*2.5. Distribution Coe*ffi*cient (Kd)*

The distribution coefficient (Kd) (L/kg) was calculated according to the following formula:

$$\mathbb{K}\_{\rm d} = q\_{\rm c} / \mathbb{C}\_{\rm c} \tag{3}$$

where *Ce* is the equilibrium concentration of ion in the solution (mg/L) and qe is the amount of ion adsorbed per kg of adsorbent at equilibrium (mg/kg).
