Adsorption of Chloramphenicol on Commercial and Modified Activated Carbons

Joanna Lach

doi:10.3390/w11061141

Abstract

The aim of the study was to evaluate the possibility of applying commercial activated carbons currently used in water treatment plants and modified carbon at 400 and 800 °C in the atmosphere of air, water vapour and carbon dioxide to remove chloramphenicol. Adsorption kinetics was examined for solutions with pH of 2–10. Adsorption kinetics were determined for the initial concentration of chloramphenicol of 161 mg/dm3 and the adsorption isotherm was determined for the concentrations of 161 to 1615 mg/dm3. Of the analysed activated carbons (F-300, F-100, WG-12, ROW 08 Supra and Picabiol), the highest adsorption capacity was obtained for the use of Picabiol (214 mg/g), characterized by the highest specific surface area and pore volume. The pH value of the solution has little effect on the adsorption of chloramphenicol (the highest adsorption was found for pH = 10, qm = 190 mg/g, whereas the lowest—for pH = 6, qm = 208 mg/g). Modification of activated carbon WG-12 at 800 °C caused an increase in adsorption capacity from 195 mg/g (unmodified carbon) to 343 mg/g. A high correlation coefficient was found between the capacity of activated carbons and the total volume of micropores and mesopores. Among the examined adsorption kinetics equations (pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion), the lowest values of the R2 correlation coefficient were obtained for the pseudo-first order equation. Other models with high correlation coefficient values described the adsorption kinetics. The adsorption results were modelled by means of the Freundlich, Langmuir, Temkin and Dubibin–Radushkevich adsorption isotherms. For all activated carbons and process conditions, the best match to the test results was obtained using the Langmuir model, whereas the lowest was found for the Dubibin–Radushkevich model.

Highlights

Antibiotics represent one of the groups of drugs whose discovery has revolutionized medicine.Since the invention of penicillin in 1928, many different natural and semi-synthetic antibiotics and chemotherapeutic agents have been developed
The kinetics of chloramphenicol adsorption from a 161 mg/L solution on all activated carbons used in the study (F-100, F-300, WG-12, ROW 08, Picabiol) were analysed
The shortest time of reaching adsorption equilibrium was obtained for activated carbon Picabiol (6 h), whereas the longest was for activated carbon F-300 (8 h)

Summary

Introduction

Antibiotics represent one of the groups of drugs whose discovery has revolutionized medicine. Since the invention of penicillin in 1928, many different natural and semi-synthetic antibiotics and chemotherapeutic agents (synthetic compounds not present in nature) have been developed. The fact that they are more and more widespread and frequently used (in human and animal medicine, and as animal growth promoters) has caused environmental pollution with these compounds. The sources of antibiotics and their pathways to the environment are diverse. In 2018, the use of antibiotics in the European Union (EU) to improve and accelerate the growth and development of farm animals was banned. The average human dose of antibiotic was 116.4 mg/kg, whereas for animals, this was 144.0 mg/kg [2,3]

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