*2.7. Desorption of Dyes*

Desorption of MB and CR from CNF, GnP and CNF–GnP 3:1 was performed in ethanol, acetonitrile, acetone or 400 mM NaCl at 25 ◦C. First, the adsorbents were added into 20 mL of 100 mg L−<sup>1</sup> dye solutions for adsorption at 120 rpm and then taken out from the dye solutions after 16 h. These adsorbents were transferred to 20 mL of desorption agents. After 1h, the adsorbents were removed and the dye concentration in the solution was measured. The adsorbents might again have been transferred to a fresh desorption agent and the desorption step was repeated for several cycles. Dye percentage removal (%) was calculated by Equation (5):

$$\text{Removal} \left( \% \right) = \frac{D\_{\text{t}}}{\text{C}\_{0} - \text{C}\_{\text{c}}} \times 100 \tag{5}$$

where *D*<sup>t</sup> is the concentration of dye in the desorption (mg L−1), *C*<sup>0</sup> and *C*<sup>e</sup> are the initial and final concentrations of dye in the adsorption (mg L<sup>−</sup>1), respectively.
