Adsorption property and mechanism of forest wastes based naturel adsorbent for removal of dye from aqueous media

Abstract

The present study aimed to determine the sorption behavior of crystal violet (CV) dye on forest wastes of Salix alba L. (white willow) (SA) and Salix babylonica L. (weeping willow) (SB). Forest waste adsorbents were investigated as a novel alternative natural adsorbent to removal of crystal violet (CV) in the polluted waters with the contact time (0-300 min), solution pH (2.8-9.1), initial dye concentration (25-150 mg/L), adsorbent dosage (1-15 g/L), and temperature (15-45 degrees C). The adsorbent materials were characterized by FTIR spectroscopy and isoelectric point (pHpzc) measurements. The isothermal adsorption property, the kinetic mechanisms, and thermodynamic adsorption characteristics of the adsorption of CV by adsorbents of SA and SB from forest wastes were investigated by the adsorption test. The equilibrium time of adsorption was found that 240 min for all adsorbents. The removal efficiency of SA and SB was 98.18% and 97.60%, at 5 g/L biosorbent dosages respectively. The second-order kinetic model was found to be best suited for all adsorbents (R-2 = 0.99). The adsorption isotherm data correspond well to the Langmuir equation and the adsorption capacity of SA and SB adsorbents was found to be 35.21 mg/g and 36.50 mg/g at 25 degrees C, respectively. The thermodynamic parameters suggest that, for both materials, the process was endothermic and spontaneous in the range of temperatures studied and the adsorbents utilized in this experiment can successfully remove CV dye from aqueous solution.