Synthesis and application of zinc-loaded carboxymethyl tamarind kernel gum and xanthan gum-based superabsorbent hydrogels to investigate the effect on sesame plant growth

The novel zinc-incorporated superabsorbent hydrogel (ZSAH) was fabricated by interpenetrating zinc micronutrient in xanthan gum and carboxymethyl tamarind kernel gum with sodium methacrylate. Various compositions of SAH hydrogels were fabricated by varying the concentrations of biopolymers, monomer, cross-linker, and initiator. Zinc chloride was incorporated in the best-swelled hydrogel for the release of Zinc as a micronutrient. Synthesized SAH and ZSAH were characterized by FTIR, SEM, and TGA techniques. The influence of various solvents, such as standard saline solution, different pH solutions (4, 9, and 12), and distilled water on the swelling degree of ZSAH. Moreover, ZSAH was utilized for controlled-release studies of zinc micronutrient in both soil and water. Moreover, the kinetic modeling of zinc release was done using Korsmeyer–Peppas and Higuchi models. It was found that the Korsmeyer–Peppas model with a higher value of regression coefficient (R²) close to unity fitted well in the zinc release pattern in soil and water. Moreover, the estimated value of diffusion exponent (n) indicated that the mechanism of zinc release followed Fickian diffusion. The ZSAH was used for the study of sesame plant growth. It was found that the number of germination of seeds count for ZSAH was significantly greater than that for the controlled soil.