Sustainable recovery of cellulose from lotus seedpods: Integrating process optimization and environmental-preliminary...

Cellulose is an abundant natural polymer; however, its extraction from agricultural residues remains limited in terms of environmental sustainability and economic efficiency. Therefore, for the first time, a combination of response surface methodology, life cycle assessment, and preliminary economic analysis was employed to optimize the extraction process of cellulose from lotus seedpods in an eco-friendly manner. Based on a functional unit of 1 g dried lotus seedpod, the predictive central composite design model demonstrated high accuracy and reliability, with the optimal extraction conditions of 4.30 % NaOH, 79.99 °C, 75.75  min, a raw material-to-solvent ratio of 1:10, and 0.2 % NaClO for bleaching, resulting in a cellulose extraction efficiency of 44.17 %, with corresponding environmental impacts of 2.40  kg CO₂ equivalent (climate change impact) and 0.82 × 10^-7 comparative toxic unit for humans (human toxicity impact). The extracted cellulose was also characterized using thermogravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and analysis of the lateral order index (A₁₄₂₂/A₈₉₆), total crystalline index (A₁₃₇₀/A₂₉₂₀), and hydrogen bond index (A₃₃₃₂/A₁₃₂₀), which demonstrated characteristics comparable to commercial cellulose. The life cycle assessment and preliminary economic analysis indicated that the optimal extraction process was significantly environmental-friendlier than the conventional method, with notable reductions in climate change potential, human toxicity, freshwater ecotoxicity, acidification, and water resource depletion, and improved cost-effectiveness (the extraction cost was reduced from 18.7 USD to 0.23 USD per functional unit). These findings highlight the potential for utilizing lotus seedpod-derived cellulose in biodegradable materials and environmentally sustainable industries.