Effect of Thermal Regeneration on the Breakthrough Performance of Ceramsite Saturated with Methylene Blue

Abstract

The regeneration of a spent packing is crucial with respect to the development of circular economy and abstemious society. Thus, the effects of regeneration temperature, resistant time, heating rate, and regeneration cycle on the breakthrough performance of methylene blue (MB) dye-exhausted ceramsite in a two-stage fixed-bed column were studied in this work. Results illustrate that the ceramsite exhibited excellent potential regeneration properties under the following optimal regeneration conditions: treatment temperature was 600 ℃, resistant time was 15 min, heating rate was 20 ℃/min, regeneration cycle was over 9 cycles, and the breakthrough time, saturation time, regeneration efficiency (RE), and regeneration loss rate (RLR) were 540 min, 1020 min, 64.61%, and 17.73%, respectively. The RE declined by 35.14% in over 1 cycle, while the RLR increased by 3.15 times in over 9 cycles. Besides, Thomas model was suitable to describe the two-stage fixed-bed column adsorption and thermal regeneration process with R2=0.978. In conclusion, a thorough understanding of the regeneration behavior of the two-stage fixed-bed column packed with ceramsite provides reference to obtain an effective and feasible regeneration approach, and it is beneficial for further application in water treatment.