Biosorption of Cd(II) Ions from Aqueous Solution Using Chitosan-iso-Vanillin as a Low-Cost Sorbent: Equilibrium, Kinetics, and Thermodynamic Studies

摘要

In the current study, the removal of Cd(II) ions from aqueous solution using chitosan-iso-vanillin biosorbent has been investigated. The impacts of pH, exposure time, adsorbent dosage and initial amount of studied ion on the removal process have been carried out using batch experiments. The quantity of residual ions has been estimated via atomic absorption spectrometry. The synthesized biosorbent is characterized using infrared spectroscopy, DTA, and SEM techniques. The maximum sorption of Cd(II) ions is achieved at pH 5. Langmuir isotherm works as the best explanation model for the experimental data with the highest adsorption capacity equal to 38.31 mg g(-1). Kinetic studies reveal that chemisorption is the rate-determining step, and the results point out fast rates of metal ion uptake with 77% highest percentage achieved after 60 min. Thermodynamics suggest spontaneous and endothermic process with raise in randomness at the solid/solution interface throughout the bio-adsorption of Cd(II) ions onto modified chitosan.