Sustainable Extraction and Valorization of Sunflower Stem Pith as an Absorbent Core for Hygiene Applications

This study aimed at the extraction of a natural biodegradable absorbent material from sunflower stem pith (SSP) as an eco-friendly option for hygiene products like baby diapers and sanitary pads. Researchers used sodium hypochlorite (NaOCl) treatment under mild conditions to effectively isolate the absorbent core. The process was optimized using response surface methodology (RSM) based on a central composite design (CCD), adjusting the solid-liquid ratio, extraction time, and temperature. The data proved that the best conditions, which were a 10 g/mL solid-liquid ratio, 15 minutes, and 95°C, led to an extraction efficiency of 68.85%. Statistical analysis (ANOVA) confirmed that the model was significant (p < 0.0001). FT-IR and TGA analysis showed that the extracted absorbent core had structural and thermal properties similar to commercially available products. The moisture retention tests revealed that NaOCl-treated samples absorbed more moisture due to optimal particle size and enhanced porosity. Water absorption and free swell tests further showed the superior absorbent performance of EAC. Overall, NaOCl treatment proved to be a viable, economical method for extracting high-yield absorbent core material from sunflower stem pith. KEYWORDS Absorption capacity, fibre morphology, hypochlorite treatment, medical textiles, process optimization, waste utilization