Bacterial cellulose microfiber reinforced hollow chitosan beads decorated with cross-linked melamine plates for the removal of the Congo red

In this epoch, the disposal of multipollutant wastewater inevitably compromises life on Earth. In this study, the inclusion of Bacterial cellulose microfilaments reinforced chitosan adorned with melamine 2D plates creates a unique 3D bead structure for anionic dye removal. The establishment of an imine network between melamine and chitosan, along with the quantity of inter- and intra‑hydrogen bonds, boosts the specific surface area to 106.68 m².g^-1. Removal efficiency and in-depth comprehension of synthesized adsorbent characteristics were assessed using batch adsorption experiments and characterization methods. Additionally, pH, adsorbent quantity, time, beginning concentration of solution, and temperature were analyzed and optimized as adsorption essential factors. Owing to the profusion of hydroxyl, amine, imine functional groups and aromatic rings, the synthesized adsorbent intimated an astonishing maximum adsorption capacity of 3168 mg.g^-1 in Congo red dye removal at pH 5.5. Based on the kinetic evaluation, pseudo-second-order (R² = 0.999), pseudo-first-order (R² = 0.964), and Avrami (R² = 0.986) models were well-fitted with the kinetic results among the seven investigated models. The isothermal study reveals that the adsorption mechanism predominantly follows the Redlich-Peterson (R² = 0.996), Koble-Carrigan, and Hill isotherm models (R² = 0.994). The developed semi-natural sorbent suggests high adsorption capacity, which results from its exceptional structure, presenting promising implications for wastewater treatment.