Evaluation of the adsorption capacity of a new cellulose-based polymer

Abstract

A novel cellulose-based polymer, dicarboxymethyl cellulose (DCMC), was synthesized from cellulose and sodium 2-bromomalonate. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and Fourier-transform infrared spectroscopy (FTIR) were employed to characterize the polymer. The size of the particles ranged between 10 and 100 µm. Equilibrium and kinetic adsorption studies were performed to evaluate its suitability for methylene blue removal at different pH. Equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherms. At pH = 3, adsorption isotherms followed the Langmuir model with a maximum adsorption capacity of 887.6 mg/g. At pH = 6.4, the adsorption isotherms produced an S-shape and were fitted with the Sips model, giving a maximum uptake of 1354.6 mg/g. Pseudo second-order kinetic model provided the best fit of the experimental data. The reusability of DCMC was evaluated. After the first cycle, adsorption decreased 30%. Adsorption coupled with membrane filtration allowed complete removal. The adsorption of cytochrome C was evaluated. The adsorption process followed the Langmuir adsorption isotherm, giving a maximum uptake of 1279.6 mg/g. Pseudo second-order kinetic model adjusted well the experimental data. DCMC was successfully regenerated and reused without compromising performance. After three cycles, adsorption efficiency was above 90%.