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

(Beletech Alemu Reta, K. Murugesh Babu and Tamrat Tesfaye)

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Abstract

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

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References

Afridi, A.S., Chin, N.L., Ishak, N.A., Mohamad Yusof, N.N., Kadota, K., Manaf, Y.N. and Yusof, Y.A. (2021). Effect of sodium hypochlorite concentration during pre-treatment on isolation of nanocrystalline cellulose from Leucaena leucocephala (Lam.) mature pods. BioResources, 16(2), 3137–58. DOI: 10.15376/biores.16.2.3137-3158.
Ahmed, M.M., Nabi, M.H.B., Mia, M.S., Ahmad, I. and Zzaman, W. (2025). Valorization of plant-based agro-waste into sustainable food packaging materials: Current approaches and functional applications. Applied Food Research, 5(2), 101368. DOI: 10.1016/j.afres.2025.101368.
Arenas-Salazar, A.P., Schoor, M., Nieto-Ramírez, M.I., García-Trejo, J.F., Torres-Pacheco, I., Guevara-González, R.G., Acquirre-Becerra, H. and Feregrino-Pérez, A.A. (2025). Morphological and nutritional characterization of the native sunflower as a potential plant resource for the sierra gorda of querétaro. Resources, 14(8), 121. DOI: 10.3390/resources14080121.
Boateng, I.D. (2023). Application of graphical optimization, desirability, and multiple response functions in the extraction of food bioactive compounds. Food Engineering Reviews, 15(2), 309–28. DOI: 10.1007/s12393-023-09339-1.
Capizzi, M.T. and Ferguson, R. (2005). Loyalty trends for the twenty-first century. Journal of Consumer Marketing, 22(2), 72–80. DOI: 10.1108/07363760510589235.
Casquilho, M., Rodrigues, A. and Rosa, F. (2013). Superabsorbent polymer for water management in forestry. Agricultural Sciences, 4(5), 57–60. DOI: 10.4236/as.2013.45B011.
Costa, A.L.R., Gomes, A., Tibolla, H., Menegalli, F.C. and Cunha, R.L. (2018). Cellulose nanofibers from banana peels as a Pickering emulsifier: High energy emulsification processes. Carbohydrate Polymers, 194(15), 122–31. DOI: 10.1016/j.carbpol.2018.04.001.
Demirel, M. and Kayan, B. (2012). Application of response surface methodology and central composite design for the optimization of textile dye degradation by wet air oxidation. International Journal of Industrial Chemistry, 3(1), 1–10. DOI: 10.1186/2228 5547 3 24.
Dhiman, J., Anupam, K., Kumar, V. and Saruchi (2023). Bio-Based superabsorbent polymers: An overview. In: S. Pradhan and S. Mohanty (eds.) Bio-based Superabsorbents. Engineering Materials. Springer, Singapore. DOI: 10.1007/978-981-99-3094-4_1.
El Nemr, A. (2012). From natural to synthetic fibers. In: A. El Nemr (ed.) Textiles: Types, Uses and Production Methods. Nova Science Publishers. NY, USA.
Jain, H., Gupta, A., Kumar, R. and Mondal, D.P. (2019). Microstructure and compressive deformation behavior of SS foam made through evaporation of urea as space holder. Materials Chemistry and Physics, 223(1), 737–44. DOI: 10.1016/j.matchemphys.2018.11.040.
Jamshaid, H., Mishra, R.K., Raza, A., Hussain, U., Rahman, M.L., Nazari, S., Chandan, V., Muller, M. and Choteborsky, R. (2022). Natural cellulosic fiber reinforced concrete: Influence of fiber type and loading percentage on mechanical and water absorption performance. Materials, 15(3), 874. DOI: 10.3390/ma15030874.
Joo, J.H., Kim, S.H., Kim, J.H., Kang, H.J., Lee, J.H., Jeon, H.J. and Seo, M.K. (2025). Recent advances in activated carbon fibers for pollutant removal. Carbon Letters, 35(1), 21–44. DOI: 10.1007/s42823-024-00803-4.
Kamal, J. (2011). Quantification of alkaloids, phenols, and flavonoids in sunflower. African Journal of Biotechnology, 10(16), 49–3151. DOI: 10.5897/AJB09.1270.
Liu, J., Wang, X., Fan, Z., Liu, Z., Xu, P., Sawant, T.R., Huang, G., Deng, X., Guo, J., Wang, J. and Zhou, M. (2025). Valorization of agricultural residues: Challenges and opportunities in the production of bio-based materials - a route toward sustainable hygiene solutions. BioResources, 20(2), 4798–820. DOI: 10.15376/biores.20.2.Liu.
Mirzaie, A., Brandão, M. and Zarrabi, H. (2025). Toward eco-friendly menstrual products: A comparative life cycle assessment of sanitary pads made from bamboo pulp vs. a conventional one. Environmental Science and Pollution Research, 32(14), 9050–67. DOI: 10.1007/s11356-025-36269-8.
Muthu, S.S. and Li, Y. (2014). Assessment of Environmental Impact by Grocery Shopping Bags. An Eco-Functional Approach. Hong Kong: Springer.
Sareen, S. (2021). Sustainable menstrual alternatives: The journey so far. International Journal of Home Science, 7(3), 216–9. 
Sun, S., Mathias, J.D., Toussaint, E. and Grediac, M. (2013). Hygromechanical characterization of sunflower stems. Industrial Crops and Products, 46(n/a) 50–9. DOI: 10.1016/j.indcrop.2013.01.009.
Taj, S., Munawar, M.A. and Khan, S. (2007). Natural fiber-reinforced polymer composites. Pakistan Academy of Sciences, 44(2), 129–44. DOI: 10.1533/9781845695057.129.
Verma, S.K., Goswami, P., Verma, R.S., Padalia, R.C., Chauhan, A., Singh, V.R. and Darokar, M.P. (2016). Chemical composition and antimicrobial activity of bergamot-mint (Mentha citrata Ehrh.) essential oils isolated from the herbage and aqueous distillate using different methods. Industrial Crops and Products, 91(n/a),152–60. DOI: 10.1016/j.indcrop.2016.07.005.
Weise, U., Maloney, T. and Paulapuro, H. (1996). Quantification of water in different states of interaction with wood pulp fibres. Cellulose, 3(1), 189–202. DOI: 10.1007/BF02228801.
Wyman, C.E., Decker, S.R., Himmel, M.E., Brady, J.W., Skopec, C.E. and Viikari, L. (2005). Hydrolysis of cellulose and hemicellulose. Polysaccharides: Structural Diversity and Functional Versatility, 1(n/a), 1023–62.
Xu, M. (2016). Polysaccharides from Sunflower Stalk Pith: Chemical, Structural, and Partial Physicochemical Characterization. PhD Thesis, University of Guelph.
Xu, M., Qi, B., Yu, Q. and Li, Y. (2020). Polysaccharides from sunflower stalk pith: Chemical, structural and functional characterization. Food Hydrocolloids, 100(n/a), 105082. DOI: 10.1016/j.foodhyd.2019.04.053