Fig. 7. (A and B) The chemical structure and color fading of MB and MR solution after adsorption by GA-GH; (C and D) the change of UV-vis absorption spectra of original MB (10 ppm) and MR (20 ppm) in the presence of GA-GH; (E and F) adsorption kinetic plots and curving fitting by pseudo-first-order (solid line) and pseudo-second-order (dot line) kinetic models of MB and MR on GH and GA-GH, respectively.