Chitosan-coated sour cherry kernel shell beads: an adsorbent for removal of Cr(VI) from acidic solutions

In this study, a composite biosorbent in the form of beads was produced from chitosan and the powder of sour cherry kernel shells. Characterization of chitosan-coated sour cherry kernel shell beads was done using elemental analysis, FT-IR spectroscopy, SEM, and EDX spectrum analysis. Adsorption capacity of chitosan-coated sour cherry kernel shell beads was tested in removal of Cr(VI) under different conditions, pH 2.0-7.0, adsorbent dosage 0.01-0. 20 g, initial Cr(VI) ion concentration 10-315 mg L-1, temperature 25-55 degrees C, and contact time 0-240 min, and compared to that of uncoated sour cherry kernel shell powder. Cr(VI) adsorption was highly dependent on the solution pH, and the maximum Cr(VI) adsorption was achieved at pH 2.03 at 25 degrees C in 45 min. The adsorption data was applied to Langmuir, Freundlich, Scatchard, and Dubinin-Radushkevich (D-R) adsorption isotherm models. According to the Langmuir isotherm model, the adsorption capacity of chitosan-coated sour cherry kernel shell beads was found higher than that of uncoated sour cherry kernel shell powder, 24.492 and 13.57 mg g(-1). The study demonstrated that chitosan-coated sour cherry kernel shell beads can be used for Cr(VI) removal from acidic aqueous solutions.