Study of the combination of sulfuric acid treatment and thermal regeneration of spent powdered activated carbons from decolourization process in glucosamine production

In this study, the combination of sulfuric acid treatment and thermal regeneration of spent powdered activated carbon (SPAC) saturated with color impurities and pigments was analyzed. The purposes of this work was to investigate effect of regeneration temperature on spent powdered activated carbons pretreated by H2SO4 solution (SPAC-H2SO4), and characterize porosity structure and property of regenerated samples by TG, BET, and FTIR methods in order to infer regeneration mechanism. The results showed that sintering rate of SPAC-H2SO4 was higher than that of SPAC at any temperature, indicating that H2SO4 pretreatment made SPAC more conducive to pyrolysis. Regeneration temperature had a noticeable effect on the regenerated yield. The optimal regeneration effect was obtained at 600 degrees C for SPAC-H2SO4. The iodine value, MB value, and S-BET of SPAC-H2SO4-600 were 1294.69 mg/g, 13.97 mL/0.1 g, and 1839.09 m(2)/g, respectively, which accounted for 99%, 93%, and 87% of fresh PAC, respectively. The adsorption rate of SPAC-H2SO4-600 and virgin PAC for methylene blue (MB) solution both followed well pseudo-second-order kinetics. These results indicated that combination of sulfuric acid treatment and thermal regeneration was a promising method for SPAC regeneration.