Bacterial cellulose and keratin reinforced PAM hydrogels for advanced dye removal: Insights from batch and QCM analyses

Industrial wastewater, particularly from textile industries, contains toxic dyes that require practical and sustainable removal technologies. Hydrogels are potential materials for this purpose due to their high water absorption capacity, but conventional designs suffer from poor mechanical strength and limited dye adsorption efficiency. In this study, we developed a bio-based hydrogel composite by reinforcing polyacrylamide (PAM) with bacterial cellulose (BC) and keratin intermediate filaments (KIF) derived from human hair. This hybrid material enhances both mechanical integrity and adsorption performance. Batch adsorption tests showed a high dye removal efficiency of 60 mg/g for methylene blue over 12 h. In contrast, QCM analysis demonstrated rapid adsorption equilibrium (15 s) under continuous flow conditions, confirming its potential for real-time wastewater treatment. The optimized 2 % KIF hydrogel achieved a compressive strength of 0.4 MPa, forming a porous structure that supports multiple adsorption-desorption cycles for reuse. Adsorption followed pseudo-second-order and Freundlich isotherm models, indicating a heterogeneous mechanism driven by electrostatic interactions and π-π stacking. By integrating sustainable biopolymers, this composite hydrogel overcomes traditional hydrogels' mechanical and functional limitations, offering an eco-friendly solution for continuous wastewater treatment and industrial dye removal.