Abstract:

The adsorption behaviors of Ni(Ⅱ) ion on bamboo charcoal were investigated with various chemical methods in NaAc-HAc buffer system. The results showed: the sorption was controled by pH, average particle size, initial ion concentration, contact time and temperature and the statically saturated adsorption capacity of bamboo charcoal is 55.57 mg·g^-1 when the temperature was 298 K, pH was 3.0,C₀=0.113 mg·mL^-1, contact time was 24 h,particle size was 0.2-0.4 mm.Compared with pseudo-first-order kinetics, the adsorption of Ni(Ⅱ) ions fitted better with pseudo-second-order kinetics,and the equilibrium time was 100 min.The adsorption of Ni (Ⅱ) obeyed the Langmuir isotherm better than Freundlich isotherm. The adsorption capacity is greater, when the particle size of bamboo charcoal is smaller. The adsorption parameters of thermodynamic were ΔH=8.19 kJ·mol^-1, ΔS=78.12 J·mol^-1K^-1and ΔG_298K=-15.08 kJ·mol^-1. What’s more, the change of chemical functional groups was examined by IR spectrometry. This study demonstrated that bamboo charcoal could be used for the removal of Ni(Ⅱ) ions in water treatment.

Key words: bamboo charcoal, Ni(Ⅱ), adsorption, Langmuir isotherm, thermodynamics, kinetics, chemical functional groups