4 to NaOH. ■: Zn2+, ∘: , ▸: , : ZnOH+, ◂: , ▲: , : .