Adsorption characteristics of chloramphenicol onto powdered activated carbon and its desorption performance by ultrasound

ABSTRACT

In this work, the adsorption characteristics, including adsorption kinetic, isotherm and thermodynamics of chloramphenicol (CAP) onto powdered activated carbon (PAC), were carried out, and the feasibility of using ultrasound to regenerate saturated PAC in aqueous solution was evaluated. The adsorption results demonstrated that the adsorption mechanism was a complex process including surface adsorption, external liquid membrane diffusion and intraparticle diffusion as well, and the adsorption process was endothermic and non-spontaneous. The optimal conditions for PAC regeneration were as follows: acoustic density of 0.36 W/mL, saturated carbon dosage of 1.0 g/L and pH value of 10.36. The analysis of thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), Brunauer–Emmett–Teller (BET) surface area, pore size distribution and scanning electron microscopy (SEM) of PAC samples revealed that ultrasound mainly acted on surface functionalities, meso-pores and macro-pores of PAC through hydroxyl radical oxidization, high-pressure shock waves and high-speed microjets due to cavitation effect. This study highlighted that ultrasound could be efficiently desorbing CAP from saturated PAC. Practical applications of this method for PAC regeneration with complex natural matrices under environmentally realistic conditions were conducted and the adsorption capacity of the regenerated PAC decreased.

GRAPHICAL ABSTRACT

KEYWORDS:

• Chloramphenicol
• powdered activated carbon
• adsorption
• desorption
• ultrasound

Acknowledgements

We would like to give our sincere thanks to the peer-reviewers for their suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by National Natural Science Foundation of China: [Grant Number 51778012].