Characterization of a low-cost Eucalyptus camaldulensis leaves based activated carbon for pharmaceutical residues removal from aqueous solutions

Due to their significant disposal problem during oil extraction and biofuel production, Eucalyptus camaldulensis leaves as an abundant forestry waste in the Mediterranean region, was investigated in this study as a precursor for the preparation of a low-cost adsorbents for the treatment of water laden with ascorbic acid (AA) as contaminant. A single step involving activation and carbonization in which the raw material was impregnated with chemical agent (KOH 20% and 40%) and then thermally decomposed at 600 degrees C to produce K-Eucal-20 and K-Eucal-40 adsorbents, respectively. Prior to adsorption tests, Fourier-transform infrared analysis, pH zpc determination, scanning electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller surface area, iodine number and methylene blue index were performed for structural and surface characterization. Important parameters affecting AA uptake including equilibrium time, adsorbent dose, solution pH and temperature were also evaluated. Adsorption isotherms were better described by the Langmuir model than those of Freundlich and Temkin. The maximum adsorption capacities achieved for AA were 190.80 and 305.78 mg/g, by K-Eucal-20 and K-Eucal-40, respectively. Kinetics was found to obey the pseudo-second-order model. Thermodynamic analysis confirms the spontaneity and endothermicity of AA adsorption process. This study shows that activated Eucalyptus camaldulensis leaves can be successfully used as an alternative to the commercially available adsorbents for the removal of such pollutant from liquid media.

Automated summary

In this study, Eucalyptus camaldulensis leaves were used as a precursor to prepare low-cost adsorbents for the treatment of water contaminated with ascorbic acid. The activated leaves proved to be effective in removing the pollutant from liquid media, making them a potential alternative to commercial adsorbents.