Document Type : Research Article
Nowadays, supramolecular hydrogels as a new class of 3D compounds based on non-covalent interactions have attracted the attention of many scientists of different fields due to their diversity, easy preparation methods and unique characteristics compared to their covalent counterparts. Therefore, in the present study, firstly, cellulose nanoparticles were first prepared from cotton using an acid hydrolysis process and then they were functionalized with pendant citric acid and pyridine pendant groups in order to create anionic and cationic components, respectively. Then, supramolecular hydrogels were prepared through electrostatic interactions between them. The successful preparation of the hydrogel was investigated using FT-IR spectroscopy, SEM and X-ray diffraction. Morphology of the hydrogel showed a porous structure containing holes of different sizes appropriate for absorbing methylene blue. Also, the investigation of the crystal structure of the hydrogel shows its high crystallinity. Finally, the removal of cationic methylene blue dye from industrial wastewater was investigated through the absorption process and using the resulting hydrogel as an adsorbent. Also, the effect of methylene blue concentration and contact time at room temperature on the absorption efficiency was investigated. Study of the absorption kinetics showed that the absorption process follows the second-order absorption kinetics. The highest absorption capacity obtained for this adsorbent was 97 mg/g. The present study showed that the obtained supramolecular hydrogel, in addition to features such as biocompatibility, low-cost and simple preparation method, has a good potential for absorbing methylene blue.