Study on the adsorption of methylene blue by cross-linked γ-PGA

Cross-linked γ-PGA and methylene blue were applied as the sorbent and adsorbate respectively.The influences of adsorption time,pH values of the solution and the initial concentrations of methylene blue on the adsorption quantities of methylene blue by cross-linked γ-PGA were studied.The experimental results demonstrate that the adsorption quantities increase with the increasing of adsorption time,and reach saturation after 16 h.The adsorption quantities in the basic range are higher than those in the acidic range.Meanwhile,the adsorption quantities increase with the increasing of the initial concentrations of methylene blue,and reach saturation finally.The study of adsorption mechanism demonstrates that the adsorption of methylene blue by cross-linked γ-PGA is Langmuir type,and the saturation adsorption quantity is 0.878 mg/mg.