Citric acid - crosslinked cellulose derivatives superabsorbent hydrogels (SAH) as sustainable alternatives for personal hygiene applications

This study explores the development of citric acid (CA)-crosslinked superabsorbent hydrogels (SAHs) based on cellulose derivatives as sustainable alternatives to conventional petroleum-based superabsorbent polymers (SAPs) used in personal hygiene products. A biodegradable and biocompatible hydrogel formulation was synthesized using CA as a green crosslinking agent, with sodium carboxymethyl cellulose (Na-CMC) as the primary polymer and hydroxyethyl cellulose (HEC) as the secondary polymer, in varying ratios. The effects of polymer composition, swelling medium, pH, and water/saline solution absorption under load (AUL) were systematically evaluated by employing thermal analysis, rheology, water absorption capacity, swelling/deswelling kinetics, and soil biodegradation tests. Biocompatibility was also assessed via indirect contact cytotoxicity assays using mouse fibroblast cells. The optimized formulation, particularly the CMC—1.5 % CA hydrogel, exhibited high equilibrium water absorption (Q eq ) of 110 g/g in saline media at 38 °C, favorable swelling/deswelling behavior, rheological robustness, significant biodegradability (72 % within 7 weeks under composting conditions), and non-cytotoxicity (>80 % cell viability). These results highlight the potential of these hydrogels as biodegradable, biocompatible materials aligned with the Sustainable Development Goals (SDGs), especially for eco-friendly hygiene applications. • Citric acid–crosslinked cellulose hydrogels showed superior water absorption, exceeding commercial superabsorbents. • Hydrogels were up to 72 % biodegradable and non-cytotoxic, meeting key safety requirements. • Green-crosslinked cellulose hydrogels offer an eco-friendly alternative to synthetic absorbent materials. • The hydrogel process is simple, high-yield (>85 %), and scalable for industrial hygiene applications.