Seul Lee  Jung-Jo Jung  Junseong Park

Vol. 31,  No. 4, pp. 285-293, Dec.  2025
10.7464/ksct.2025.31.4.285

Distillation Recycling N-methyl-2-pyrrolidon Response surface methodology

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This study aimed to design and optimize a vacuum distillation process for the efficient recovery of high-purity N-methyl-2-pyrrolidone (NMP) from waste mixtures generated during lithium-ion battery manufacturing. The process conditions were optimized using Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD), with temperature (X1), time (X2), and fill volume (X3) selected as independent variables, and NMP recovery rate as the response. Analysis of variance (ANOVA) confirmed that the developed model was statistically significant (p < 0.0001) with a high coefficient of determination (R2 = 0.9795). The 3D response surface and contour plots revealed that both temperature and distillation time were major factors influencing recovery efficiency. The optimal conditions were determined to be 83 oC, 30 min, and 21.5% fill volume, yielding a predicted recovery rate of 92.72%. Experimental validation under the same conditions showed an average recovery of 91.8%, within 5% error of the predicted value, verifying the model’s reliability. HPLC chromatograms confirmed that the recovered NMP exhibited equivalent purity to standard NMP. These results demonstrate that the optimized vacuum distillation process provides an energy-efficient and environmentally friendly approach for solvent recycling, contributing to resource circulation and sustainable secondary battery manufacturing.