Catalyst-integrated adsorption for continuous purification of molasses toward efficient 5-hydroxymethylfurfural production

Abstract

This study presents an efficient continuous purification process for molasses, unlocking its potential as a sustainable feedstock for 5-hydroxymethylfurfural (5-HMF) production. The direct utilization of molasses has been limited by impurities that impair production efficiency. A novel purification strategy employing sequential adsorption with Amberlyst 21 (A21) and Amberlyst 15 (A15) achieves a remarkable 97 % impurity removal with minimal sugar loss (1.7 %), significantly outperforming traditional methods (2.8–16.4 % sugar loss). Optimal adsorption conditions were identified as 20 min at 30 °C for A21 and 5 min at 30 °C for A15. The purified molasses was subsequently used for continuous 5-HMF production. These adsorbents demonstrated dual functionality as catalysts, reducing the need for additional materials and enhancing the economic viability of the process. Under optimized conditions, including a molasses concentration of 30 g/L, a reaction time of 42 min, and an organic-to-aqueous volumetric ratio of 0.9:1, the 5-HMF yield of 18.6 % and selectivity of 53.8 % were achieved, comparable to those obtained using synthetic molasses. While these findings demonstrate significant progress, catalyst efficiency remains a critical bottleneck in further optimizing 5-HMF yields. Future research should focus on advancing catalyst performance to further enhance process efficiency.