Optimization of preparation conditions of modified activated carbon for alcoholic beverages and adsorption performance of furfural in Baijiu

In this study, the activated carbon with the worst adsorption effect among the 7 activated carbon was modified by phosphoric acid method, so as to improve its ability to remove furfural and reduce its adsorption of flavor components in Baijiu. With the comprehensive indexes of furfural removal rate and total ester retention rate in Baijiu as evaluation indexes, phosphoric acid content, impregnation ratio, activation temperature, time, carbonation temperature and time as influencing factors, the preparation conditions of modified activated carbon were optimized by single factor and orthogonal experiments. The structure of activated carbon before and after modification was characterized by BET specific surface area measurement method, scanning electron microscopy (SEM) and Fourier infrared spectroscopy (FTIR), and the adsorption properties of modified activated carbon for alcoholic beverages were analyzed. The results showed that the optimum preparation conditions were as follows: phosphoric acid content 35%, impregnation ratio 1∶7, activation temperature 200 ℃, time 2 h, carbonization temperature 300 ℃, and time 2.0 h. Under these optimal conditions, the furfural removal rate by modified activated carbon was increased from 13.18% to 39.28%, and the retention rate of total ester was increased from 87.09% to 97.96%. BET, SEM and FTIR results showed that the pore size (average pore size>2 nm) of activated carbon for alcoholic beverages was increased by phosphoric acid method. The adsorption performance tests results showed that the modified activated carbon could effectively improve the adsorption performance of activated carbon.