Page 475 - Demo

SECTION II. APPLIED BIOTECHNOLOGY IN THE PHARMACEUTICAL INDUSTRY... 479molecules. Consequently, the hydrogel%u2019s capacity for further adsorption diminishes. Equilibrium was observed after 180 minutes, indicating saturation of the hydrogel%u2019s adsorption sites.3.1.3. Resorption capacity of gel beadsThe reusability of the adsorbent material was evaluated through a regeneration process. Following the initial adsorption cycle, the beads was thoroughly washed with distilled water and subsequently immersed in a 0.01 M HCl solution for 24 hours to desorb the adsorbed methylene blue. After the desorption period, the adsorbent was removed from the solution, rinsed multiple times with distilled water to eliminate residual HCl, and dried at 60%u00b0C for 60 minutes. The regenerated beads were then be subjected to a subsequent adsorption cycle to assess its performance.After multiple cycles of reuse, the adsorption capacity of the material is presented in Figure 3, indicating a reduction of 20.96%, and 37.10% after the second and third reuses, respectively. The observed decline in adsorption capacity can be attributed to the incomplete desorption of methylene blue (MB) during the regeneration process using pH adjustments, and resulting in residual MB occupying active adsorption sites.Alternative desorption methods, such as thermal treatment, are limited by the temperature sensitivity of polyvinyl alcohol (PVA), which compromises the structural integrity of the material. Despite these challenges, the material retains a considerable degree of adsorption capacity across multiple reuse cycles, although a gradual decrease was evident with successive regenerations.