Ultrasonic And Microwave Regeneration Of Phenol-loaded Activated Carbons

Activated carbon is most economically attractive and feasible adsorbing material due to its easy operation and the development of various cheap adsorbents. When activated carbon reaches its saturation adsorption capacity, it is typically taken to a landfill where it can potentially pollute the surrounding leachate. However, the disposal of hazardous waste in landfills is becoming increasingly unacceptable because of the cost-prohibitive adsorbents and restrictive environmental regulations. Hence it is imperative to regenerate the spent activated carbon for economic, environmental and energy benefits.Therefore, the purpose of the current study was to examine the regeneration of phenol-loaded activated carbons via ultrasonic and microwave method. The effect of operating parameters such as the regeneration temperature, regeneration time and regeneration cycles would be studied systematically to identify the optimum conditions.In this study, the regeneration of spent activated carbon obtained from waste fiberboard(WFAC) under ultrasonic was investigated. And the optimal conditions of regeneration were:ultrasonic power 200 W, ultrasonic time 6 min and ultrasonic temperature 35℃ for 0.1g AC. Meanwhile, the optimal conditions of regeneration activated carbon obtained from arundo donax(ADAC) under ultrasonic were: ultrasonic power 180 W, ultrasonic time 9 min and ultrasonic temperature 38℃ for 0.1 g AC. When phenol solution was treated under the optimal conditions, two activated carbons (ACs) were different during six times of successive adsorption-regeneration cycles. The structural properties of original and regenerated ADAC and WFAC were characterized by N2 adsorption isotherms. After one adsorption-regeneration cycle, the BET surface area of the regenerated ADAC and WFAC were 1409m2/g and 1833 m2/g respectively, corresponding to the original ADAC is1688 m2/g and original WFAC is 1928 m2/g separately.The same study was performed for the microwave regeneration of AD AC and WFAC loaded with phenol. The regeneration of spent activated carbon (AC) under microwave irradiation was investigated.And the optimal conditions of regeneration were:microwave power 800 W, microwave irradiation time 7 min for 0.1 g AC. When phenol solution was treated under the optimal conditions, two activated carbons (ACs) were different during ten times of successive adsorption-regeneration cycles. The phenol adsorption for regenerated WFAC did not significantly reduced even after nine cycles of adsorption-regeneration. On the contrary, the regenerated ADAC adsorbing phenol began to decline obviously after the sixth cycle. The structural properties of original and regenerated ADAC and WFAC were characterized by the N2 adsorption isotherms. After one adsorption-regeneration cycle, the BET surface area of the regenerated ADAC and WFAC were 1954 m2/g and 1933 m2/g respectively, corresponding to the original ADAC is1988 m2/g and original WFAC is 1928 m2/g separately.