Study on Improving the Components Separation Efficiency of Eucalyptus by Alkali Pretreatment Coupled with Ternary DES System
In this study,a method for potassium hydroxide(KOH)pretreatment coupled with ternary deep eutectic solvent(DES)two-stage treat-ment was explored for component separation of eucalyptus.Initially,the KOH pretreatment conditions for separating hemicellulose from eucalyptus were optimized using methods of single-factor and Box-Behnken design.Subsequently,the microscopic morphology,specific surface area,and crystallinity of eucalyptus treated by KOH prepretreatment coupled with the ternary DES two-stage treatment were investigated.The results showed that the optimized KOH pretreatment conditions were determined as treatment temperature of 76℃,treatment time of 5 h,KOH mass fraction of 15%,at which the hemicellulose removal rate could reach(77.1±0.2)%.Following the KOH pretreatment coupled with ternary DES two-stage treatment(solid-liquid ratio of 1∶20(g∶mL),reaction time of 30 min,and reaction temperature of 90℃),the dense structure formed by cellu-lose,hemicellulose,and lignin in eucalyptus was disrupted,while the removal rates of hemicellulose and lignin reached 83.3%and 96.5%,re-spectively,while the retention rate of cellulose reached 91.0%.The specific surface area and relative crystallinity reached 0.901 5 m2/g and 89.7%,respectively,which significantly improved the contact surface area of subsequent solvents or biological enzymes.
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