Effect of microwave heating on the regeneration of modified activated carbons saturated with phenol

Abstract

The purpose of this work was to investigate the effect of microwave irradiation on the regeneration of modified activated carbons (GAC/MW, GAC/Ni, and GAC/Cu). The untreated activated carbon (GAC pure) was used for blank experiment. Microwave heating was used for preparation and regeneration of the modified activated carbons. The effect of loading Ni2+ and Cu2+ ions on the activated carbon adsorption capacity was investigated. The results showed that the activated carbon loaded with Ni2+ has no significant effect on phenol adsorption, while the adsorption capacity of activated carbon loaded with Cu2+ significantly decreased. Microwave irradiation showed a positive effect on activated carbon adsorption capacity. Under optimal conditions, the results showed that there was no effect when changing temperature and pH. The effect of ions Ni2+ and Cu2+ loaded into activated carbon were also investigated. During the regeneration process, the activated carbon loaded with Ni2+ showed a strong microwave energy adsorption than the activated carbon loaded with Cu2+. The effect increasing Ni2+ quantity decreases the activated carbon regeneration efficiency. During the regeneration of activated carbons, the highest temperature was observed in the cases of GAC/Ni. During regeneration, the temperature increases when the quantity Ni2+ loaded increases. The regeneration efficiency of activated carbons reaches 98 % even after 10 times of regeneration cycles. After several regenerations, MW/GAC and GAC/Ni regeneration efficiency was high, while regeneration efficiency of GAC/Cu decreased considerably. GAC regeneration efficiency also decreased several cycles. During regeneration process, phenol was simply desorbed from activated carbons under microwave irradiation.