Tannic Acid-Zinc Crosslinked Chitosan Hydrogels: High-Performance adsorbent for Titan Yellow removal from wastewater

Abstract The capability to engineer hybrid materials with specific properties drives innovation across multiple technological fields. A straightforward wet chemical procedure was initially used to make chitosan zinc hydrogel (ChZn) to remove titan yellow (TY) dye from water to use hybrid material for water purification. The maximal adsorbent dose of 22.1 mg for 10.0 mL of 500 mg L-1 TY showed a removal capacity of 384.45 mg g-1 at optimum pH and a contact time of 25 minutes. To improve the adsorption capacity of ChZn, it was crosslinked with tannic acid (TA). Remarkably, under optimized parameters, TA-zinc crosslinked chitosan hydrogels (ChZnTA) exhibited a removal capacity of 505.05 mg g-1. The adsorption process adheres to Pseudo-second order kinetics and aligns with the Freundlich isotherm. The ChZnTA interaction with TY dyes indicated interactions resulting from hydrogen bonding, π-π stacking, van der Waals, and electrostatic forces. Furthermore, desorption-regeneration studies demonstrate that even after being used for up to three cycles, ChZnTA and ChZn effectively eliminate TY up to 79.9% and 53.8%, respectively.