Carboxymethyl tamarind kernel gum-based superabsorbent hydrogel for release of copper micronutrient

Copper (Cu) is a vital micronutrient, and its deficiency can adversely affect plant growth and productivity. Thus, this study aims to design a hydrogel that can supply micronutrients in a sustained manner. The superabsorbent Pectin/poly(sodium methacrylate) (PSMA)/carboxymethyl tamarind kernel gum (CMTKG) hydrogel was synthesized, optimized and loaded with Cu micronutrient. The synthesized hydrogels were characterized using FTIR, SEM, and TGA techniques. The impact of distilled water, 0.9 % NaCl, pH 4, 7.4, 9, and 12 solutions on the swelling was studied. The hydrogel showed high swelling capacity (225.86 g/g in distilled water) and water holding capacity (57 %). The Cu release study demonstrated a sustained Cu release in soil, with 67.02 % released in 60 days, following the Korsmeyer-Peppas model and Fickian diffusion mechanism. The hydrogel demonstrated no toxic effect on soil microbes (Azotobacter). Additionally, the rheological studies revealed that the synthesized hydrogel possesses good elasticity. Additionally, the soil-burial degradability test revealed that hydrogel is 54 % degradable within 60 days, indicating potential for eco-friendly agricultural applications. The results demonstrate that the Cu-loaded Pectin/PSMA/CMTKG hydrogel has potential for sustained Cu release, promoting plant growth while minimizing environmental impact.