Study on radiation-induced polyaniline-based cellulose gel and its adsorption of methylene blue

Abstract

In this study, polyaniline-based cellulose nanofibers were synthesized via electron beam radiation and subsequently combined with sodium alginate to fabricate a polyaniline-based cellulose-sodium alginate composite (PNC) gel through ion-induced crosslinking. The PNC gel was utilized for the adsorption of methylene blue (MB) from aqueous solutions, with a systematic investigation into the effects of key parameters, including temperature, contact time, ionic strength, pH, and reusability. The optimal radiation dose for synthesizing polyaniline-based cellulose was determined to be 70 kGy. The adsorption kinetics of MB by the PNC gel followed a pseudo-second-order model, while thermodynamic analysis revealed an enthalpy change of 28.95 kJ/mol, an entropy change of 122.13 J/mol·K, and a negative Gibbs free energy change, indicating a spontaneous and endothermic adsorption process. Notably, ionic strength had no significant impact on MB adsorption, whereas pH played a critical role, with optimal adsorption observed at pH 7. Alkaline conditions were found to alter the molecular structure of MB, significantly affecting adsorption efficiency. Furthermore, the PNC gel demonstrated excellent reusability, highlighting its potential for practical applications in dye removal. This work not only presents a novel approach for synthesizing polyaniline-based cellulose nanofibers using ionizing radiation but also provides valuable insights into the development of efficient adsorbents for the treatment of dye-contaminated wastewater.